travel around the sun planets

The solar system, explained

Our solar system is made up of the sun and all the amazing objects that travel around it.

The universe is filled with billions of star systems. Located inside galaxies, these cosmic arrangements are made up of at least one star and all the objects that travel around it, including planets, dwarf planets, moons, asteroids, comets, and meteoroids. The star system we’re most familiar with, of course, is our own.

Home sweet home

If you were to look at a giant picture of space, zoom in on the Milky Way galaxy , and then zoom in again on one of its outer spiral arms, you’d find the solar system. Astronomers believe it formed about 4.5 billion years ago, when a massive interstellar cloud of gas and dust collapsed on itself, giving rise to the star that anchors our solar system—that big ball of warmth known as the sun.

Along with the sun, our cosmic neighborhood includes the eight major planets. The closest to the sun is Mercury , followed by Venus , Earth, and Mars . These are known as terrestrial planets, because they’re solid and rocky. Beyond the orbit of Mars, you’ll find the main asteroid belt , a region of space rocks left over from the formation of the planets. Next come the much bigger gas giants Jupiter and Saturn , which is known for its large ring systems made of ice, rock, or both. Farther out are the ice giants Uranus and Neptune . Beyond that, a host of smaller icy worlds congregate in an enormous stretch of space called the Kuiper Belt. Perhaps the most famous resident there is Pluto . Once considered the ninth planet, Pluto is now officially classified as a dwarf planet , along with three other Kuiper Belt objects and Ceres in the asteroid belt.

Moons and other matter

More than 150 moons orbit worlds in our solar system. Known as natural satellites, they orbit planets, dwarf planets, asteroids, and other debris. Among the planets, moons are more common in the outer reaches of the solar system. Mercury and Venus are moon-free, Mars has two small moons, and Earth has just one. Meanwhile, Jupiter and Saturn have dozens, and Uranus and Neptune each have more than 10. Even though it’s relatively small, Pluto has five moons, one of which is so close to Pluto in size that some astronomers argue Pluto and this moon, Charon, are a binary system.

Too small to be called planets, asteroids are rocky chunks that also orbit our sun along with the space rocks known as meteoroids. Tens of thousands of asteroids are gathered in the belt that lies between the orbits of Mars and Jupiter. Comets, on the other hand, live inside the Kuiper Belt and even farther out in our solar system in a distant region called the Oort cloud .

Atmospheric conditions

The solar system is enveloped by a huge bubble called the heliosphere . Made of charged particles generated by the sun, the heliosphere shields planets and other objects from high-speed interstellar particles known as cosmic rays. Within the heliosphere, some of the planets are wrapped in their own bubbles—called magnetospheres —that protect them from the most harmful forms of solar radiation. Earth has a very strong magnetosphere, while Mars and Venus have none at all.

Most of the major planets also have atmospheres . Earth’s is composed mainly of nitrogen and oxygen—key for sustaining life. The atmospheres on terrestrial Venus and Mars are mostly carbon dioxide, while the thick atmospheres of Jupiter, Saturn, Uranus, and Neptune are made primarily of hydrogen and helium. Mercury doesn’t have an atmosphere at all. Instead scientists refer to its extremely thin covering of oxygen, hydrogen, sodium, helium, and potassium as an exosphere.

Moons can have atmospheres, too, but Saturn’s largest moon, Titan, is the only one known to have a thick atmosphere, which is made mostly of nitrogen.

Life beyond?

For centuries astronomers believed that Earth was the center of the universe, with the sun and all the other stars revolving around it. But in the 16th century, German mathematician and astronomer Nicolaus Copernicus upended that theory by providing strong evidence that Earth and the other planets travel around the sun.

Today, astronomers are studying other stars in our galaxy that host planets, including some star systems like our own that have multiple planetary companions. Based on the thousands of known worlds spotted so far, scientists estimate that billions of planetary systems must exist in the Milky Way galaxy alone.

So does Earth have a twin somewhere in the universe? With ever-advancing telescopes, robots, and other tools, astronomers of the future are sure to find out.

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Our Solar System

Released Tuesday, March 15, 2016
Visualizations by:

The 8 planets plus Pluto with planetary axis tilt

planets3x3_pluto_colorMercury_axis_tilt_1080p.mp4 (1920x1080) [9.2 MB]
planets3x3_pluto_colorMercury_axis_tilt_720p.mp4 (1280x720) [4.7 MB]
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planets3x3_pluto_colorMercury_axis_tilt_2160p.mp4 (3840x2160) [28.7 MB]
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Moons orbit planets. Right now, Jupiter has the most named moons—50. Mercury and Venus don't have any moons. Earth has one. It is the brightest object in our night sky. The Sun, of course, is the brightest object in our daytime sky. It lights up the moon, planets, comets, and asteroids.

The 8 planets plus Pluto

planets3x3_pluto_colorMercury_1080p.mp4 (1920x1080) [10.4 MB]
planets3x3_pluto_colorMercury_720p.mp4 (1280x720) [5.1 MB]
planets3x3_pluto_colorMercury_720p.webm (1280x720) [5.4 MB]
pluto_2304p.mp4 (4096x2304) [39.4 MB]
planets3x3_pluto_colorMercury_360p.mp4 (640x360) [1.4 MB]
3x3_pluto (4104x2304) [32.0 KB]
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The Sun plus the 8 planets with planetary axis tilt

planets3x3_sun_colorMercury_axis_tilt_1080p.mp4 (1920x1080) [12.4 MB]
planets3x3_sun_colorMercury_axis_tilt_720p.mp4 (1280x720) [5.9 MB]
planets3x3_sun_colorMercury_axis_tilt_720p.webm (1280x720) [5.1 MB]
sun_tilt_2304p.mp4 (4096x2304) [48.3 MB]
planets3x3_sun_colorMercury_axis_tilt_360p.mp4 (640x360) [1.5 MB]
3x3_sun_tilt (4104x2304) [32.0 KB]
planets3x3_sun_colorMercury_axis_tilt_1080p.00001_print.jpg (1024x576) [99.1 KB]

The Sun plus the 8 planets

planets3x3_sun_colorMercury_1080p.mp4 (1920x1080) [12.3 MB]
planets3x3_sun_colorMercury_720p.mp4 (1280x720) [5.8 MB]
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The 8 planets plus Pluto with planetary axis tilt, planet names only

planets3x3_pluto_colorMercury_axis_tilt_NAMEONLY_1080p.mp4 (1920x1080) [9.1 MB]
planets3x3_pluto_colorMercury_axis_tilt_NAMEONLY_720p.mp4 (1280x720) [4.7 MB]
planets3x3_pluto_colorMercury_axis_tilt_NAMEONLY_1080p.webm (1920x1080) [2.7 MB]
planets3x3_pluto_colorMercury_axis_tilt_NAMEONLY_2160p.mp4 (3840x2160) [28.6 MB]
planets3x3_pluto_colorMercury_axis_tilt_NAMEONLY_1080p.00001_print.jpg (1024x576) [67.9 KB]

The 8 planets plus Pluto with planetary axis tilt, no labels

planets3x3_pluto_colorMercury_axis_tilt_NOLABELS_1080p.mp4 (1920x1080) [9.1 MB]
planets3x3_pluto_colorMercury_axis_tilt_NOLABELS_720p.mp4 (1280x720) [4.7 MB]
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The 8 planets plus Pluto with planetary axis tilt for Jim Green Space Weather presentation, with artist's rendering of lightning storms on Jupiter and Saturn, and Pluto's moon Charon crossing

planets3x3jimgreenspaceweather2160p_1080p.mp4 (1920x1080) [9.4 MB]
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planets3x3jimgreenspaceweathernamesOnly1080p.mp4 (1920x1080) [9.4 MB]
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planets3x3jimgreenspaceweather2160p_2160p.mp4 (3840x2160) [27.4 MB]
planets3x3jimgreenspaceweathernamesOnly2160p.mp4 (3840x2160) [29.3 MB]
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The 8 planets plus Pluto with planetary axis tilt for Jim Green Space Weather presentation, with artist's rendering of lightning storms on Jupiter and Saturn, and Pluto's moon Charon crossing

For More Information

See the following sources:

Mercury - Enhanced Color Map
Earth - Blue Marble
Mars - Magellan/MDIM
Saturn - Voyager/Cassini-Huygen
Uranus - W.M. Keck Observatory
Neptune - Voyager
Pluto - New Horizons
Venus - Magellan
Planets & Moons
Hubble Space Telescope
Mars Reconnaissance Orbiter
New Horizons
Solar System

Please give credit for this item to: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington (Mercury), USGS Astrogeology Science Center (Venus, Mars), NASA's Goddard Space Flight Center/Space Telescope Science Institute (Jupiter), NASA/JPL/Space Science Institute (Saturn) and NASA's Goddard Space Flight Center (Earth, Jupiter, Uranus)

Amy Moran (Global Science and Technology, Inc.)

Release date

This page was originally published on Tuesday, March 15, 2016. This page was last updated on Tuesday, November 14, 2023 at 12:30 AM EST.

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3.2: The Laws of Planetary Motion

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Learning Objectives

By the end of this section, you will be able to:

Describe how Tycho Brahe and Johannes Kepler contributed to our understanding of how planets move around the Sun
Explain Kepler’s three laws of planetary motion

At about the time that Galileo was beginning his experiments with falling bodies, the efforts of two other scientists dramatically advanced our understanding of the motions of the planets. These two astronomers were the observer Tycho Brahe and the mathematician Johannes Kepler. Together, they placed the speculations of Copernicus on a sound mathematical basis and paved the way for the work of Isaac Newton in the next century.

Tycho Brahe’s Observatory

Three years after the publication of Copernicus’ De Revolutionibus , Tycho Brahe was born to a family of Danish nobility. He developed an early interest in astronomy and, as a young man, made significant astronomical observations. Among these was a careful study of what we now know was an exploding star that flared up to great brilliance in the night sky. His growing reputation gained him the patronage of the Danish King Frederick II, and at the age of 30, Brahe was able to establish a fine astronomical observatory on the North Sea island of Hven (Figure 3.2). Brahe was the last and greatest of the pre-telescopic observers in Europe.

Panel (a), at left, presents a highly stylized engraving of Tycho Brahe in his observatory at Hven. Panel (b), at right, shows a portrait of Johannes Kepler.

At Hven, Brahe made a continuous record of the positions of the Sun, Moon, and planets for almost 20 years. His extensive and precise observations enabled him to note that the positions of the planets varied from those given in published tables, which were based on the work of Ptolemy. These data were extremely valuable, but Brahe didn’t have the ability to analyze them and develop a better model than what Ptolemy had published. He was further inhibited because he was an extravagant and cantankerous fellow, and he accumulated enemies among government officials. When his patron, Frederick II, died in 1597, Brahe lost his political base and decided to leave Denmark. He took up residence in Prague, where he became court astronomer to Emperor Rudolf of Bohemia. There, in the year before his death, Brahe found a most able young mathematician, Johannes Kepler, to assist him in analyzing his extensive planetary data.

Johannes Kepler

Johannes Kepler was born into a poor family in the German province of Württemberg and lived much of his life amid the turmoil of the Thirty Years’ War (see Figure 3.2). He attended university at Tubingen and studied for a theological career. There, he learned the principles of the Copernican system and became converted to the heliocentric hypothesis. Eventually, Kepler went to Prague to serve as an assistant to Brahe, who set him to work trying to find a satisfactory theory of planetary motion—one that was compatible with the long series of observations made at Hven. Brahe was reluctant to provide Kepler with much material at any one time for fear that Kepler would discover the secrets of the universal motion by himself, thereby robbing Brahe of some of the glory. Only after Brahe’s death in 1601 did Kepler get full possession of the priceless records. Their study occupied most of Kepler’s time for more than 20 years.

Through his analysis of the motions of the planets, Kepler developed a series of principles, now known as Kepler’s three laws, which described the behavior of planets based on their paths through space. The first two laws of planetary motion were published in 1609 in The New Astronomy . Their discovery was a profound step in the development of modern science.

The First Two Laws of Planetary Motion

The path of an object through space is called its orbit . Kepler initially assumed that the orbits of planets were circles, but doing so did not allow him to find orbits that were consistent with Brahe’s observations. Working with the data for Mars, he eventually discovered that the orbit of that planet had the shape of a somewhat flattened circle, or ellipse . Next to the circle, the ellipse is the simplest kind of closed curve, belonging to a family of curves known as conic sections (Figure 3.3).

This figure illustrates the conic sections. A cone is drawn with the circular base at bottom and the apex at top. From top to bottom: a “Circle” (drawn in orange) is formed when the intersecting plane is parallel to, but does not touch, the base. An “Ellipse” (drawn in red) is formed when the intersecting plane is at an angle to, but does not touch, the base. A “Parabola” (drawn in aqua) is formed when the intersecting plane is at an angle with and also touches the base. A “Hyperbola” (drawn in blue) is formed when the intersecting plane is nearly perpendicular to and also touches the base.

You might recall from math classes that in a circle, the center is a special point. The distance from the center to anywhere on the circle is exactly the same. In an ellipse, the sum of the distance from two special points inside the ellipse to any point on the ellipse is always the same. These two points inside the ellipse are called its foci (singular: focus ), a word invented for this purpose by Kepler.

This property suggests a simple way to draw an ellipse (Figure 3.4). We wrap the ends of a loop of string around two tacks pushed through a sheet of paper into a drawing board, so that the string is slack. If we push a pencil against the string, making the string taut, and then slide the pencil against the string all around the tacks, the curve that results is an ellipse. At any point where the pencil may be, the sum of the distances from the pencil to the two tacks is a constant length—the length of the string. The tacks are at the two foci of the ellipse.

The widest diameter of the ellipse is called its major axis . Half this distance—that is, the distance from the center of the ellipse to one end—is the semimajor axis , which is usually used to specify the size of the ellipse. For example, the semimajor axis of the orbit of Mars, which is also the planet’s average distance from the Sun, is 228 million kilometers.

Drawing an Ellipse. Panel (a), at left, illustrates how to draw an ellipse. The center of the ellipse is marked with a red dot, and the two thumbtacks in grey. A hand holds a pencil and traces out the ellipse using the string attached to the thumbtacks. Panel (b), at right, shows the both semimajor axes of the ellipse: the distances from the center to the edges farthest from the center.

The shape (roundness) of an ellipse depends on how close together the two foci are, compared with the major axis. The ratio of the distance between the foci to the length of the major axis is called the eccentricity of the ellipse.

If the foci (or tacks) are moved to the same location, then the distance between the foci would be zero. This means that the eccentricity is zero and the ellipse is just a circle; thus, a circle can be called an ellipse of zero eccentricity. In a circle, the semimajor axis would be the radius.

Next, we can make ellipses of various elongations (or extended lengths) by varying the spacing of the tacks (as long as they are not farther apart than the length of the string). The greater the eccentricity, the more elongated is the ellipse, up to a maximum eccentricity of 1.0 1.0 , when the ellipse becomes “flat,” the other extreme from a circle.

The size and shape of an ellipse are completely specified by its semimajor axis and its eccentricity. Using Brahe’s data, Kepler found that Mars has an elliptical orbit, with the Sun at one focus (the other focus is empty). The eccentricity of the orbit of Mars is only about 0.1 0.1 ; its orbit, drawn to scale, would be practically indistinguishable from a circle, but the difference turned out to be critical for understanding planetary motions.

Kepler generalized this result in his first law and said that the orbits of all the planets are ellipses . Here was a decisive moment in the history of human thought: it was not necessary to have only circles in order to have an acceptable cosmos. The universe could be a bit more complex than the Greek philosophers had wanted it to be.

Kepler’s second law deals with the speed with which each planet moves along its ellipse, also known as its orbital speed . Working with Brahe’s observations of Mars, Kepler discovered that the planet speeds up as it comes closer to the Sun and slows down as it pulls away from the Sun. He expressed the precise form of this relationship by imagining that the Sun and Mars are connected by a straight, elastic line. When Mars is closer to the Sun (positions 1 and 2 in Figure 3.5), the elastic line is not stretched as much, and the planet moves rapidly. Farther from the Sun, as in positions 3 and 4, the line is stretched a lot, and the planet does not move so fast. As Mars travels in its elliptical orbit around the Sun, the elastic line sweeps out areas of the ellipse as it moves (the colored regions in our figure). Kepler found that in equal intervals of time (t), the areas swept out in space by this imaginary line are always equal; that is, the area of the region B from 1 to 2 is the same as that of region A from 3 to 4.

If a planet moves in a circular orbit, the elastic line is always stretched the same amount and the planet moves at a constant speed around its orbit. But, as Kepler discovered, in most orbits that speed of a planet orbiting its star (or moon orbiting its planet) tends to vary because the orbit is elliptical.

Kepler’s Second Law. In this figure, the Sun is drawn at the right had focus of the elliptical orbit drawn in blue, with an arrow pointing to the right indicating counterclockwise motion. On the right an area “A”, drawn as a fat yellow wedge with the apex at the center of the Sun, is swept out from t=1 to 2. On the left an area “A”, drawn as a long, narrow yellow wedge with the apex at the center of the Sun, is swept out from t=3 to 4. Both wedges have the same area.

Link to Learning

The Kepler's Second Law demonstrator from CCNY's ScienceSims project shows how an orbiting planet sweeps out the same area in the same time.

Kepler’s Third Law

Kepler’s first two laws of planetary motion describe the shape of a planet’s orbit and allow us to calculate the speed of its motion at any point in the orbit. Kepler was pleased to have discovered such fundamental rules, but they did not satisfy his quest to fully understand planetary motions. He wanted to know why the orbits of the planets were spaced as they are and to find a mathematical pattern in their movements—a “harmony of the spheres” as he called it. For many years he worked to discover mathematical relationships governing planetary spacing and the time each planet took to go around the Sun.

In 1619, Kepler discovered a basic relationship to relate the planets’ orbits to their relative distances from the Sun. We define a planet’s orbital period , ( P ), as the time it takes a planet to travel once around the Sun. Also, recall that a planet’s semimajor axis, a, is equal to its average distance from the Sun. The relationship, now known as Kepler’s third law , says that a planet’s orbital period squared is proportional to the semimajor axis of its orbit cubed, or

P 2 ∝ a 3 P 2 ∝ a 3

When P (the orbital period) is measured in years, and a is expressed in a quantity known as an astronomical unit (AU) , the two sides of the formula are not only proportional but equal. One AU is the average distance between Earth and the Sun and is approximately equal to 1.5 × 10 8 1.5 × 10 8 kilometers. In these units,

P 2 = a 3 P 2 = a 3

Kepler’s third law applies to all objects orbiting the Sun, including Earth, and provides a means for calculating their relative distances from the Sun from the time they take to orbit. Let’s look at a specific example to illustrate how useful Kepler’s third law is.

For instance, suppose you time how long Mars takes to go around the Sun (in Earth years). Kepler’s third law can then be used to calculate Mars’ average distance from the Sun. Mars’ orbital period (1.88 Earth years) squared, or P 2 P 2 , is 1.88 2 = 3.53 1.88 2 = 3.53 , and according to the equation for Kepler’s third law, this equals the cube of its semimajor axis, or a 3 a 3 . So what number must be cubed to give 3.53? The answer is 1.52 1.52 ( since 1.52 × 1.52 × 1.52 = 3.53 ) ( since 1.52 × 1.52 × 1.52 = 3.53 ) . Thus, Mars’ semimajor axis in astronomical units must be 1.52 AU. In other words, to go around the Sun in a little less than two years, Mars must be about 50% (half again) as far from the Sun as Earth is.

Example 3.1: Calculating Periods

Imagine an object is traveling around the Sun. What would be the orbital period of the object if its orbit has a semimajor axis of 50 AU?

From Kepler’s third law, we know that (when we use units of years and AU)

If the object’s orbit has a semimajor axis of 50 AU ( a = 50), we can cube 50 and then take the square root of the result to get P:

P = a 3 P = 50 × 50 × 50 = 125,000 = 353.6 years P = a 3 P = 50 × 50 × 50 = 125,000 = 353.6 years

Therefore, the orbital period of the object is about 350 years. This would place our hypothetical object beyond the orbit of Pluto.

Exercise \(\PageIndex{1}\)

What would be the orbital period of an asteroid (a rocky chunk between Mars and Jupiter) with a semimajor axis of 3 AU?

P = 3 × 3 × 3 = 27 = 5.2 years P = 3 × 3 × 3 = 27 = 5.2 years

Kepler’s three laws of planetary motion can be summarized as follows:

Kepler’s first law : Each planet moves around the Sun in an orbit that is an ellipse, with the Sun at one focus of the ellipse.
Kepler’s second law : The straight line joining a planet and the Sun sweeps out equal areas in space in equal intervals of time.
Kepler’s third law : The square of a planet’s orbital period is directly proportional to the cube of the semimajor axis of its orbit.

Kepler’s three laws provide a precise geometric description of planetary motion within the framework of the Copernican system. With these tools, it was possible to calculate planetary positions with greatly improved precision. Still, Kepler’s laws are purely descriptive: they do not help us understand what forces of nature constrain the planets to follow this particular set of rules. That step was left to Isaac Newton.

Example 3.2: Applying Kepler’s Third Law

Using the orbital periods and semimajor axes for Venus and Earth that are provided here, calculate p 2 p 2 and a 3 a 3 , and verify that they obey Kepler’s third law . Venus’ orbital period is 0.62 year, and its semimajor axis is 0.72 AU. Earth’s orbital period is 1.00 year, and its semimajor axis is 1.00 AU.

We can use the equation for Kepler’s third law, P 2 ∝ a 3 . For Venus, P 2 = 0.62 × 0.62 = 0.38 P 2 = 0.62 × 0.62 = 0.38 and a 3 = 0.72 × 0.72 × 0.72 = .037 a 3 = 0.72 × 0.72 × 0.72 = .037 (rounding numbers sometimes causes minor discrepancies like this). The square of the orbital period (0.38) approximates the cube of the semimajor axis (0.37). Therefore, Venus obeys Kepler’s third law. For Earth, P 2 = 1.00 × 1.00 = 1.00 P 2 = 1.00 × 1.00 = 1.00 and a 3 = 1.00 × 1.00 × 1.00 = 1.00 a 3 = 1.00 × 1.00 × 1.00 = 1.00 . The square of the orbital period (1.00) approximates (in this case, equals) the cube of the semimajor axis (1.00). Therefore, Earth obeys Kepler’s third law.

Using the orbital periods and semimajor axes for Saturn and Jupiter that are provided here, calculate P 2 and a 3 , and verify that they obey Kepler’s third law. Saturn’s orbital period is 29.46 years, and its semimajor axis is 9.54 AU. Jupiter’s orbital period is 11.86 years, and its semimajor axis is 5.20 AU.

For Saturn, P 2 = 29.46 × 29.46 = 867.9 P 2 = 29.46 × 29.46 = 867.9 and a 3 = 9.54 × 9.54 × 9.54 = 868.3 a 3 = 9.54 × 9.54 × 9.54 = 868.3 . The square of the orbital period (867.9) approximates the cube of the semimajor axis (868.3). Therefore, Saturn obeys Kepler’s third law.

In honor of the scientist who first devised the laws that govern the motions of planets, the team that built the first spacecraft to search for planets orbiting other stars decided to name the probe “Kepler.” Visit NASA's Kepler website to learn more about Johannes Kepler’s life and his laws of planetary motion. NASA’s Kepler website and follow the links that interest you.

Biology, Earth Science, Astronomy, Physics

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The sun is an ordinary star , one of about 100 billion in our galaxy , the Milky Way. The sun has extremely important influences on our planet: It drives weather, ocean currents, seasons, and climate , and makes plant life possible through photosynthesis . Without the sun’s heat and light, life on Earth would not exist. About 4.5 billion years ago, the sun began to take shape from a molecular cloud that was mainly composed of hydrogen and helium. A nearby supernova emitted a shockwave, which came in contact with the molecular cloud and energized it. The molecular cloud began to compress , and some regions of gas collapsed under their own gravitational pull . As one of these regions collapsed, it also began to rotate and heat up from increasing pressure. Much of the hydrogen and helium remained in the center of this hot, rotating mass. Eventually, the gases heated up enough to begin nuclear fusion , and became the sun in our solar system . Other parts of the molecular cloud cooled into a disc around the brand-new sun and became planets, asteroids, comets, and other bodies in our solar system. The sun is about 150 million kilometers (93 million miles) from Earth. This distance, called an astronomical unit (AU), is a standard measure of distance for astronomers and astrophysicists. An AU can be measured at light speed, or the time it takes for a photon of light to travel from the sun to Earth. It takes light about eight minutes and 19 seconds to reach Earth from the sun. The radius of the sun, or the distance from the very center to the outer limits, is about 700,000 kilometers (432,000 miles). That distance is about 109 times the size of Earth’s radius. The sun not only has a much larger radius than Earth—it is also much more massive. The sun’s mass is more than 333,000 times that of Earth, and contains about 99.8 percent of all of the mass in the entire solar system! Composition The sun is made up of a blazing combination of gases. These gases are actually in the form of plasma . Plasma is a state of matter similar to gas, but with most of the particles ionized . This means the particles have an increased or reduced number of electrons. About three quarters of the sun is hydrogen, which is constantly fusing together and creating helium by a process called nuclear fusion. Helium makes up almost the entire remaining quarter. A very small percentage (1.69 percent) of the sun’s mass is made up of other gases and metals: iron, nickel, oxygen, silicon, sulfur, magnesium, carbon, neon, calcium, and chromium This 1.69 percent may seem insignificant, but its mass is still 5,628 times the mass of Earth. The sun is not a solid mass. It does not have the easily identifiable boundaries of rocky planets like Earth. Instead, the sun is composed of layers made up almost entirely of hydrogen and helium. These gases carry out different functions in each layer, and the sun’s layers are measured by their percentage of the sun’s total radius. The sun is permeated and somewhat controlled by a magnetic field . The magnetic field is defined by a combination of three complex mechanisms: a circular electric current that runs through the sun, layers of the sun that rotate at different speeds, and the sun’s ability to conduct electricity . Near the sun’s equator , magnetic field lines make small loops near the surface. Magnetic field lines that flow through the poles extend much farther, thousands of kilometers, before returning to the opposite pole. The sun rotates around its own axis, just like Earth. The sun rotates counterclockwise, and takes between 25 and 35 days to complete a single rotation. The sun orbits clockwise around the center of the Milky Way. Its orbit is between 24,000 and 26,000 light-years away from the galactic center. The sun takes about 225 million to 250 million years to orbit one time around the galactic center. Electromagnetic Radiation The sun’s energy travels to Earth at the speed of light in the form of electromagnetic radiation (EMR). The electromagnetic spectrum exists as waves of different frequencies and wavelengths . The frequency of a wave represents how many times the wave repeats itself in a certain unit of time. Waves with very short wavelengths repeat themselves several times in a given unit of time, so they are high-frequency. In contrast, low-frequency waves have much longer wavelengths. The vast majority of electromagnetic waves that come from the sun are invisible to us. The most high-frequency waves emitted by the sun are gamma rays, x-rays, and ultraviolet radiation (UV rays). The most harmful UV rays are almost completely absorbed by Earth’s atmosphere. Less potent UV rays travel through the atmosphere, and can cause sunburn. The sun also emits infrared radiation —whose waves are a much lower-frequency. Most heat from the sun arrives as infrared energy. Sandwiched between infrared and UV is the visible spectrum, which contains all the colors we, as humans, can see. The color red has the longest wavelengths (closest to infrared), and violet (closest to UV) the shortest. The sun itself is white, which means it contains all the colors in the visible spectrum. The sun appears orangish-yellow because the blue light it emits has a shorter wavelength, and is scattered in the atmosphere—the same process that makes the sky appear blue. Astronomers, however, call the sun a “yellow dwarf” star because its colors fall within the yellow-green section of the electromagnetic spectrum. Evolution of the Sun The sun, although it has sustained all life on our planet, will not shine forever. The sun has already existed for about 4.5 billion years. The process of nuclear fusion, which creates the heat and light that make life on our planet possible, is also the process that slowly changes the sun’s composition. Through nuclear fusion, the sun is constantly using up the hydrogen in its core : Every second, the sun fuses around 620 million metric tons of hydrogen into helium. At this stage in the sun’s life, its core is about 74 percent hydrogen. Over the next five billion years, the sun will burn through most of its hydrogen, and helium will become its major source of fuel. Over those five billion years, the sun will go from “yellow dwarf” to “ red giant .” When almost all of the hydrogen in the sun’s core has been consumed, the core will contract and heat up, increasing the amount of nuclear fusion that takes place. The outer layers of the sun will expand from this extra energy. The sun will expand to about 200 times its current radius, swallowing Mercury and Venus. Astrophysicists debate whether Earth’s orbit would expand beyond the sun’s reach, or if our planet would be engulfed by the sun as well. As the sun expands, it will spread its energy over a larger surface area, which has an overall cooling effect on the star. This cooling will shift the sun’s visible light to a reddish color—a red giant. Eventually, the sun’s core reaches a temperature of about 100 million on the Kelvin scale (almost 100 million degrees Celsius or 180 million degrees Farenheit), the common scientific scale for measuring temperature. When it reaches this temperature, helium will begin fusing to create carbon, a much heavier element. This will cause intense solar wind and other solar activity, which will eventually throw off the entire outer layers of the sun. The red giant phase will be over. Only the sun’s carbon core will be left, and as a “ white dwarf ,” it will not create or emit energy. Sun’s Structure The sun is made up of six layers: core, radiative zone , convective zone, photosphere , chromosphere , and corona . Core The sun’s core , more than a thousand times the size of Earth and more than 10 times denser than lead, is a huge furnace. Temperatures in the core exceed 15.7 million kelvin (also 15.7 million degrees Celsius, or 28 million degrees Fahrenheit). The core extends to about 25 percent of the sun’s radius. The core is the only place where nuclear fusion reactions can happen. The sun’s other layers are heated from the nuclear energy created there. Protons of hydrogen atoms violently collide and fuse, or join together, to create a helium atom. This process, known as a PP (proton-proton) chain reaction, emits an enormous amount of energy. The energy released during one second of solar fusion is far greater than that released in the explosion of hundreds of thousands of hydrogen bombs. During nuclear fusion in the core, two types of energy are released: photons and neutrinos . These particles carry and emit the light, heat, and energy of the sun. Photons are the smallest particle of light and other forms of electromagnetic radiation. Neutrinos are more difficult to detect, and only account for about two percent of the sun’s total energy. The sun emits both photons and neutrinos in all directions, all the time. Radiative Zone The radiative zone of the sun starts at about 25 percent of the radius, and extends to about 70 percent of the radius. In this broad zone, heat from the core cools dramatically, from between seven million K (12 million°F or 7 million°C) to two million K (2 million°C or 4 million°F). In the radiative zone, energy is transferred by a process called thermal radiation. During this process, photons that were released in the core travel a short distance, are absorbed by a nearby ion, released by that ion, and absorbed again by another. One photon can continue this process for almost 200,000 years! Transition Zone : Tachocline Between the radiative zone and the next layer, the convective zone, there is a transition zone called the tachocline. This region is created as a result of the sun’s differential rotation . Differential rotation happens when different parts of an object rotate at different velocities. The sun is made up of gases undergoing different processes at different layers and different latitudes. The sun’s equator rotates much faster than its poles, for instance. The rotation rate of the sun changes rapidly in the tachocline. Convective Zone At around 70 percent of the sun’s radius, the convective zone begins. In this zone, the sun’s temperature is not hot enough to transfer energy by thermal radiation. Instead, it transfers heat by thermal convection through thermal columns. Similar to water boiling in a pot, or hot wax in a lava lamp, gases deep in the sun’s convective zone are heated and “boil” outward, away from the sun’s core, through thermal columns. When the gases reach the outer limits of the convective zone, they cool down, and plunge back to the base of the convective zone, to be heated again. Photosphere The photosphere is the bright yellow, visible "surface" of the sun. The photosphere is about 400 kilometers (250 miles) thick, and temperatures there reach about 6,000K (5,700°C, 10,300°F). The thermal columns of the convection zone are visible in the photosphere, bubbling like boiling oatmeal. Through powerful telescopes, the tops of the columns appear as granules crowded across the sun. Each granule has a bright center, which is the hot gas rising through a thermal column. The granules’ dark edges are the cool gas descending back down the column to the bottom of the convective zone. Although the tops of the thermal columns look like small granules, they are usually more than 1,000 kilometers (621 miles) across. Most thermal columns exist for about eight to 20 minutes before they dissolve and form new columns. There are also “supergranules” that can be up to 30,000 kilometers (18,641 miles) across, and last for up to 24 hours. Sunspots , solar flares , and solar prominences take form in the photosphere, although they are the result of processes and disruptions in other layers of the sun. Photosphere: Sunspots A sunspot is just what it sounds like—a dark spot on the sun. A sunspot forms when intense magnetic activity in the convective zone ruptures a thermal column. At the top of the ruptured column (visible in the photosphere), temperature is temporarily decreased because hot gases are not reaching it. Photosphere: Solar Flares The process of creating sunspots opens a connection between the corona (the very outer layer of the sun) and the sun’s interior. Solar matter surges out of this opening in formations called solar flares. These explosions are massive: In the period of a few minutes, solar flares release the equivalent of about 160 billion megatons of TNT, or about a sixth of the total energy the sun releases in one second. Clouds of ions, atoms, and electrons erupt from solar flares, and reach Earth in about two days. Solar flares and solar prominences contribute to space weather , which can cause disturbances to Earth’s atmosphere and magnetic field, as well as disrupt satellite and telecommunications systems. Photosphere: Coronal Mass Ejections Coronal mass ejections (CMEs) are another type of solar activity caused by the constant movement and disturbances within the sun’s magnetic field. CMEs typically form near the active regions of sunspots, the correlation between the two has not been proven. The cause of CMEs is still being studied, and it is hypothesized that disruptions in either the photosphere or corona lead to these violent solar explosions. Photosphere: Solar Prominence Solar prominences are bright loops of solar matter. They can burst far into the coronal layer of the sun, expanding hundreds of kilometers per second. These curved and twisted features can reach hundreds of thousands of kilometers in height and width, and last anywhere from a few days to a few months. Solar prominences are cooler than the corona, and they appear as darker strands against the sun. For this reason, they are also known as filaments. Photosphere: Solar Cycle The sun does not constantly emit sunspots and solar ejecta; it goes through a cycle of about 11 years. During this solar cycle, the frequency of solar flares changes. During solar maximums, there can be several flares per day. During solar minimums, there may be fewer than one a week. The solar cycle is defined by the sun’s magnetic fields, which loop around the sun and connect at the two poles. Every 11 years, the magnetic fields reverse, causing a disruption that leads to solar activity and sunspots. The solar cycle can have effects on Earth’s climate. For example, the sun’s ultraviolet light splits oxygen in the stratosphere and strengthens Earth’s protective ozone layer . During the solar minimum, there are low amounts of UV rays, which means that Earth’s ozone layer is temporarily thinned. This allows more UV rays to enter and heat Earth’s atmosphere. Solar Atmosphere The solar atmosphere is the hottest region of the sun. It is made up of the chromosphere, the corona, and a transition zone called the solar transition region that connects the two. The solar atmosphere is obscured by the bright light emitted by the photosphere, and it can rarely be seen without special instruments. Only during solar eclipses , when the moon moves between Earth and the sun and hides the photosphere, can these layers be seen with the unaided eye. Chromosphere The pinkish-red chromosphere is about 2,000 kilometers (1,250 miles) thick and riddled with jets of hot gas. At the bottom of the chromosphere, where it meets the photosphere, the sun is at its coolest, at about 4,400K (4,100°C, 7,500°F). This low temperature gives the chromosphere its pink color. The temperature in the chromosphere increases with altitude, and reaches 25,000K (25,000°C, 45,000°F) at the outer edge of the region. The chromosphere gives off jets of burning gases called spicules , similar to solar flares. These fiery wisps of gas reach out from the chromosphere like long, flaming fingers; they are usually about 500 kilometers (310 miles) in diameter. Spicules only last for about 15 minutes, but can reach thousands of kilometers in height before collapsing and dissolving. Solar Transition Region The solar transition region (STR) separates the chromosphere from the corona. Below the STR, the layers of the sun are controlled and stay separate because of gravity, gas pressure, and the different processes of exchanging energy. Above the STR, the motion and shape of the layers are much more dynamic. They are dominated by magnetic forces. These magnetic forces can put into action solar events such as coronal loops and the solar wind. The state of helium in these two regions has differences as well. Below the STR, helium is partially ionized. This means it has lost an electron, but still has one left. Around the STR, helium absorbs a bit more heat and loses its last electron. Its temperature soars to almost one million K (one million°C, 1.8 million°F). Corona The corona is the wispy outermost layer of the solar atmosphere, and can extend millions of kilometers into space. Gases in the corona burn at about one million K (one million°C, 1.8 million°F), and move about 145 kilometers (90 miles) per second. Some of the particles reach an escape velocity of 400 kilometers per second (249 miles per second). They escape the sun’s gravitational pull and become the solar wind. The solar wind blasts from the sun to the edge of the solar system. Other particles form coronal loops. Coronal loops are bursts of particles that curve back around to a nearby sunspot. Near the sun’s poles are coronal holes. These areas are colder and darker than other regions of the sun, and allow some of the fastest-moving parts of the solar wind to pass through. Solar Wind The solar wind is a stream of extremely hot, charged particles that are thrown out from the upper atmosphere of the sun. This means that every 150 million years, the sun loses a mass equal to that of Earth. However, even at this rate of loss, the sun has only lost about 0.01 percent of its total mass from solar wind. The solar wind blows in all directions. It continues moving at that speed for about 10 billion kilometers (six billion miles). Some of the particles in the solar wind slip through Earth’s magnetic field and into its upper atmosphere near the poles. As they collide with our planet's atmosphere, these charged particles set the atmosphere aglow with color, creating auroras , colorful light displays known as the Northern and Southern Lights. Solar winds can also cause solar storms . These storms can interfere with satellites and knock out power grids on Earth. The solar wind fills the heliosphere, the massive bubble of charged particles that encompasses the solar system. The solar wind eventually slows down near the border of the heliosphere, at a theoretical boundary called the heliopause . This boundary separates the matter and energy of our solar system from the matter in neighboring star systems and the interstellar medium . The interstellar medium is the space between star systems. The solar wind, having traveled billions of kilometers, cannot extend beyond the interstellar medium. Studying the Sun The sun has not always been a subject of scientific discovery and inquiry. For thousands of years, the sun was known in cultures all over the world as a god, a goddess, and a symbol of life. To the ancient Aztecs, the sun was a powerful deity known as Tonatiuh, who required human sacrifice to travel across the sky. In Baltic mythology, the sun was a goddess named Saule, who brought fertility and health. Chinese mythology held that the sun is the only remaining of 10 sun gods. In 150 B.C.E., Greek scholar Claudius Ptolemy created a geocentric model of the solar system in which the moon, planets, and sun revolved around Earth. It was not until the 16th century that Polish astronomer Nicolaus Copernicus used mathematical and scientific reasoning to prove that planets rotated around the sun. This heliocentric model is the one we use today. In the 17th century, the telescope allowed people to examine the sun in detail. The sun is much too bright to allow us to study it with our eyes unprotected. With a telescope, it was possible for the first time to project a clear image of the sun onto a screen for examination. English scientist Sir Isaac Newton used a telescope and prism to scatter the light of the sun, and proved that sunlight was actually made of a spectrum of colors. In 1800, infrared and ultraviolet light were discovered to exist just outside of the visible spectrum. An optical instrument called a spectroscope made it possible to separate visible light and other electromagnetic radiation into its various wavelengths. Spectroscopy also helped scientists identify gases in the sun’s atmosphere—each element has its own wavelength pattern. However, the method by which the sun generated its energy remained a mystery. Many scientists hypothesized that the sun was contracting, and emitting heat from that process. In 1868, English astronomer Joseph Norman Lockyer was studying the sun’s electromagnetic spectrum. He observed bright lines in the photosphere that did not have a wavelength of any known element on Earth. He guessed that there was an element isolated on the sun, and named it helium after the Greek sun god, Helios. Over the next 30 years, astronomers concluded that the sun had a hot, pressurized core that was capable of producing massive amounts of energy through nuclear fusion. Technology continued to improve and allowed scientists to uncover new features of the sun. Infrared telescopes were invented in the 1960s, and scientists observed energy outside the visible spectrum. Twentieth-century astronomers used balloons and rockets to send specialized telescopes high above Earth, and examined the sun without any interference from Earth's atmosphere. Solrad 1 was the first spacecraft designed to study the sun, and was launched by the United States in 1960. That decade, NASA sent five Pioneer satellites to orbit the sun and collect information about the star. In 1980, NASA launched a mission during the solar maximum to gather information about the high-frequency gamma rays, UV rays, and x-rays that are emitted during solar flares. The Solar and Heliospheric Observatory ( SOHO ) was developed in Europe and put into orbit in 1996 to collect information. SOHO has been successfully collecting data and forecasting space weather for 12 years. Voyager 1 and 2 are spacecraft traveling to the edge of the heliosphere to discover what the atmosphere is made of where solar wind meets the interstellar medium. Voyager 1 crossed this boundary in 2012 and Voyager 2 did so in 2018. Another development in the study of the sun is helioseismology , the study of solar waves. The turbulence of the convective zone is hypothesized to contribute to solar waves that continuously transmit solar material to the outer layers of the sun. By studying these waves, scientists understand more about the sun’s interior and the cause of solar activity. Energy from the Sun Photosynthesis

Sunlight provides necessary light and energy to plants and other producers in the food web . These producers absorb the sun’s radiation and convert it into energy through a process called photosynthesis. Producers are mostly plants (on land) and algae (in aquatic regions). They are the foundation of the food web, and their energy and nutrients are passed on to every other living organism. Fossil Fuels Photosynthesis is also responsible for all of the fossil fuels on Earth. Scientists estimate that about three billion years ago, the first producers evolved in aquatic settings. Sunlight allowed plant life to thrive and adapt. After the plants died, they decomposed and shifted deeper into the earth, sometimes thousands of meters. This process continued for millions of years. Under intense pressure and high temperatures, these remains became what we know as fossil fuels. These microorganisms became petroleum, natural gas, and coal. People have developed processes for extracting these fossil fuels and using them for energy. However, fossil fuels are a nonrenewable resource . They take millions of years to form. Solar Energy Technology Solar energy technology harnesses the sun’s radiation and converts it into heat, light, or electricity. Solar energy is a renewable resource , and many technologies can harvest it directly for use in homes, businesses, schools, and hospitals. Some solar energy technologies include solar voltaic cells and panels, solar thermal collectors, solar thermal electricity, and solar architecture . Photovoltaics use the sun’s energy to speed up electrons in solar cells and generate electricity. This form of technology has been used widely, and can provide electricity for rural areas, large power stations, buildings, and smaller devices such as parking meters and trash compactors. The sun’s energy can also be harnessed by a method called “concentrated solar power,” in which the sun’s rays are reflected and magnified by mirrors and lenses. The intensified ray of sunlight heats a fluid, which creates steam and powers an electric generator . Solar power can also be collected and distributed without machinery or electronics. For example, roofs can be covered with vegetation or painted white to decrease the amount of heat absorbed into the building, thereby decreasing the amount of electricity needed for air conditioning. This is solar architecture. Sunlight is abundant: In one hour, Earth’s atmosphere receives enough sunlight to power the electricity needs of all people for a year. However, solar technology is expensive, and depends on sunny and cloudless local weather to be effective. Methods of harnessing the sun’s energy are still being developed and improved.

Like a Diamond in the Sky White dwarf stars are made of crystallized carbon diamond. A typical white dwarf is about 10 billion trillion trillion carats. In about five billion years, says Travis Metcalfe of the Harvard-Smithsonian Center for Astrophysics, our sun will become a diamond that truly is forever.

Solar Constant The solar constant is the average amount of solar energy reaching Earth's atmosphere. The solar constant is about 1.37 kilowatts of electricity per square meter.

Solarmax 2013 will bring the next solar maximum (solarmax), a period astronomers say will bring more solar flares, coronal mass ejections, solar storms, and auroras.

Sun is the Loneliest Number The sun is pretty isolated, way out on the inner rim of the Orion Arm of the Milky Way. Its nearest stellar neighbor, a red dwarf named Proxima Centauri, is about 4.24 light-years away.

Sunny Days at Space Agencies NASA and other space agencies have more than a dozen heliophysics missions, which study the sun, heliosphere, and planetary environments as a single connected system. A few of the ongoing missions are: ACE : observing particles of solar, interplanetary, interstellar, and galactic origins AIM : determining the causes of the highest-altitude clouds in Earths atmosphere Hinode : studying the sun with the worlds highest-resolution solar telescopes IBEX : mapping the entire boundary of the solar system RHESSI : researching gamma rays and X-rays, the most powerful energy emitted by the sun SOHO : understanding the structure and dynamics of the sun SDO : a crown jewel of NASA, aimed at developing the scientific understanding necessary to address those aspects of the sun and solar system that directly affect life and society STEREO : understanding coronal mass ejections Voyager : studying space at the edge of the solar system Wind : understanding the solar wind

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Why Do Planets Orbit The Sun? (Explained!)

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There is a balance between the gravitational force of the Sun and the planets, which causes them to orbit. The planets are not just going around in circles. They are moving in ellipses, which means they move closer to and farther away from the Sun as they orbit.

Continue reading to discover how the planets orbit the Sun and whether they all follow a circular path. Learn what an ecliptic plane is, why the solar system is heliocentric, and the answers to many more of your orbital questions.

How Do Planets Orbit The Sun?

Table of Contents

The Milky Way formed from a rotating cloud filled with dust and gas; in the center, our Sun began to form. Each planet was created within the rotating disc with a momentum that continues today. The planets maintain their orbits because no other force in our Solar System can stop them.

The Sun sits at the center of the Milky Way. It has a gravitational pull on all the planets and other things that orbit it. The planets’ orbits are shaped like ellipses, which means they are not circles around the Sun. The perihelion is the point in a planet’s orbit at which it is closest to the Sun ; the aphelion is the point when it is farthest away.

The reason why the solar system is heliocentric is because of gravity. The Sun; possesses a far greater mass than any of the planets, so it exerts a greater gravitational pull on them.

Do All Planets Orbit The Sun In A Circular Pattern?

No, not all planets orbit the Sun in a circular pattern. Each planet orbits the Sun via an elliptical pattern, some to a more considerable degree (or eccentricity) than others. A circular orbit is an orbit in which the object follows a circular path around a central point.

Objects in circular orbits are often not at the same distance from the central point. The shape of their orbit is determined by their relative speed and the gravitational force of attraction between them and the central point.

The planets with the least eccentric orbit (and are, therefore, the closest to a circular orbit) are Neptune, Venus, and Earth.

An elliptical orbit is an orbit in which the orbiting object follows a path that looks more like an oval. In an elliptical orbit, the orbiting object is not always at the same distance from the center of gravity.

The shape of an elliptical orbit can be described as a flattened circle or oval. It is also possible for other shapes to be created, such as two circles overlapping or one circle with another circle inside. The planets that have the most eccentric orbit are Mercury and Pluto.

Why Don’t Planets Get Closer To The Sun When Orbiting It?

Planets and stars are held in their orbits by a force called gravity. Gravity keeps Earth from flying off into space and keeps the moon in orbit around us. It requires significant energy to get an object to move away from a planet or star and even more energy to move closer to another planet or star.

The Earth and other planets in the solar system orbit around the Sun; this orbit relies on a set of physical forces that continuously fight against the laws of motion.

A planet’s momentum makes them want to continue its path of travel in a straight line, but the gravity of the Sun prevents this and pulls the orbiting body closer. As the planet moves closer to the Sun, it gains enough additional speed to pull away slightly; still, once it moves away, it loses momentum, slows down, and is drawn closer to the Sun once more.

This continuous process keeps the planets in orbit, which is why planets don’t get closer (overall) to the Sun when they orbit it.

Do The Planets Orbit The Sun On A Flat Plane?

The ecliptic plane is a flat surface in the sky that the planets travel on; its incline sits at 23.5 degrees from Earth’s equator. All planets, asteroids, comets, and other objects in our solar system orbit around this plane.

In astronomy, an ecliptic is a great circle on Earth’s celestial sphere (i.e., its surface) that marks where the Sun appears to be moving across the sky each day for an observer who lives at Earth’s equator.

The orbits of the planets are elliptical, meaning they are not circular but rather long ovals with two foci—each path and a more or less pronounced eccentricity, which is the deviation from a perfect circle. The eccentricity of a planet’s orbit ranges from zero to one, where one is a straight line, and zero is a perfect circle.

Venus has the least eccentric orbit with a score of 0.007, while Mercury has the highest eccentricity at 0.2056 .

But, most of them have their orbits tilted at an angle to our line of sight from Earth. This means that they don’t orbit on the same plane as we see them from Earth – which is why some planets can be seen in our night sky while others cannot.

Our solar system is heliocentric thanks to the massive pull of gravity exerted by the Sun. Just as Earth’s gravity helps to maintain the orbit of satellites such as the moon, the Sun provides the same stable force for our planets. They do not fall into this massive star because they travel fast enough to “miss” it and fall around the Sun as a continuous orbit.

How do the planets stay in orbit around the Sun? | Cool Cosmos (caltech.edu)

| How Things Fly (si.edu)

Why do planets orbit the Sun but don’t get closer to it? – Quora

Orbits and the Ecliptic Plane (gsu.edu)

Do Planets Orbit The Sun In Perfect Circles? (EXPLAINED!)
Can Planets Orbit Black Holes? (EXPLAINED!)
Do Planets Orbit The Sun At The Same Speed? (Answered!)
Can Black Holes Orbit Each Other? (EXPLAINED!)
Why Are Inner Planets Rocky? (Explained!)
Do All Planets Have Cores? (EXPLAINED!)

How many times has Earth orbited the sun?

We worked out how many trips each of the solar system's eight planets has taken around the sun over the past 4.6 billion years.

An illustration of the solar system and the planet's orbits around the sun

When you're standing on Earth's surface, it's easy to forget that our planet is hurtling around the sun at more than 67,000 mph (107,800 km/h) . And it's even easier to forget that there are seven other planets also making their way around our home star at similar breakneck speeds, or that all eight have been ceaselessly circling the solar system for billions of years.

But what might really blow your mind is finding out how many trips around the sun each planet has under its belt. This may seem like a tricky thing to calculate, but because the planets' orbits have remained largely unaltered for most of their existence, all it takes is a bit of basic math.

Related: What's the maximum number of planets that could orbit the sun?

The solar system was born around 4.6 billion years ago, when the sun began to form from a cloud of dust left behind by prior stellar explosions. Around 4.59 billion years ago, the giant planets — Jupiter , Saturn , Uranus and Neptune — were born. And around 4.5 billion years ago, the smaller, rocky planets — Mercury , Venus , Earth and Mars — took shape, according to The Planetary Society .

But when the planets were born, their orbits around the sun were not the same as they are today (especially those of the giant planets). For around 100 million years after the first planets formed, there was a " dynamical instability " among them, which resulted in a gravitational tug-of-war between these large bodies and caused the rest of the outer solar system's planetary material, and even some emerging protoplanets, to be catapulted out of the solar system, Sean Raymond , an astronomer at the Bordeaux Astrophysics Laboratory in France and an expert on planetary systems, told Live Science in an email.

However, once all of the planets had emerged and finished jostling with one another for their positions, they settled into consistent, stable orbits that haven't changed much since.

— What would colors look like on other planets?

— What is the coldest place in the solar system?

— What if Earth shared its orbit with another planet?

"For 98% to 99% of the solar system's lifetime, the planets' orbits have been nice and stable," Raymond said. As a result, you can use the planets' current orbital dynamics to make a pretty accurate guess at how many trips they have made around the sun, he added.

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Take Earth, for example. Our planet takes a year to orbit the sun and has existed for 4.5 billion years, so it has taken roughly 4.5 billion trips around the solar system.

However, the number of total orbits varies greatly among the other planets because their years are either shorter or longer than Earth's.

Earth and the moon with the sun in the background

Mercury, the closest planet to the sun, takes only 88 days (or roughly 0.24 years, based on a year with 365.25 days) to travel around the sun once. So, over the past 4.5 billion years, it has completed around 18.7 billion solar orbits. But Neptune, the farthest planet from the sun, takes around 60,190 days (or 164.7 years) to complete an orbit, which means it has managed only about 27.9 million trips around the sun during its 4.59 billion years of existence. That means Mercury has orbited the sun around 18.7 billion times more than Neptune has.

Here is the full list of the planets, their year length and their total number of trips around the sun:

These sound like impressive numbers (and they are) but most of the planets could potentially double their number of orbits in their remaining lifetimes.

In around 4.5 billion years, the sun will have swollen outward to reach Earth's orbit and transition into a red dwarf star, which will destroy Mercury, Venus and Earth. The other planets may live on for a time if they are not burned up but their orbits will likely be majorly altered.

Harry is a U.K.-based senior staff writer at Live Science. He studied marine biology at the University of Exeter before training to become a journalist. He covers a wide range of topics including space exploration, planetary science, space weather, climate change, animal behavior, evolution and paleontology. His feature on the upcoming solar maximum was shortlisted in the "top scoop" category at the National Council for the Training of Journalists (NCTJ) Awards for Excellence in 2023.

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raid2506 An informative article, thank you. It also made me wonder why I've not thought of it like that before? As an aside, the penultimate word in the article "majorly" is an informal slang term and I question it's use in an otherwise balanced and informative piece 🤔. Reply
chaz1252 I don't care how many scientists agree on the age of our planet, there is no way to know. they can guess which is what they are doing. They may know a lot about this great orb circling our star but they will never know everything. Reply

admin said: We worked out how many trips each of the solar system's eight planets has taken around the sun over the past 4.6 billion years. How many times has Earth orbited the sun? : Read more

rocksnstars In around 4.5 billion years, the sun will ... transition into a red giant star, not a red dwarf. Reply
Pawel50 Ziemia okrąża Słońce raz w ciągu jednego roku. Dziesięć regularnych zastosowań orbitalnych trwa około 365,25 dni, co stanowi dla naszego kalendarza rocznego. To tylko liczba obiegów wokół Słońca determinuje zmianę pory roku i inne cykle astronomiczne, które spotykają się w życiu na naszej planecie.:) Reply
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3.1 The Laws of Planetary Motion

Learning objectives.

By the end of this section, you will be able to:

Describe how Tycho Brahe and Johannes Kepler contributed to our understanding of how planets move around the Sun
Explain Kepler’s three laws of planetary motion

Tycho Brahe’s Observatory

Three years after the publication of Copernicus’ De Revolutionibus , Tycho Brahe was born to a family of Danish nobility. He developed an early interest in astronomy and, as a young man, made significant astronomical observations. Among these was a careful study of what we now know was an exploding star that flared up to great brilliance in the night sky. His growing reputation gained him the patronage of the Danish King Frederick II, and at the age of 30, Brahe was able to establish a fine astronomical observatory on the North Sea island of Hven ( Figure 3.2 ). Brahe was the last and greatest of the pre-telescopic observers in Europe.

Johannes Kepler

Johannes Kepler was born into a poor family in the German province of Württemberg and lived much of his life amid the turmoil of the Thirty Years’ War (see Figure 3.2 ). He attended university at Tubingen and studied for a theological career. There, he learned the principles of the Copernican system and became converted to the heliocentric hypothesis. Eventually, Kepler went to Prague to serve as an assistant to Brahe, who set him to work trying to find a satisfactory theory of planetary motion—one that was compatible with the long series of observations made at Hven. Brahe was reluctant to provide Kepler with much material at any one time for fear that Kepler would discover the secrets of the universal motion by himself, thereby robbing Brahe of some of the glory. Only after Brahe’s death in 1601 did Kepler get full possession of the priceless records. Their study occupied most of Kepler’s time for more than 20 years.

The First Two Laws of Planetary Motion

This property suggests a simple way to draw an ellipse ( Figure 3.4 ). We wrap the ends of a loop of string around two tacks pushed through a sheet of paper into a drawing board, so that the string is slack. If we push a pencil against the string, making the string taut, and then slide the pencil against the string all around the tacks, the curve that results is an ellipse. At any point where the pencil may be, the sum of the distances from the pencil to the two tacks is a constant length—the length of the string. The tacks are at the two foci of the ellipse.

Kepler’s second law deals with the speed with which each planet moves along its ellipse, also known as its orbital speed . Working with Brahe’s observations of Mars, Kepler discovered that the planet speeds up as it comes closer to the Sun and slows down as it pulls away from the Sun. He expressed the precise form of this relationship by imagining that the Sun and Mars are connected by a straight, elastic line. When Mars is closer to the Sun (positions 1 and 2 in Figure 3.5 ), the elastic line is not stretched as much, and the planet moves rapidly. Farther from the Sun, as in positions 3 and 4, the line is stretched a lot, and the planet does not move so fast. As Mars travels in its elliptical orbit around the Sun, the elastic line sweeps out areas of the ellipse as it moves (the colored regions in our figure). Kepler found that in equal intervals of time (t), the areas swept out in space by this imaginary line are always equal; that is, the area of the region B from 1 to 2 is the same as that of region A from 3 to 4.

Link to Learning

The Kepler's Second Law demonstrator from CCNY's ScienceSims project shows how an orbiting planet sweeps out the same area in the same time.

Kepler’s Third Law

Example 3.1

Calculating periods.

If the object’s orbit has a semimajor axis of 50 AU ( a = 50), we can cube 50 and then take the square root of the result to get P:

Therefore, the orbital period of the object is about 350 years. This would place our hypothetical object beyond the orbit of Pluto.

Check Your Learning

P = 3 × 3 × 3 = 27 = 5.2 years P = 3 × 3 × 3 = 27 = 5.2 years

Kepler’s three laws of planetary motion can be summarized as follows:

Kepler’s first law : Each planet moves around the Sun in an orbit that is an ellipse, with the Sun at one focus of the ellipse.
Kepler’s second law : The straight line joining a planet and the Sun sweeps out equal areas in space in equal intervals of time.
Kepler’s third law : The square of a planet’s orbital period is directly proportional to the cube of the semimajor axis of its orbit.

Example 3.2

Applying kepler’s third law.

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Book title: Astronomy 2e
Publication date: Mar 9, 2022
Location: Houston, Texas
Book URL: https://openstax.org/books/astronomy-2e/pages/1-introduction
Section URL: https://openstax.org/books/astronomy-2e/pages/3-1-the-laws-of-planetary-motion

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How Long is a Year on Other Planets?

Here is how long it takes each of the planets in our solar system to orbit around the Sun (in Earth days):

A year on Earth is approximately 365 days. Why is that considered a year? Well, 365 days is about how long it takes for Earth to orbit all the way around the Sun one time.

Image of the Earth with the Sun behind it.

A year is measured by how long it takes a planet to orbit around its star. Earth orbits around the Sun in approximately 365 days. Credit: NASA/Terry Virts

It’s not exactly this simple though. An Earth year is actually about 365 days, plus approximately 6 hours. Read more about that here .

All of the other planets in our solar system also orbit the Sun. So, how long is a year on those planets? Well, it depends on where they are orbiting!

Planets that orbit closer to the Sun than Earth have shorter years than Earth. Planets that orbit farther from the Sun than Earth have longer years than Earth.

A planet orbiting close to its star has a shorter year than a planet orbiting farther from its star. Credit: NASA/JPL-Caltech

This happens for two main reasons.

If a planet is close to the Sun, the distance it orbits around the Sun is fairly short. This distance is called an orbital path .
The closer a planet travels to the Sun, the more the Sun’s gravity can pull on the planet. The stronger the pull of the Sun’s gravity, the faster the planet orbits.

Check out how long a year is on each planet below!

Year: 88 Earth Days Distance from Sun: ~35 million miles (58 million km)

Year: 225 Earth Days Distance from Sun: ~67 million miles (108 million km)

Year: 365 Earth Days Distance from Sun: ~93 million miles (150 million km)

Year: 687 Earth Days Distance from Sun: ~142 million miles (228 million km)

Year: 4,333 Earth Days Distance from Sun: ~484 million miles (778 million km)

Year: 10,759 Earth Days Distance from Sun: ~887 million miles (1.43 billion km)

Year: 30,687 Earth Days Distance from Sun: ~1.78 billion miles (2.87 billion km)

Year: 60,190 Earth Days Distance from Sun: ~2.80 billion miles (4.5 billion km)

Why does NASA care about years on other planets?

NASA needs to know how other planets orbit the Sun because it helps us travel to those planets! For example, if we want a spacecraft to safely travel to another planet, we have to make sure we know where that planet is in its orbit. And we also have to make sure we don’t run into any other orbiting objects — like planets or asteroids — along the way.

Scientists who study Mars also need to keep a Martian calendar to schedule what rovers and landers will be doing and when.

Mars and Earth are always moving. So, if we want to land a robotic explorer on Mars, we have to understand how Earth and Mars orbit the Sun. Watch this video to learn more about the Martian year. Credit: NASA/JPL-Caltech

*Length of year on other planets calculated from data on the NASA Solar System Dynamics website .

If you liked this, you may like:

Moons and rings

All of the planets travel around the Sun in a counter-clockwise direction – as seen from above Earth’s north pole. Their year - the time they take to complete one orbit - varies with their distance from the Sun. A year on Mercury lasts for just 88 Earth days, so someone born there would have four times as many birthdays as we do on Earth. In contrast, a year on Pluto is equal to 248 of our years. Someone born on Pluto would never celebrate a birthday!

Venus and Mercury have no natural satellites, but the other seven planets all have moons going around them. The total number so far recorded is 138. Most of the moons are very small and difficult to see, even with big telescopes. At present, the record holder is Jupiter, with 63 known satellites. These include four planet-sized moons – Ganymede (the largest satellite in the Solar System), Callisto, Europa and Io.

The strong gravity of the other gas giants has also gathered large numbers of followers: Saturn has 31, Uranus 27 and Neptune 13. Both the Earth and Pluto are orbited by one large moon.

The four largest planets - Jupiter, Saturn, Uranus and Neptune -also have rings. They are made of pieces of ice and rock ranging from in size from mountains to cigarette smoke. The rings may be left-overs from a moon that broke apart, or pieces that have been chipped off nearby moons.

Birth of the Moon
Moon eclipses
Moon phases

Orbital Speed of Planets in Order

The orbital speeds of the planets vary depending on their distance from the sun. This is because of the gravitational force being exerted on the planets by the sun. Additionally, according to Kepler’s laws of planetary motion, the flight path of every planet is in the shape of an ellipse. Below is a list of the planet’s orbital speeds in order from fastest to slowest.

1. Mercury is the fastest planet, which speeds around the sun at 47.87 km/s. In miles per hour this equates to a whopping 107,082 miles per hour.

2. Venus is the second fastest planet with an orbital speed of 35.02 km/s, or 78,337 miles per hour.

3. Earth , our home planet of Earth speeds around the sun at a rate of 29.78 km/s. This means that we are traveling at 66,615 miles per hour.

4. Mars , with an orbital speed of 24.077 km/s, or 53,858 miles per hour, travels considerably faster than the prior planets.

5. Jupiter travels a bit faster than the previous three planets with an orbital speed of 13.07 km/s. This translates to approximately 29,236 miles per hour.

6. Saturn travels at 9.69 km/s, or 21,675 miles per hour, which makes it the third slowest planet.

7. Uranus is the second slowest planet with an orbital speed of 6.81 km/s. This equates to 15,233 miles per hour.

8. Neptune travels around the sun at a speed of 5.43 km/s or 12,146 miles per hour. Although this is a very high rate of speed, Neptune still has the slowest orbital velocity of any of the planets.

Planet Where It's Sunny Every Day Spotted 280 Light-Years Away

A stronomers have mapped the weather on a planet hundreds of light years away, and found that it always has clear skies on the side facing its sun.

This distant exoplanet, named WASP-43 b, is a hot gas giant orbiting a star around 280 light years away from our solar system, and dramatic weather patterns have been detected, including winds of up to 5,000 mph at its equator, according to a new paper in the journal Nature Astronomy.

This far-off mapping of the planet's weather was made possible thanks to the power of the James Webb Space Telescope (JWST), which is able to measure variations in temperatures and the gases in the atmosphere of exoplanets many billions of miles away from Earth.

WASP-43 b is a "hot Jupiter" type planet with an atmosphere mostly made from hydrogen, water, and helium. It orbits its star (named WASP-43) at a very close 1.3 million miles, only 4 percent of the distance between our sun and its closest planet, Mercury. The close proximity to its star has led to it becoming tidally locked, which means one side always faces toward the star and the other always faces away—just like the moon orbiting the Earth.

"With Hubble, we could clearly see that there is water vapor on the dayside. Both Hubble and Spitzer suggested there might be clouds on the nightside," study co-author Taylor Bell, a researcher from the Bay Area Environmental Research Institute and the NASA Ames Research Center, said in a statement.

"But we needed more precise measurements from JWST to really begin mapping the temperature, cloud cover, winds, and more detailed atmospheric composition all the way around the planet."

Now, the JWST has spied the weather patterns on this distant world, confirming that it has only water vapor and no clouds on its day side, high-up and thick clouds on its night side, and powerful winds around its equator mixing gases between the two sides.

"JWST is a game changer for studying exoplanet atmospheres, and in less than two years of science operations we have already learned so much," co-author Joanna Barstow, a research fellow at the Open University, said in the statement.

These discoveries were made by watching the star as the planet passed in front of it during its rapid 19.5-hour orbit around its sun. JWST's infrared system was used to measure light from the star every 10 seconds across 24 hours.

"By observing over an entire orbit, we were able to calculate the temperature of different sides of the planet as they rotate into view," said Bell. "From that, we could construct a rough map of temperature across the planet."

The researchers found that the day side of the planet was hot enough to melt iron at a staggering 2,282 degrees F, while the night side was a much milder 1,112 degrees F. They then used 3D atmospheric models to calculate the likely weather on the planet, finding that the night side was probably covered in thick clouds, while the day side was clear-skied.

"JWST has given us an opportunity to figure out exactly which molecules we're seeing," said Barstow.

They also found that there were traces of water vapor on both the day and night sides, but there was little to no methane present in the atmosphere of the planet.

"The fact that we don't see methane tells us that WASP-43b must have wind speeds reaching something like 5,000 miles per hour," explained Barstow. "If winds move gas around from the dayside to the nightside and back again fast enough, there isn't enough time for the expected chemical reactions to produce detectable amounts of methane on the nightside."

Thanks to this powerful wind, it's likely that the atmosphere is made up of the same elements all the way around the planet.

Do you have a tip on a science story that Newsweek should be covering? Do you have a question about exoplanets? Let us know via [email protected].

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Artist's impression of WASP-43. This far-off exoplanet has powerful winds and extreme weather.

Jupiter Facts

Jupiter is a world of extremes. It's the largest planet in our solar system – if it were a hollow shell, 1,000 Earths could fit inside. It's also the oldest planet, forming from the dust and gases left over from the Sun's formation 4.5 billion years ago. But it has the shortest day in the solar system, taking only 10.5 hours to spin around once on its axis.

Introduction

Jupiter's signature stripes and swirls are actually cold, windy clouds of ammonia and water, floating in an atmosphere of hydrogen and helium. The dark orange stripes are called belts, while the lighter bands are called zones, and they flow east and west in opposite directions. Jupiter’s iconic Great Red Spot is a giant storm bigger than Earth that has raged for hundreds of years.

The king of planets was named for Jupiter, king of the gods in Roman mythology. Most of its moons are also named for mythological characters, figures associated with Jupiter or his Greek counterpart, Zeus.

Jupiter, being the biggest planet, gets its name from the king of the ancient Roman gods.

Potential for Life

Jupiter’s environment is probably not conducive to life as we know it. The temperatures, pressures, and materials that characterize this planet are most likely too extreme and volatile for organisms to adapt to.

While planet Jupiter is an unlikely place for living things to take hold, the same is not true of some of its many moons. Europa is one of the likeliest places to find life elsewhere in our solar system. There is evidence of a vast ocean just beneath its icy crust, where life could possibly be supported.

Size and Distance

With a radius of 43,440.7 miles (69,911 kilometers), Jupiter is 11 times wider than Earth. If Earth were the size of a grape, Jupiter would be about as big as a basketball.

From an average distance of 484 million miles (778 million kilometers), Jupiter is 5.2 astronomical units away from the Sun. One astronomical unit (abbreviated as AU), is the distance from the Sun to Earth. From this distance, it takes sunlight 43 minutes to travel from the Sun to Jupiter.

Illustration showing Jupiter's position in the solar system relative to Earth and the Sun.

Orbit and Rotation

Jupiter has the shortest day in the solar system. One day on Jupiter takes only about 10 hours (the time it takes for Jupiter to rotate or spin around once), and Jupiter makes a complete orbit around the Sun (a year in Jovian time) in about 12 Earth years (4,333 Earth days).

Its equator is tilted with respect to its orbital path around the Sun by just 3 degrees. This means Jupiter spins nearly upright and does not have seasons as extreme as other planets do.

With four large moons and many smaller moons, Jupiter forms a kind of miniature solar system.

Jupiter has 95 moons that are officially recognized by the International Astronomical Union. The four largest moons – Io, Europa, Ganymede, and Callisto – were first observed by the astronomer Galileo Galilei in 1610 using an early version of the telescope. These four moons are known today as the Galilean satellites, and they're some of the most fascinating destinations in our solar system.

Io is the most volcanically active body in the solar system. Ganymede is the largest moon in the solar system (even bigger than the planet Mercury). Callisto’s very few small craters indicate a small degree of current surface activity. A liquid-water ocean with the ingredients for life may lie beneath the frozen crust of Europa, the target of NASA's Europa Clipper mission slated to launch in 2024.

› More on Jupiter's Moons

Discovered in 1979 by NASA's Voyager 1 spacecraft, Jupiter's rings were a surprise. The rings are composed of small, dark particles, and they are difficult to see except when backlit by the Sun. Data from the Galileo spacecraft indicate that Jupiter's ring system may be formed by dust kicked up as interplanetary meteoroids smash into the giant planet's small innermost moons.

Jupiter took shape along with rest of the solar system about 4.5 billion years ago. Gravity pulled swirling gas and dust together to form this gas giant. Jupiter took most of the mass left over after the formation of the Sun, ending up with more than twice the combined material of the other bodies in the solar system. In fact, Jupiter has the same ingredients as a star, but it did not grow massive enough to ignite.

About 4 billion years ago, Jupiter settled into its current position in the outer solar system, where it is the fifth planet from the Sun.

The composition of Jupiter is similar to that of the Sun – mostly hydrogen and helium. Deep in the atmosphere, pressure and temperature increase, compressing the hydrogen gas into a liquid. This gives Jupiter the largest ocean in the solar system – an ocean made of hydrogen instead of water. Scientists think that, at depths perhaps halfway to the planet's center, the pressure becomes so great that electrons are squeezed off the hydrogen atoms, making the liquid electrically conducting like metal. Jupiter's fast rotation is thought to drive electrical currents in this region, generating the planet's powerful magnetic field. It is still unclear if deeper down, Jupiter has a central core of solid material or if it may be a thick, super-hot and dense soup. It could be up to 90,032 degrees Fahrenheit (50,000 degrees Celsius) down there, made mostly of iron and silicate minerals (similar to quartz).

As a gas giant, Jupiter doesn’t have a true surface. The planet is mostly swirling gases and liquids. While a spacecraft would have nowhere to land on Jupiter, it wouldn’t be able to fly through unscathed either. The extreme pressures and temperatures deep inside the planet crush, melt, and vaporize spacecraft trying to fly into the planet.

Jupiter's appearance is a tapestry of colorful cloud bands and spots. The gas planet likely has three distinct cloud layers in its "skies" that, taken together, span about 44 miles (71 kilometers). The top cloud is probably made of ammonia ice, while the middle layer is likely made of ammonium hydrosulfide crystals. The innermost layer may be made of water ice and vapor.

The vivid colors you see in thick bands across Jupiter may be plumes of sulfur and phosphorus-containing gases rising from the planet's warmer interior. Jupiter's fast rotation – spinning once every 10 hours – creates strong jet streams, separating its clouds into dark belts and bright zones across long stretches.

With no solid surface to slow them down, Jupiter's spots can persist for many years. Stormy Jupiter is swept by over a dozen prevailing winds, some reaching up to 335 miles per hour (539 kilometers per hour) at the equator. The Great Red Spot, a swirling oval of clouds twice as wide as Earth, has been observed on the giant planet for more than 300 years. More recently, three smaller ovals merged to form the Little Red Spot, about half the size of its larger cousin.

Findings from NASA’s Juno probe released in October 2021 provide a fuller picture of what’s going on below those clouds. Data from Juno shows that Jupiter’s cyclones are warmer on top, with lower atmospheric densities, while they are colder at the bottom, with higher densities. Anticyclones, which rotate in the opposite direction, are colder at the top but warmer at the bottom.

The findings also indicate these storms are far taller than expected, with some extending 60 miles (100 kilometers) below the cloud tops and others, including the Great Red Spot, extending over 200 miles (350 kilometers). This surprising discovery demonstrates that the vortices cover regions beyond those where water condenses and clouds form, below the depth where sunlight warms the atmosphere.

The height and size of the Great Red Spot mean the concentration of atmospheric mass within the storm potentially could be detectable by instruments studying Jupiter’s gravity field. Two close Juno flybys over Jupiter’s most famous spot provided the opportunity to search for the storm’s gravity signature and complement the other results on its depth.

With their gravity data, the Juno team was able to constrain the extent of the Great Red Spot to a depth of about 300 miles (500 kilometers) below the cloud tops.

Belts and Zones In addition to cyclones and anticyclones, Jupiter is known for its distinctive belts and zones – white and reddish bands of clouds that wrap around the planet. Strong east-west winds moving in opposite directions separate the bands. Juno previously discovered that these winds, or jet streams, reach depths of about 2,000 miles (roughly 3,200 kilometers). Researchers are still trying to solve the mystery of how the jet streams form. Data collected by Juno during multiple passes reveal one possible clue: that the atmosphere’s ammonia gas travels up and down in remarkable alignment with the observed jet streams.

Juno’s data also shows that the belts and zones undergo a transition around 40 miles (65 kilometers) beneath Jupiter’s water clouds. At shallow depths, Jupiter’s belts are brighter in microwave light than the neighboring zones. But at deeper levels, below the water clouds, the opposite is true – which reveals a similarity to our oceans.

Polar Cyclones Juno previously discovered polygonal arrangements of giant cyclonic storms at both of Jupiter’s poles – eight arranged in an octagonal pattern in the north and five arranged in a pentagonal pattern in the south. Over time, mission scientists determined these atmospheric phenomena are extremely resilient, remaining in the same location.

Juno data also indicates that, like hurricanes on Earth, these cyclones want to move poleward, but cyclones located at the center of each pole push them back. This balance explains where the cyclones reside and the different numbers at each pole.

Magnetosphere

The Jovian magnetosphere is the region of space influenced by Jupiter's powerful magnetic field. It balloons 600,000 to 2 million miles (1 to 3 million kilometers) toward the Sun (seven to 21 times the diameter of Jupiter itself) and tapers into a tadpole-shaped tail extending more than 600 million miles (1 billion kilometers) behind Jupiter, as far as Saturn's orbit. Jupiter's enormous magnetic field is 16 to 54 times as powerful as that of the Earth. It rotates with the planet and sweeps up particles that have an electric charge. Near the planet, the magnetic field traps swarms of charged particles and accelerates them to very high energies, creating intense radiation that bombards the innermost moons and can damage spacecraft.

Jupiter's magnetic field also causes some of the solar system's most spectacular aurorae at the planet's poles.

Discover More Topics From NASA

Tendrils of hot plasma stream from the Sun.

Asteroids, Comets & Meteors

Kuiper Belt

Illustration of spacecraft near a giant space rock far from the Sun.

IMAGES

Planets on orbits around sun solar system Vector Image
Solar System—Orbits
Diagram of Planets in the Solar System 1132887 Vector Art at Vecteezy
Eight solar system planets orbiting the sun diagram Vector educational
Solar system with sun and planets on orbit universe starry sky By
Planets in Order from the Sun

VIDEO

Space Travel: Let's Explore Our Solar System and Planets
Exploring Planets: Our Solar System's Marvelous Worlds
How Planets revolve around Sun
planets from the Sun Song/Distance between planets to the Sun
Our Planets In Our Solar System
PLANETS AROUND THE SUN (SeeMore Reader)

COMMENTS

Our Solar System
Planets, asteroids, and comets orbit our Sun. They travel around our Sun in a flattened circle called an ellipse. It takes the Earth one year to go around the Sun. Mercury goes around the Sun in only 88 days. It takes Pluto, the most famous dwarf planet, 248 years to make one trip around the Sun.
In Depth
Introduction. The planetary system we call home is located in an outer spiral arm of the Milky Way galaxy. Our solar system consists of our star, the Sun, and everything bound to it by gravity - the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune; dwarf planets such as Pluto; dozens of moons; and millions of asteroids, comets, and meteoroids.
Solar System Exploration
Our solar system orbits the center of the galaxy at about 515,000 mph (828,000 kph). It takes about 230 million years to complete one orbit around the galactic center. We call it the solar system because it is made up of our star, the Sun, and everything bound to it by gravity - the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus ...
Understanding Kepler's Laws of Planetary Motion
Copernicus had put forth the theory that the planets travel in a circular path around the Sun. This heliocentric theory had the advantage of being much simpler than the previous theory, which held that the planets revolve around Earth. However, Kepler's employer, Tycho, had taken very accurate observations of the planets and found that ...
Orbits and Kepler's Laws
Kepler's First Law: each planet's orbit about the Sun is an ellipse. The Sun's center is always located at one focus of the orbital ellipse. The Sun is at one focus. The planet follows the ellipse in its orbit, meaning that the planet to Sun distance is constantly changing as the planet goes around its orbit.
The solar system—facts and information
Known as natural satellites, they orbit planets, dwarf planets, asteroids, and other debris. Among the planets, moons are more common in the outer reaches of the solar system. Mercury and Venus ...
Kepler's laws of planetary motion
The squares of the sidereal periods (P) of the planets are directly proportional to the cubes of their mean distances (d) from the Sun. Kepler's three laws of planetary motion can be stated as follows: ( 1) All planets move about the Sun in elliptical orbits, having the Sun as one of the foci. ( 2) A radius vector joining any planet to the ...
NASA SVS
The eight planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Mercury is closest to the Sun. Neptune is the farthest. Planets, asteroids, and comets orbit our Sun. They travel around our Sun in a flattened circle called an ellipse. It takes the Earth one year to go around the Sun. Mercury goes around the Sun in only ...
3.2: The Laws of Planetary Motion
In 1619, Kepler discovered a basic relationship to relate the planets' orbits to their relative distances from the Sun. We define a planet's orbital period, (P), as the time it takes a planet to travel once around the Sun. Also, recall that a planet's semimajor axis, a, is equal to its average
Planets of our Solar System
At the centre is the Sun. Orbiting around the Sun are eight planets with over 100 moons between them, at least five dwarf planets, countless asteroids and the occasional comet. In this Space guide ...
Do all planets orbit in a flat plane around their suns?
Here's the yes part of the answer, beginning with another astronomy definition; the Earth-sun plane is called the ecliptic. Most major planets in our solar system stay within 3 degrees of the ...
Sun
Other parts of the molecular cloud cooled into a disc around the brand-new sun and became planets, asteroids, comets, and other bodies in our solar system. ... An AU can be measured at light speed, or the time it takes for a photon of light to travel from the sun to Earth. It takes light about eight minutes and 19 seconds to reach Earth from ...
Orbit of the Planets in the Solar System
Looking into the different orbits of the planets in the Solar System. #space #science #solarsystem https://www.inspire.education
Sun: Facts
The Sun would have been surrounded by a disk of gas and dust early in its history when the solar system was first forming, about 4.6 billion years ago. Some of that dust is still around today, in several dust rings that circle the Sun. They trace the orbits of planets, whose gravity tugs dust into place around the Sun.
7.1 Kepler's Laws of Planetary Motion
The orbit of each planet around the sun is an ellipse with the sun at one focus. Each planet moves so that an imaginary line drawn from the sun to the planet sweeps out equal areas in equal times. The ratio of the squares of the periods of any two planets about the sun is equal to the ratio of the cubes of their average distances from the sun.
Why Do Planets Orbit The Sun? (Explained!)
The Earth and other planets in the solar system orbit around the Sun; this orbit relies on a set of physical forces that continuously fight against the laws of motion. A planet's momentum makes them want to continue its path of travel in a straight line, but the gravity of the Sun prevents this and pulls the orbiting body closer.
How many times has Earth orbited the sun?
Mercury, the closest planet to the sun, takes only 88 days (or roughly 0.24 years, based on a year with 365.25 days) to travel around the sun once. So, over the past 4.5 billion years, it has ...
PDF Destination L1: A Thematic Unit Kepler's Laws of Planetary Motion
The science activities in this module deal with the concept of travel as it relates to natural objects (planets) traveling around the sun. The activities are designed to let the students discover Kepler's Laws of Planetary Motion by completing assignments about the laws. In the first activity, "Round and Round," students are given some ...
3.1 The Laws of Planetary Motion
In 1619, Kepler discovered a basic relationship to relate the planets' orbits to their relative distances from the Sun. We define a planet's orbital period, (P), as the time it takes a planet to travel once around the Sun. Also, recall that a planet's semimajor axis, a, is equal to its average
Sun
The Sun's gravity holds the solar system together, keeping everything - from the biggest planets to the smallest particles of debris - in its orbit. The connection and interactions between the Sun and Earth drive the seasons, ocean currents, weather, climate, radiation belts and auroras. Though it is special to us, there are billions of ...
How Long is a Year on Other Planets?
If a planet is close to the Sun, the distance it orbits around the Sun is fairly short. This distance is called an orbital path. The closer a planet travels to the Sun, the more the Sun's gravity can pull on the planet. The stronger the pull of the Sun's gravity, the faster the planet orbits. Check out how long a year is on each planet below!
ESA
Moons and rings. All of the planets travel around the Sun in a counter-clockwise direction - as seen from above Earth's north pole. Their year - the time they take to complete one orbit - varies with their distance from the Sun. A year on Mercury lasts for just 88 Earth days, so someone born there would have four times as many birthdays as ...
Orbital Speed of Planets in Order
Below is a list of the planet's orbital speeds in order from fastest to slowest. 1. Mercury is the fastest planet, which speeds around the sun at 47.87 km/s. In miles per hour this equates to a whopping 107,082 miles per hour. 2. Venus is the second fastest planet with an orbital speed of 35.02 km/s, or 78,337 miles per hour. 3.
Planet Where It's Sunny Every Day Spotted 280 Light-Years Away
This distant exoplanet, named WASP-43 b, is a hot gas giant orbiting a star around 280 light years away from our solar system, and dramatic weather patterns have been detected, including winds of ...
Jupiter: Facts
From this distance, it takes sunlight 43 minutes to travel from the Sun to Jupiter. Orbit and Rotation. Jupiter has the shortest day in the solar system. One day on Jupiter takes only about 10 hours (the time it takes for Jupiter to rotate or spin around once), and Jupiter makes a complete orbit around the Sun (a year in Jovian time) in about ...

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3.1 The Laws of Planetary Motion

Tycho Brahe’s Observatory

Johannes Kepler

The First Two Laws of Planetary Motion

Link to Learning

Kepler’s Third Law

Example 3.1

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How Long is a Year on Other Planets?

Why does NASA care about years on other planets?

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