Jupiter - Educational facts and history of the planet Jupiter. Jupiter News Jupiter Facts Jupiter is the fifth planet from the Sun and by far the largest. Jupiter is more than twice as massive as all the other planets combined (the mass of Jupiter is 318 times that of Earth). Planet Profile orbit : 778,330,000 km (5.20 AU ) from Sun diameter : 142,984 km (equatorial) mass : 1.900e27 kg History of Jupiter Jupiter (a.k.a. Jove; Greek Zeus ) was the King of the Gods, the ruler of Olympus and the patron of the Roman state. Zeus was the son of Cronus (Saturn). Jupiter is the fourth brightest object in the sky (after the Sun , the Moon and Venus ). It has been known since prehistoric times as a bright "wandering star". But in 1610 when Galileo first pointed a telescope at the sky he discovered Jupiter's four large moons Io , Europa , Ganymede and Callisto (now known as the Galilean moons) and recorded their motions back and forth around Jupiter.

This was the first discovery of a center of motion not apparently centered on the Earth. It was a major point in favor of Copernicus 's heliocentric theory of the motions of the planets (along with other new evidence from his telescope: the phases of Venus and the mountains on the Moon ). Galileo's outspoken support of the Copernican theory got him in trouble with the Inquisition . Today anyone can repeat Galileo's observations (without fear of retribution :-) using binoculars or an inexpensive telescope. Jupiter was first visited by Pioneer 10 in 1973 and later by Pioneer 11 , Voyager 1 , Voyager 2 and Ulysses . The spacecraft Galileo orbited Jupiter for eight years. It is still regularly observed by the Hubble Space Telescope . The gas planets do not have solid surfaces, their gaseous material simply gets denser with depth (the radii and diameters quoted for the planets are for levels corresponding to a pressure of 1 atmosphere). What we see when looking at these planets is the tops of clouds high in their atmospheres (slightly above the 1 atmosphere level).

Jupiter is about 90% hydrogen and 10% helium (by numbers of atoms, 75/25% by mass) with traces of methane, water, ammonia and "rock". This is very close to the composition of the primordial Solar Nebula from which the entire solar system was formed. Saturn has a similar composition, but Uranus and Neptune have much less hydrogen and helium. Our knowledge of the interior of Jupiter (and the other gas planets) is highly indirect and likely to remain so for some time. (The data from Galileo 's atmospheric probe goes down only about 150 km below the cloud tops.) Jupiter probably has a core of rocky material amounting to something like 10 to 15 Earth-masses. Above the core lies the main bulk of the planet in the form of liquid metallic hydrogen. This exotic form of the most common of elements is possible only at pressures exceeding 4 million bars , as is the case in the interior of Jupiter (and Saturn). Liquid metallic hydrogen consists of ionized protons and electrons (like the interior of the Sun but at a far lower temperature). At the temperature and pressure of Jupiter's interior hydrogen is a liquid, not a gas.

It is an electrical conductor and the source of Jupiter's magnetic field. This layer probably also contains some helium and traces of various " ices ". The outermost layer is composed primarily of ordinary molecular hydrogen and helium which is liquid in the interior and gaseous further out. The atmosphere we see is just the very top of this deep layer. Water, carbon dioxide, methane and other simple molecules are also present in tiny amounts. Recent experiments have shown that hydrogen does not change phase suddenly. Therefore the interiors of the jovian planets probably have indistinct boundaries between their various interior layers. Three distinct layers of clouds are believed to exist consisting of ammonia ice, ammonium hydrosulfide and a mixture of ice and water. However, the preliminary results from the Galileo probe show only faint indications of clouds (one instrument seems to have detected the topmost layer while another may have seen the second). But the probe's entry point (left) was unusual -- Earth-based telescopic observations and more recent observations by the Galileo orbiter suggest that the probe entry site may well have been one of the warmest and least cloudy areas on Jupiter at that time. Data from the Galileo atmospheric probe also indicate that there is much less water than expected.

The expectation was that Jupiter's atmosphere would contain about twice the amount of oxygen (combined with the abundant hydrogen to make water) as the Sun. But it now appears that the actual concentration much less than the Sun's. Also surprising was the high temperature and density of the uppermost parts of the atmosphere. Jupiter and the other gas planets have high velocity winds which are confined in wide bands of latitude. The winds blow in opposite directions in adjacent bands. Slight chemical and temperature differences between these bands are responsible for the colored bands that dominate the planet's appearance. The light colored bands are called zones; the dark ones belts. The bands have been known for some time on Jupiter, but the complex vortices in the boundary regions between the bands were first seen by Voyager. The data from the Galileo probe indicate that the winds are even faster than expected (more than 400 mph) and extend down into as far as the probe was able to observe; they may extend down thousands of kilometers into the interior. Jupiter's atmosphere was also found to be quite turbulent. This indicates that Jupiter's winds are driven in large part by its internal heat rather than from solar input as on Earth.

The vivid colors seen in Jupiter's clouds are probably the result of subtle chemical reactions of the trace elements in Jupiter's atmosphere, perhaps involving sulfur whose compounds take on a wide variety of colors, but the details are unknown. The colors correlate with the cloud's altitude: blue lowest, followed by browns and whites, with reds highest. Sometimes we see the lower layers through holes in the upper ones. The Great Red Spot (GRS) has been seen by Earthly observers for more than 300 years (its discovery is usually attributed to Cassini , or Robert Hooke in the 17th century). The GRS is an oval about 12,000 by 25,000 km, big enough to hold two Earths. Other smaller but similar spots have been known for decades. Infrared observations and the direction of its rotation indicate that the GRS is a high-pressure region whose cloud tops are significantly higher and colder than the surrounding regions. Similar structures have been seen on Saturn and Neptune . It is not known how such structures can persist for so long. Jupiter radiates more energy into space than it receives from the Sun.

The interior of Jupiter is hot: the core is probably about 20,000 K. The heat is generated by the Kelvin-Helmholtz mechanism, the slow gravitational compression of the planet. (Jupiter does NOT produce energy by nuclear fusion as in the Sun; it is much too small and hence its interior is too cool to ignite nuclear reactions.) This interior heat probably causes convection deep within Jupiter's liquid layers and is probably responsible for the complex motions we see in the cloud tops. Saturn and Neptune are similar to Jupiter in this respect, but oddly, Uranus is not. Jupiter is just about as large in diameter as a gas planet can be. If more material were to be added, it would be compressed by gravity such that the overall radius would increase only slightly. A star can be larger only because of its internal (nuclear) heat source. (But Jupiter would have to be at least 80 times more massive to become a star.) Jupiter has a huge magnetic field, much stronger than Earth's. Its magnetosphere extends more than 650 million km (past the orbit of Saturn!).

(Note that Jupiter's magnetosphere is far from spherical -- it extends "only" a few million kilometers in the direction toward the Sun.) Jupiter's moons therefore lie within its magnetosphere, a fact which may partially explain some of the activity on Io . Unfortunately for future space travelers and of real concern to the designers of the Voyager and Galileo spacecraft, the environment near Jupiter contains high levels of energetic particles trapped by Jupiter's magnetic field. This "radiation" is similar to, but much more intense than, that found within Earth's Van Allen belts. It would be immediately fatal to an unprotected human being. The Galileo atmospheric probe discovered a new intense radiation belt between Jupiter's ring and the uppermost atmospheric layers. This new belt is approximately 10 times as strong as Earth's Van Allen radiation belts. Surprisingly, this new belt was also found to contain high energy helium ions of unknown origin. J upiter has rings like Saturn's, but much fainter and smaller (right). They were totally unexpected and were only discovered when two of the Voyager 1 scientists insisted that after traveling 1 billion km it was at least worth a quick look to see if any rings might be present.

Everyone else thought that the chance of finding anything was nil, but there they were. It was a major coup. They have since been imaged in the infra-red from ground-based observatories and by Galileo . Unlike Saturn's, Jupiter's rings are dark ( albedo about .05). They're probably composed of very small grains of rocky material. Unlike Saturn's rings, they seem to contain no ice. Particles in Jupiter's rings probably don't stay there for long (due to atmospheric and magnetic drag). The Galileo spacecraft found clear evidence that the rings are continuously resupplied by dust formed by micrometeor impacts on the four inner moons , which are very energetic because of Jupiter's large gravitational field. The inner halo ring is broadened by interactions with Jupiter's magnetic field. In July 1994, Comet Shoemaker-Levy 9 collided with Jupiter with spectacular results (left). The effects were clearly visible even with amateur telescopes. The debris from the collision was visible for nearly a year afterward with HST. When it is in the nighttime sky, Jupiter is often the brightest "star" in the sky (it is second only to Venus, which is seldom visible in a dark sky).

The four Galilean moons are easily visible with binoculars; a few bands and the Great Red Spot can be seen with a small astronomical telescope. There are several Web sites that show the current position of Jupiter (and the other planets) in the sky. More detailed and customized charts can be created with a planetarium program . Jupiter's Satellites Jupiter has 67 known satellites : the four large Galilean moons plus many more small ones some of which have not yet been named: Jupiter is very gradually slowing down due to the tidal drag produced by the Galilean satellites. Also, the same tidal forces are changing the orbits of the moons, very slowly forcing them farther from Jupiter. Io, Europa and Ganymede are locked together in a 1:2:4 orbital resonance and their orbits evolve together. Callisto is almost part of this as well. In a few hundred million years, Callisto will be locked in too, orbiting at exactly twice the period of Ganymede (eight times the period of Io). Jupiter's satellites are named for other figures in the life of Zeus (mostly his numerous lovers). Many more small moons have been discovered recently but have not as yet been officially confirmed or named.

The most up to date info on them can be found at Scott Sheppard's site .

Distance Radius Mass Satellite (000 km) (km) (kg) Discoverer Date --------- -------- ------ ------- ---------- ----- Metis 128 20 9.56e16 Synnott 1979 Adrastea 129 10 1.91e16 Jewitt 1979 Amalthea 181 98 7.17e18 Barnard 1892 Thebe 222 50 7.77e17 Synnott 1979 Io 422 1815 8.94e22 Galileo 1610 Europa 671 1569 4.80e22 Galileo 1610 Ganymede 1070 2631 1.48e23 Galileo 1610 Callisto 1883 2400 1.08e23 Galileo 1610 Leda 11094 8 5.68e15 Kowal 19

74 Himalia 11480 93 9.56e18 Perrine 1904 Lysithea 11720 18 7.77e16 Nicholson 1938 Elara 11737 38 7.77e17 Perrine 1905 Ananke 21200 15 3.82e16 Nicholson 1951 Carme 22600 20 9.56e16 Nicholson 1938 Pasiphae 23500 25 1.91e17 Melotte 1908 Sinope 23700 18 7.77e16 Nicholson 1914 Values for the smaller moons are approximate.

Many more small moons are not listed here. Distance Width Mass Ring (km) (km) (kg) ---- -------- ----- ------ Halo 100000 22800 ? Main 122800 6400 1e13 Gossamer 129200 214200 ? (distance is from Jupiter's center to the ring's inner edge) More about Jupiter and its satellites The asteroid belt lies between the orbits of which two planets? A. Earth and Mars B. Mars and Jupiter C. Jupiter and Saturn D. Saturn and Uranus You have new items in your feed. Click to view. Question and answer The asteroid belt lies between the orbits of which two planets? A. Earth and Mars B. Mars and Jupiter C. Jupiter and Saturn D. Saturn and Uranus This question has not been answered. Can you answer it? Please add your answer below ... Get an answer The asteroid belt lies between the orbits of which two planets? A. Earth and Mars B. Mars and Jupiter C. Jupiter and Saturn D. Saturn and Uranus Original conversation User: The asteroid belt lies between the orbits of which two planets?

A. Earth and Mars B. Mars and Jupiter C. Jupiter and Saturn D. Saturn and Uranus User: Even though our solar system sits on one spiral arm of the Milky Way, we know the shape of the Milky Way due to a combination of telescopic imaging and A. deductive reasoning. B. interstellar exploration. C. inferential extrapolation. D. supercomputer calculations. What are the planets in order from the sun? | Reference.com What are the planets in order from the sun? A: Quick Answer The order of the planets from the sun is Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Before 2006, Pluto was considered to be a planet; as of 2014, it is considered to be a dwarf planet. Full Answer Mercury, Venus, Earth and Mars are called the inner planets. These planets are smaller than the other planets and mostly made of rock. Jupiter, Saturn, Uranus and Neptune are the outer planets. They are large balls of gases. An asteroid belt lies between Mars and Jupiter. A planet is a large object in space that orbits a star and reflects light from that star.

As of 2014, scientists have found eight planets in this solar system. Each planet has its own unique orbit. Besides Earth, all planets are named for an ancient Roman deity. Another class of objects known as dwarf planets was created in 2006. Scientists created this category after discovering new objects in a distant region of the solar system, known as the Kuiper Belt, which were of similar size or larger than Pluto. Dwarf planets must orbit the sun and have enough mass have become round due to their own gravity. Planets have cleared their orbits around the sun so no other similar objects are at the same distance. Dwarf planets fail to do this. Planet Jupiter: Facts About Its Size, Moons and Red Spot Planet Jupiter: Facts About Its Size, Moons and Red Spot By Charles Q. Choi, Space.com Contributor | November 14, 2014 12:59am ET MORE This photo of Jupiter was taken on Sept. 20, 2010 when Jupiter made its closest approach to Earth since 1963. (Uranus [insert] was visible through telescopes near Jupiter.) Credit: Jimmy Eubanks Jupiter is the largest planet in the solar system.

Fittingly, it was named after the king of the gods in Roman mythology. In a similar manner, the ancient Greeks named the planet after Zeus, the king of the Greek pantheon. Jupiter helped revolutionize the way we saw the universe and ourselves in 1610, when Galileo discovered Jupiter's four large moons — Io, Europa, Ganymede and Callisto, now known as the Galilean moons. This was the first time celestial bodies were seen circling an object other than Earth, major support of the Copernican view that Earth was not the center of the universe. Physical characteristics Jupiter is the most massive planet in our solar system , more than twice as massive as all the other planets combined, and had it been about 80 times more massive, it would have actually become a star instead of a planet. Its atmosphere resembles that of the sun, made up mostly of hydrogen and helium, and with four large moons and many smaller moons in orbit around it, Jupiter by itself forms a kind of miniature solar system. All told, the immense volume of Jupiter could hold more than 1,300 Earths.

The colorful bands of Jupiter are arranged in dark belts and light zones created by strong east-west winds in the planet's upper atmosphere traveling more than 400 mph (640 kph). The white clouds in the zones are made of crystals of frozen ammonia, while darker clouds of other chemicals are found in the belts. At the deepest visible levels are blue clouds. Far from being static, the stripes of clouds change over time . Inside the atmosphere, diamond rain may fill the skies. The most extraordinary feature on Jupiter is undoubtedly the Great Red Spot , a giant hurricane-like storm seen for more than 300 years. At its widest, the Great Red Spot is three times the diameter of the Earth, and its edge spins counterclockwise around its center at a speed of about 225 mph (360 kph). The color of the storm, which usually varies from brick red to slightly brown, may come from small amounts of sulfur and phosphorus in the ammonia crystals in Jupiter's clouds. The spot grows and shrinks over time, and every now and again, seems to fade entirely.

Jupiter's gargantuan magnetic field is the strongest of all the planets in the solar system at nearly 20,000 times the strength of Earth's. It traps electrically charged particles in an intense belt of electrons and other electrically charged particles that regularly blasts the planet's moons and rings with a level of radiation more than 1,000 times the lethal level for a human, damaging even heavily shielded spacecraft such as NASA's Galileo probe. The magnetosphere of Jupiter, which is composed of these fields and particles, swells out some 600,000 to 2 million miles (1 million to 3 million km) toward the sun and tapers to a tail extending more than 600 million miles (1 billion km) behind Jupiter. Jupiter spins faster than any other planet, taking a little under 10 hours to complete a turn on its axis, compared with 24 hours for Earth. This rapid spin makes Jupiter bulge at the equator and flatten at the poles, making the planet about 7 percent wider at the equator than at the poles. Jupiter broadcasts radio waves strong enough to detect on Earth.

These come in two forms — strong bursts that occur when Io, the closest of Jupiter's large moons, passes through certain regions of Jupiter's magnetic field, and continuous radiation from Jupiter's surface and high-energy particles in its radiation belts. These radio waves could help scientists to probe the oceans on its moons. Composition & structure Atmospheric composition (by volume): 89.8 percent molecular hydrogen, 10.2 percent helium, minor amounts of methane, ammonia, hydrogen deuteride, ethane, water, ammonia ice aerosols, water ice aerosols, ammonia hydrosulfide aerosols Magnetic field: Nearly 20,000 times stronger than Earth's Chemical composition: Jupiter has a dense core of uncertain composition , surrounded by a helium-rich layer of fluid metallic hydrogen, wrapped up in an atmosphere primarily made of molecular hydrogen. Internal structure: A core less than 10 times Earth's mass surrounded by a layer of fluid metallic hydrogen extending out to 80 to 90 percent of the diameter of the planet, enclosed in an atmosphere mostly made of gaseous and liquid hydrogen.

Orbit & rotation Average distance from the sun : 483,682,810 miles (778,412,020 km). By comparison: 5.203 times that of Earth Perihelion (closest approach to the sun): 460,276,100 miles (740,742,600 km). By comparison: 5.036 times that of Earth Aphelion (farthest distance from the sun): 507,089,500 miles (816,081,400 km). By comparison: 5.366 times that of Earth (Source: NASA .) Jupiter's moons Jupiter has at least 63 moons , which are often named after the Roman god's many lovers. The four largest moons of Jupiter, now called Io, Europa, Ganymede, and Callisto, were discovered by Galileo Galilei himself, and are appropriately known today as the Galilean satellites. Ganymede is the largest moon in our solar system, larger even than Mercury and Pluto.

It is also the only moon known to have its own magnetic field. The moon has at least one thick ocean between layers of ice, although it may contain several layers of both materials. Io is the most volcanically active body in our solar system. The sulfur its volcanoes spew out gives Io a blotted yellow-orange appearance that is often compared to a pepperoni pizza. As Io orbits Jupiter, the planet's immense gravity causes 'tides' in Io's solid surface that rise 300 feet (100 meters) high, generating enough heat for volcanic activity. The frozen crust of Europa is made up mostly of water ice, and it may hide a liquid ocean holding twice as much water as Earth does. Icy oceans may also exist beneath the crusts of Callisto and Ganymede. Some of this liquid spouts from the surface in newly spotted sporadic plumes at the southern pole. Its potential to host life caused NASA to request funding for a mission to explore Europa . Callisto has the lowest reflectivity, or albedo, of the four Galilean moons. This suggests that its surface may be composed of dark, colorless rock.

Jupiter's rings Jupiter's three rings came as a surprise when NASA's Voyager 1 spacecraft discovered them around the planet's equator in 1979. Each are much fainter than Saturn's rings. The main ring is flattened. It is about 20 miles (30 km) thick and more than 4,000 miles (6,400 km) wide. The inner cloud-like ring, called the halo, is roughly 12,000 miles (20,000 km) thick. The halo extends halfway from the main ring down to the planet's cloud tops and expands by interaction with Jupiter's magnetic field. Both the main ring and halo are composed of small, dark particles. The third ring, known as the gossamer ring because of its transparency, is actually three rings of microscopic debris from three of Jupiter's moons, Amalthea, Thebe and Adrastea.

It is probably made up of dust particles less than 10 microns in diameter, about the same size of the particles found in cigarette smoke, and extends to an outer edge of about 80,000 miles (129,000 km) from the center of the planet and inward to about 18,600 miles (30,000 km). Ripples in the rings of both Jupiter and Saturn may be signs of impacts from comets and asteroids. Research & exploration Seven missions have flown by Jupiter — Pioneer 10 , Pioneer 11 , Voyager 1 , Voyager 2 , Ulysses, Cassini and New Horizons — while another, NASA's Galileo, actually orbited the planet. Pioneer 10 revealed how dangerous Jupiter's radiation belt is, while Pioneer 11 provided data on the Great Red Spot and close-up pictures of its polar region. Voyager 1 and 2 helped astronomers create the first detailed maps of the Galilean satellites, discovered Jupiter's rings, revealed sulfur volcanoes on Io, and saw lightning in Jupiter's clouds.

Ulysses discovered the solar wind has a much greater impact on Jupiter's magnetosphere than before suggested. New Horizons took close-up pictures of Jupiter and its largest moons. In 1995, Galileo sent a probe plunging towards Jupiter, making the first direct measurements of its atmosphere and measuring the amount of water and other chemicals there. When Galileo ran low on fuel, the craft was intentionally crashed into Jupiter's atmosphere to avoid any risk of it slamming into and contaminating Europa, which might have an ocean below its surface capable of supporting life. Another spacecraft, named Juno , is heading toward Jupiter and will reach the planet in 2016. It will study Jupiter from a polar orbit to figure out how it and the rest of the solar system formed, which could shed light on how alien planetary systems might have developed. Jupiter's gravitational impact on the solar system As the most massive body in the solar system after the sun, the pull of Jupiter's gravity has helped shape the fate of our system. It may have violently hurled Neptune and Uranus outward , according to calculations published in the journal Nature.

Jupiter, along with Saturn, may have slung a barrage of debris toward the inner planets early in the system's history, according to an article in Science magazine. It may even nowadays help keep asteroids from bombarding Earth, and recent events certainly have shown that it can absorb potentially deadly impacts . Currently, Jupiter's gravitational field influences numerous asteroids that have clustered into the regions preceding and following Jupiter in its orbit around the sun. These are known as the Trojan asteroids, after three large asteroids there, Agamemnon, Achilles and Hector, names drawn from the Iliad, Homer's epic about the Trojan War. Possibility of life on Jupiter If one were to dive into Jupiter's atmosphere , one would discover it to grow warmer with depth, reaching room temperature, or 70 degrees F (21 degrees C), at an altitude where the atmospheric pressure is about 10 times as great as it is on Earth. Scientists have conjectured that if Jupiter has any form of life, it might dwell at this level, and would have to be airborne. However, researchers have found no evidence for life on Jupiter.

Additional reporting by Nola Taylor Redd, Space.com Contributor Explore the solar system The "Jovian" Planets: Jupiter, Saturn, Uranus, and Neptune During the last class we discussed the terrestrial planets--that is those planets that are most like the Earth in size, composition, and structure. While the geologies of the inner four planets have some things in common, we have found that each one is quite different from the others. The next four planets we will talk about--Jupiter, Saturn, Uranus, and Neptune--are very different to the terrestrial planets in that they have no real solid surfaces, being dominated by thick, deep atmospheres. Thus, there is no "geology" to speak of, and we talk more about the meteorology (weather) of these gas giants. Jupiter Jupiter is the fifth planet from the Sun, and is the largest planet in the solar system. Its average distance from the Sun is 5.2 AU (778,330,000 km), and its equatorial radius is 68,700 km (almost 11 times that of Earth).

Though Jupiter is very massive (having 318 times the mass of the Earth), it is not very dense: it has a mean density of 1.4 gm/cm3. Just slightly more dense than water! Suprisingly, even though Jupiter is enormous, it spins very rapidly, completing one rotation in slightly under 10 hours. It takes 12 years for Jupiter to circle the Sun. Jupiter is a swirling ball of clouds arranged in rotating storms and in complex bands: These bands are caused by rising and descending air, as shown in Fig. 12.8 of the textbook: Jupiter is mostly a large ball of hydrogen and helium gas with a few trace elements: This picture illustrates the internal structure of Jupiter. The outer layer is primarily composed of molecular hydrogen. At greater depths the hydrogen starts resembling a liquid. At 10,000 kilometers below Jupiter's cloud top liquid hydrogen reaches a pressure of 1,000,000 bar with a temperature of 6,000ï¿½ K. At this state hydrogen changes into a phase of liquid metallic hydrogen. In this state, the hydrogen atoms break down yielding ionized protons and electrons similar to the Sun's interior.

Below this is a layer dominated by ice where "ice" denotes a soupy liquid mixture of water, methane, and ammonia under high temperatures and pressures. Finally at the center is a rocky or rocky-ice core of up to 10 Earth masses.1 The rapid rotation of Jupiter creates an incredible amount of shear in the atmosphere, and all kinds of storms form. The biggest of these, the "great red spot" was discovered by Cassini in the 17th century: The red spot is simply a high pressure area like those seen on the Earth: Jupiter has no real solid surface, with the clouds gradually compressing to a liquid state, and this further compresses into a "metallic" state that surrounds the rocky core. The temperature of Jupiter at the cloud tops is very cold, -121 C, but increases dramatically as you go inwards, reaching to 20,000 K in the core. Jupiter has a large number of known moons (about 63 of them), but most of these are tiny little rocks (< 5 km in radii).

There are four major moons of Jupiter: the "Galilean satellites" Io , Europa , Ganymede , and Callisto (shown in order, below--that tiny oblong rock to the left of Io is one of the smaller moons Almathea, that orbits inside that of Io). The innermost of these four moons is Io, and its surface is covered with lava flows from the numerous volcanoes on its surface (go to pages 347 and 348 of the textbook for more images). In fact, Io has the youngest surface in the solar system, being constantly reshaped by volcanic eruptions. The yellowish-orange color of Io is due to the large amount of sulfur that is discharged in these eruptions. Here is a possible lake of sulfur: The reason Io has so many volcanoes is that the intense gravity of Jupiter, and that of the other three moons, constantly tugs on Io, stretching and compressing it (see page 349 of the textbook): This generates an enormous amount of heat that liquifies the insides of Io. This process is also at work on the next moon out from Jupiter, Europa. Europa has one of the smoothest and brightest surfaces in the solar system.

It is believed to be frozen water ice. Because ice is plastic (it flows), features with large elevations (mountains, craters, etc.) are not sustainable, and thus the surface is relatively smooth, but is covered with a large number of cracks: It is now believed that Europa has a large ocean of water beneath its frozen crust. This is also probably the case for the largest moon of Jupiter, Ganymede. Here are cutaway drawings of the internal structures of Jupiter's four moons (blue signifies water): Here is a close-up of two possible models for Europa: Plans are being drawn-up to explore Europa and/or Ganymede as they may be ideal sites for life to have evolved and to currently exist. For more on Europa, go here . The largest planetary satellite in the solar system is Ganymede (radius of 2,600 km).

It is mostly rock and ice, here are two close-ups: The final Gallilean satellite is Callisto, with a radius of 2400 km, it has one of the most battered surfaces of any object in the solar system: Saturn Saturn is the second largest planet in the solar system, with a radius of 60,268 km (9.45 times Earth), and orbits at an average distance of 9.54 AU (1,429,400,000 km) from the Sun, taking 29 years to complete one orbit. While Saturn is massive, equivalent to 95 Earth's, it has the lowest density of all of the planets: 0.71 gm/cm3, less than that of water! If Saturn was a solid object, and you had a big enough ocean, it would float. Saturn is certainly the most photogenic of all of the planets: It also has storms and features like those seen on Jupiter: The ring system of Saturn is composed of many small boulders, rocks and dust from a disrupted moon. The rings themselves are about 250,000 km in diameter, but less than 1 km thick!

The rings of Saturn are actually divided into innumerable smaller rings, as these close-ups show: The reason for the division is that the small particles that orbit Saturn are tugged-on by the various moons of Saturn, and this creates orbital resonances, sweeping the region clear (see pages 359 and 360 of the textbook). Like Jupiter, Saturn is a big ball of hydrogen and helium gas. At the very center, there may be a small rocky core. Outside of this core, however, is probably a weird high-pressure rock/ice mixture: Saturn has 34 named moons, though the total is now up to 62! Most of them are small, but Saturn boasts the second largest (after Ganymede) moon in the solar system: Titan. Titan has a thick atmosphere that obscures the surface from view: Titan is larger than Mercury (2,575 km in radius vs. 2,432 km), but much less massive since it only has a density of 2.2 gm/cm3. Titan's atmosphere seems to be mostly methane. At one time, many people thought that Titan might be a possible site for life.

But recent discoveries have shown that the surface temperature is very low (-289oF), lower than previously expected (there was hope of an intense greenhouse effect). Recent near-infrared observations from the ground show surface features on Titan (and a bright white cloud): In January of 2005 the Huygens probe (of the Cassini mission) dropped into the atmosphere of Titan and parachuted down to the surface taking pictures and analyzing the composition of the atmosphere. Huygens images: A sinuous river-like feature on Titan (probably a methane = liquid natural gas river!). A cliff, or plateau region on Titan, with drainage features into a smoother region (a methane lake?). Note the lack of craters in these two images---Titan's surface is young. Blocks of (water?) ice on the surface of Titan. Here is an image of one of the smaller moons of Saturn called Hyperion: Water plumes/geysers on Enceladus: Uranus and Neptune Uranus has a radius of 25,500 km, and a mass of 14.5 Earth's. It has a density similar to Jupiter: 1.32 gm/cm3.

It also spins rapidly, and has a "day" of 10 hours and 49 minutes. It orbits the Sun at an average distance of 19.2 AU (2.8 billion km), and takes 84 years to complete one trip around the Sun. Uranus is very strange in that its rotational axis lies very close to its orbital plane. This means that the seasons on Uranus are very long, with 21 years that have near constant daylight ("summer"), and 21 years of almost perpetual darkness ("winter"). The disk of Uranus is almost completely featureless. There appears to be a high-altitude haze that blocks our view of the cloud deck. Saturn also has this haze layer, but it is not as thick as that of Uranus (Jupiter doesn't really have this structure). The cloud tops of Uranus are very cold, -200 C!

Uranus has a structure similar to Jupiter and Saturn, a big ball of hydrogen and helium gas with a rocky core about equal to one Earth in size: Like Saturn, Uranus has a ring system, but here the rings have much less material in them, and they are not quite as spectacular: Uranus now has 21 named moons (and six unnamed moons), several of them quite interesting in their own rite, but none of them are very large (the largest, Oberon, has a radius of 761 km, for a comparison of the satellite systems of the Jovian planets, see the Figure 12.16 in the textbook also shown here:). Neptune is much further from the Sun than Uranus (30 AU), and takes 165 years to complete one orbit. Neptune has 17.2 Earth masses, so it is more massive than Uranus. Note, however, that it is smaller in size than Uranus, having a radius of 24,700 km. Thus, it must have a higher density: 1.63 gm/cm3.

Neptune also is the slowest rotating of the Jovian planets, with a rotation period of 16 hours. Strangely, Neptune's atmosphere appears to be much more active than that of Uranus (maybe the haze layer "freezes out" at this distance, where the cloud-top temperature is colder than that of Uranus), and has several large storms similar to those on Jupiter: Neptune also has a very tenuous ring system like the other gas giants. Neptune has one very large moon (of the thirteen known) named Triton , that is 2,700 km in diameter: Triton has a tenuous atmosphere that is mostly composed of nitrogen. A surprising discovery were these black plumes seen in the photo below that appear to be liquid nitrogen geysers. The plumes seem to be blowing in a wind from the point of origin: Overview of the Solar System We compare the properties of the planets to learn how the solar system formed and why the earth is such a special place.

Key points: Terrestrial and giant planets; range of properties with distance from sun and what drives them; retention of gas and atmospheres Overview of the Solar System The Planets to Scale; from the sun, the "terrestrial planets" are Mercury, Venus, Earth, and Mars, while the "giant planets" are Jupiter, Saturn, Uranus, and Neptune (Pluto was an oddity at the end*). (from ) *On August 24, 2006, the International Astronomical Union - the body that oversees such matters - voted to strip Pluto of its planet status. By official decree, we now have only eight planets. Terrestrial Planet Properties From Mercury to Mars, their distances from the sun range from about 0.4 to 1.5 times the distance of the earth from the sun, defined as an astronomical unit (AU) Mercury, Venus, Earth, Mars all have average densities greater than 3 grams/cm3 All four have rocky surfaces and rocky/metallic interiors Atmospheres vary greatly (e.g.

none for Mercury to very dense for Venus) but heavier molecules like CO2 tend to dominate over lighter ones such as H2 Only the Earth has an appreciable magnetic field (Venus and Mercury rotate too slowly, Mars apparently no longer has a liquid core) Here is a rough comparison of their interior structures. They are all variations on a common theme, with solid iron cores inside liquid iron components (except for Mars, where the interior temperature is too low to liquify this zone), surrounded by mantles of silicate rock, overlaid with rocky crusts. (from Nick Strobel's Astronomy Notes . Go to his site at for the updated and corrected version.) Distances from the sun range from about 5 AU (Jupiter) to 30 AU (Neptune) Average densities are low, similar to water: Jupiter is 1.3 grams/cm3 and Saturn is 0.7 grams/cm3 Composition similar to Sun -- (especially Jupiter and Saturn) 80% hydrogen The average speed of an atom or molecule goes as the square root of the temperature divided by the mass of the particle. If the speeds are close to the escape velocity, gases will leak away into space.

At the high temperatures at the orbit of Mercury (and its relatively small gravity), all gaseous materials escaped. For Venus and Earth, the lower temperature and larger gravity allowed heavier gases to be retained (oxygen, nitrogen) but hydrogen and helium escaped. Mars lost most of its gases because its surface gravity is small. The giant planets were out where temperatures were low enough to retain virtually all the gases. The ice line for the Solar System lies between Mars and Jupiter. It marks a major divide in planet properties because outside of it, various kinds of frozen light molecules could accumulate on a forming planet as ices (for example, frozen water captures not only oxygen, but some hydrogen). These ices ran up the mass of the planet so it had a chance to retain the light gases, even helium and hydrogen. Thus, the giant planets (around the sun AND the other stars) probably all had to form outside of the frost line. Test your understanding before going on Formation of the sun and moon, ceiling painting, St. Isaac's Cathedral, St. Petersburg (photo by G.

Rieke) Uranus Facts: Interesting Facts about Planet Uranus • The Planets Interactive Solar System Model Uranus Facts Uranus, named after the the father of the Roman god Saturn, is the seventh planet in the Solar System and third of the gas giants . It is the third largest planet by diameter, yet fourth most massive. Size of Uranus compared with the Earth Side by side comparison of the size of Uranus vs Earth Facts about Uranus William Herschel discovered Uranus in 1781. The planet is too dim to have been seen by ancient civilizations. Herschel himself believed that Uranus was a comet at first, but several years later it was confirmed as a planet – making Uranus the first planet discovered in modern history. The original name proposed by Herschel was “Georgian Sidus” after King George III but the scientific community didn’t take to it. Instead, Uranus was proposed and accepted by astronomer Johann Bode and it comes from ancient Greek god Ouranos. Uranus rotates on its axis once every 17 hours and 14 minutes. Like Venus, it turns in a retrograde direction which is opposite to the direction Earth and the other six planets turn.

It takes Uranus 84 Earth days to orbit the Sun. Its axis is at 98 degrees, which means it almost lies sideways as it orbits the Sun. This means that the north and south poles of Uranus lie near where the equator is on Earth. During parts of its orbit one or other of the poles directly face the Sun which means the planet gets around 42 years of direct sunlight followed by 42 years of darkness. A collision may have caused the unusual tilt of Uranus. The theory is that an Earth-sized planet may have collided with Uranus which forced its axis to drastically shift. Uranus wind speeds can reach up to 900 km per hour. This is roughly 560 miles per hour. The mass of Uranus is about 14.5 times the mass of Earth, making it the lightest of the four gas giants of the outer solar system. Uranus is often referred to as the “ice giant”. While it has a hydrogen and helium upper layer like the other gas giants, Uranus also has an icy mantle which surrounds its rock and iron core. The upper atmosphere of water, ammonia and methane ice crystals gives Uranus its distinctive pale blue color.

Uranus is the second least dense planet in the solar system, after Saturn. The Voyager 2 is the only spacecraft to have flown by Uranus. This happened in 1986 and it flew past the planet at a distance of around 81,500 km. This mission returned the very first close-up images of the planet, its ring system and its orbiting moons. Uranus has 13 presently known rings. All except two Uranian are extremely narrow – they are usually a few kilometres wide. It is believed that the rings are probably quite young. The matter within the rings is thought to be parts of a moon or moons that were shattered by high speed impacts with an object such as a comet or asteroid The chemical element Uranium, discovered in 1789, was named after the newly discovered planet Uranus. Uranus is the coldest planet in the solar system. The minimum surface temperature on Uranus is -224°C – making it the coldest of the eight planets. Its upper atmosphere is covered with a haze made mostly of methane which hides the storms taking place in its cloud decks. The Uranian moons are named for characters created by Alexander Pope and William Shakespeare.

For example, Oberan, Titania and Miranda. All these worlds are frozen with dark surfaces and some are a mixture of ice and rock. Of the Uranian moons, the most interesting is Miranda which has ice canyons, terraces and many strange looking surface area. More information and facts about Uranus Uranus has the distinction of being the first planet discovered in modern history. Actually, its discovery as a planet almost did not happen. In 1781, the astronomer William Herschel was charting the stars found in the Gemini constellation when he observed a disk-like object. His initial conclusion was that he had discovered a comet and reported his findings as such to the Royal Society of England. However, Herschel was puzzled when he calculated the object’s orbit. Instead of the more elliptical path occurring with comets, he found that it was much more circular. This observation, which was confirmed by other astronomers at the time, led Herschel to conclude that he had, in fact, discovered a new planet. Shortly thereafter, it was widely accepted that Herschel had discovered an unknown planet. As a result of his discovery, Herschel was given the privilege of naming the new planet.

The name he chose was Georgium Sidus, which is latin for Georgian Planet. He opted for this name to honor then king of England, George III. This name, however, was not widely accepted, and as a result others began to suggest names. The name Uranus was put forth in the tradition of naming planets after deities in Roman mythology. Over time the scientific community accepted this as the planet’s name. At present, the only planetary mission to visit Uranus is Voyager 2. This lone encounter, which occurred in 1986, provided a large amount of data and discoveries. The spacecraft took thousands of pictures of Uranus and its moons and rings. Although the images of the planet showed little other than the uniform blue-green color seen from Earth-based telescopes, other images revealed the presence of ten previously unknown moons and two new rings. At this time, no future missions are scheduled for Uranus. Atmosphere Due to its stark blue appearance, the Uranian atmospheric patterns have been much more difficult to observe than, say, those of Jupiter or even Saturn. Fortunately, the Hubble Space Telescope has provided much more insight into the structural nature of Uranus’ atmosphere.

Through more advanced imaging technologies than Earth-based telescopes or Voyager 2, Hubble has shown that there are latitudinal bands much like those found on the other gas giants. Additionally, the winds associated with these bands can blow in excess of 576 km/hr. The reason behind the monotonous atmospheric appearance is the composition of the top-most layer of the atmosphere. The visible cloud layers are composed primarily of methane, which absorbs those visible wavelengths corresponding to the color red. Thus, the reflected wavelengths are those of blue and green. Beneath this outer methane layer, the atmosphere is composed of roughly 83% hydrogen (H2) and 15% helium with trace amounts of methane and acetylene. This composition is similar to that of the other gas giants. Uranus’ atmosphere is drastically different in another regard, though. Whereas Jupiter and Saturn’s atmospheres are primarily gaseous, Uranus’ contains much more ice. This indicates that the Uranian atmosphere is extremely cold. In fact, at approximately -224° C, its atmosphere is the coldest found in the Solar System.

What is even more interesting is data indicates that this extreme temperature is constant globally, occurring even on the side that is not sunlit. Interior Uranus’ interior is thought to consist of two layers: a core and mantle. Current models suggest that the core is primarily composed of rock and ice and is approximately .55 times the mass of the Earth. The planet’s mantle is believed to be 8.01 x 1024 kg, or about 13.4 times the mass of the Earth. Furthermore, the mantle is composed of water, ammonia and other volatile elements. What distinguishes Uranus’ mantle from those of Jupiter and Saturn is that it is icy, though not in the traditional sense. Instead, the ice is very hot and thick. The mantle is 5,111 km thick. What is most surprising about Uranus’ interior and one of the most distinguishing features with respect to the other gas giants is that it does not emit more energy than it receives from the Sun . Considering that even Neptune , which is very similar in size to Uranus, produces approximately 2.6 times the amount of heat that it receives from the Sun, scientists are very intrigued by the low heat that Uranus generates.

There are two popular theories for this phenomenon. The first says that Uranus was struck by a large body, dispersing into space most of the heat that planets normally retain from their formations. The second theory claims that there is some barrier preventing the internal heat from making its way to the planet’s surface. Orbit & Rotation When Uranus was discovered it expanded the radius of the known Solar System by almost a factor of two. What this means is that, on average, Uranus’ orbit is about 2.87 x 109 km. The consequence of such an enormous distance is that it takes sunlight around two hours and forty minutes to reach Uranus&#8212that is almost twenty times as long as it takes sunlight to reach the Earth! This huge distance also means that a year on Uranus lasts almost 84 Earth years! At 0.0473, Uranus’ orbital eccentricity is just slightly less than that of Jupiter’s .0484, making it the fourth most circular orbit of all the planets.

The result of Uranus’ fairly small orbital eccentricity is that the difference between its perihelion of 2.74 x 109 km and aphelion of 3.01 x 109 km is just 2.71 x 108 km. Perhaps the most interesting thing about Uranus is how odd its rotation is compared to all of the other planets’. The axis of rotation for every planet other than Uranus is roughly perpendicular with their orbital plane. However, Uranus’ axis is tilted almost 98°, which effectively means that Uranus rotates on its side. The result of this is that Uranus’ north pole points at the Sun for half of its year, while the south pole points at the Sun the other half of its year! In other words, it is daytime on one Uranian hemispheres, while it is night time on the other for 42 Earth years at a time. Furthermore, due to this extreme rotation, Uranus does not have days like on other planets&#8212that is, the Sun doesn’t rise and set like on other planets.

The cause for this highly unusual axial tilt is theorized to be the effect of a large body striking Uranus with such force that it essentially knocked the planet over on its side. Rings Although Saturn’s rings have been well known for some time, it wasn’t until 1977 that the planetary rings surrounding Uranus were discovered. The reason behind this is twofold: their distance from the Earth and their low reflectivity of light. Nonetheless, the Voyager 2 spacecraft identified two more on its fly-by mission in 1986, followed by the Hubble Space Telescope discovery of two additional rings in 2005. The total number of known rings currently sits at thirteen, the largest and brightest of which is the epsilon ring. Uranus’ rings differ from those found around Saturn in both the size of its particles and the particles’ composition. First, the particles making up Saturn’s rings are small, with few larger than several meters in diameter, whereas Uranus’ rings contain many bodies up to twenty meters in diameter. Second, the particles of Saturn’s rings are largely composed of ice. Uranus’, however, are composed of both ice and considerable dust and debris.

Uranus Profile The asteroid belt lies between the orbits of which two planets? A. Earth and Mars B. Mars and Jupiter C. Jupiter and Saturn D. Saturn and Uranus You have new items in your feed. Click to view. Question and answer The asteroid belt lies between the orbits of which two planets? A. Earth and Mars B. Mars and Jupiter C. Jupiter and Saturn D. Saturn and Uranus The asteroid belt lies between the orbits of MARS AND JUPITER.

Question: Which planet lies between Jupiter and Uranus?
Answer: Saturn