Mars is solar system planets One, yes solar system The fourth from inside out planet , of terrestrial planet , diameter approx earth The inclination angle and rotation period of the rotation axis are similar to that of the earth. One revolution is about twice the time of the earth's revolution. It is called "God of War" in the West mars ”In China“ bewilder ”。 The orange appearance is because Surface Hematite（ ferric oxide ）。 Mars is basically a desert planet ， Surface Sand dunes and gravels are all over, and there is no stable liquid state Water bodies. carbon dioxide The main atmosphere is thin and cold, and dust is suspended in it. Dust storms often occur every year. Water ice and dry ice The polar crown will grow and decline with the seasons. Distance from the sun: 778.3 million kilometers (480 million miles); Business cycle: 12 years; Equator diameter: 142984 km (88849 miles). Jupiter It is the largest and the fastest rotating planet , can hold 1300 earth 。 Saturn In ancient times, it was called Zhenxing or Filled Star, because Saturn's revolution period was about 29.5 years. In ancient China, there were 28 constellations. Saturn was almost in one constellations every year, which meant it could stop or fill the constellations, so it was called Zhenxing or Filled Star. 119300 km in diameter ( earth 9.5 times), yes solar system second Megaplanets 。 It's with its neighbors Jupiter Very similar, the surface is also liquid state The oceans of hydrogen and helium are also covered with thick clouds. Saturn The upper wind is raging, and the wind speed along the east-west direction can exceed 1600 kilometers per hour. Saturn The clouds above are caused by these strong winds, and there are a lot of crystalline ammonia in the clouds. Saturn Is the sixth farthest from the sun planet , also planets The second largest planet in China. Orbit: 1429400000 km (9.54 AU) from the sun
planet Diameter: 120536 km (equator) Mass: 5.69 * 10 ^ 26kg.
Uranus is the seventh star outward from the sun planet , on solar system Is the third largest volume (compared with Neptune Large), ranking fourth in quality (lighter than Neptune). His name comes from Uranus, the god of the sky in ancient Greek mythology（ Ο ὐ ρανός）， He is the father of Cronus and the grandfather of Zeus. Uranus is the first one discovered in modern times planet Although its brightness is visible to the naked eye, like the five traditional planets, it was not found by ancient observers because of its gloominess. William· herschel The Sir announced his discovery on March 13, 1781 solar system For the first time in modern history. This is also the first one discovered with a telescope planet 。 Neptune (Neptune) is the eighth star orbiting the sun planet , also solar system The fourth largest in celestial bodies (on diameter). Neptune Less than in diameter Uranus , but the quality is bigger than it. Basic data
Orbit of revolution: 4504000000 km (30.06 AU) from the sun
Rail inclination : 1.769 degrees planet Diameter: 49532km (equator) Mass: 1.0247e26kg
Rotation period : about 22 hours Revolution cycle: about 164.8 earth year Discovered by: Johann Galle
Discovery time: 1846
In ancient Roman mythology Neptune (Ancient Greek mythology: Poseidon) represents the sea god. Pluto, or Asteroid 134340 , Yes solar system The twelfth largest rotating around the sun celestial bodies 。 It was discovered in January 1930 and named after Pluto (Hades in Greek mythology), the Roman god of the underworld. At first, it was thought to be solar system One of Megaplanets , but on August 24, 2006 Bragg The 26th Session International Astronomical Union China adopted the fifth resolution to classify Pluto as dwarf planet （dwarf planet）。 Rocky comet
Rocky comets, unlike ordinary comets, are mainly composed of ice ， Comet The main component of is rock. Therefore, their gas release is unpredictable, not just in Freeze line Inside of. The reason for this is believed to be similar to the mud crack at the bottom of the dried lake bed. The loose small pieces on the surface will leave, and later will be Radiant pressure sweep And push away.
Sometimes, a celestial body can be wrongly identified as a rocky comet, such as P/2010 A2 , Yes Asteroid belt An asteroid that collides with another celestial body, causing debris of rock to follow it for a short time. 
Rocky comet
Rocky comet The only known example of a rocky comet is Phaethon , which Perihelion 0.14 (the point closest to the sun) AU , closer to the sun than any other asteroid that has been named. It is known that it will brighten in some normal situations, suggesting that it may release gas, and Sun Earth Relations Observatory The spacecraft once observed it ejecting dust. Some unnamed asteroids are closer to the sun than Phaethon, but the phenomenon of gas release has not been observed. However, this does not mean that they do not release gas. It may be that we have not observed the details of these releases.
