In the inner solar system, only substances with very high melting points would have remained solid. All the rest would have vaoprized. So the inner solar system objects are made of iron, silicon, magnesium, sulfer, aluminum, calcium and nickel. Many of these were present in compounds with oxygen. There were relatively few elements of any other kind in a solid state to form the inner planets.
Like Jupiter, it is mostly made up of hydrogen and helium that surround a dense core and was also tracked by ancient cultures. Its atmosphere is similar to Jupiter's. Uranus has a radius about four times that of Earth's. It is the only planet tilted on its side, and it also rotates backward relative to every planet but Venus, implying a huge collision disrupted it long ago.
The planet has 27 moons, and its atmosphere is made up of hydrogen, helium and methane, according to NASA. It was discovered by William Herschel in Neptune also has a radius about four times that of Earth's. Like Uranus, its atmosphere is mostly made up of hydrogen, helium and methane. It has 13 confirmed moons and an additional one awaiting confirmation, according to NASA. It was discovered by several people in Super-Earths: Scientists have found a multitude of "super-Earths" planets between the size of Earth and Neptune in other solar systems.
There are no known super-Earths in our own solar system, although some scientists speculate there may be a "Planet Nine" lurking in the outer reaches of our solar system. Scientists are studying this category of planets to learn whether super-Earths are more like small giant planets or big terrestrial planets.
Astronomers think the giants first formed as rocky and icy planets similar to terrestrial planets. However, the size of the cores allowed these planets particularly Jupiter and Saturn to grab hydrogen and helium out of the gas cloud from which the sun was condensing, before the sun formed and blew most of the gas away.
Since Uranus and Neptune are smaller and have bigger orbits, it was harder for them to collect hydrogen and helium as efficiently as Jupiter and Saturn. The rings look flat because the particles all orbit in essentially the same plane.
The rings are located closer to the planets than any of their moderately sized or large moons, but the inner edge of the rings is still well above the planet's cloud tops. Why are the jovian planets so different from the terrestrial planets? We can trace almost all the differences to the formation of the solar system.
The frost line marked an important dividing point in the solar nebula. Within the frost line, temperatures were too high for hydrogen ices to form. The only solid particles were made of metal and rock. Beyond the frost line, where hydrogen compounds could condense, the solid particles included ices as well as metal and rock.
While terrestrial planets accreted from planetesimals made of rocks and metals, they ended up too small to capture significant amounts of the abundant hydrogen and helium gas in the solar nebula. The jovian planets, however, formed farther from the Sun where ices and rocks were plentiful. The cores accreted rapidly into large clumps of ice and rock. Its size strongly indicates that it is a gas-dominated planet.
The discovery offers hope for finding more young hot Jupiters and learning more about how planets form throughout the universe.
There are three main hypotheses for how hot Jupiters get so close to their parent stars. One is that they simply form there and stay put. But it's hard to imagine planets forming in such an intense environment. Not only would the scorching heat vaporize most materials, but young stars frequently erupt with massive explosions and stellar winds, potentially dispersing emerging planets. It could be more likely that gas giants develop farther from their parent star, past a boundary called the snow line, where it's cool enough for ice and other solid materials to form.
Jupiter-like planets are composed almost entirely of gas, but they contain solid cores. It would be easier for those cores to form past the snow line, where frozen materials could cling together like a growing snowball. The other two hypotheses assume this is the case, and that hot Jupiters then wander closer to their stars. But what would be the cause and timing of the migration? One idea posits that hot Jupiters begin their journey early in the planetary system's history while the star is still surrounded by the disk of gas and dust from which both it and the planet formed.
In this scenario, the gravity of the disk interacting with the mass of the planet could interrupt the gas giant's orbit and cause it to migrate inward.
The third hypothesis maintains that hot Jupiters get close to their star later, when the gravity of other planets around the star can drive the migration.
The fact that HIP b is already so close to its star so early after its formation indicates that this third hypothesis probably doesn't apply in this case. But one young hot Jupiter isn't enough to settle the debate on how they all form.
Located less than 32 light-years from Earth, AU Microscopii is among the youngest planetary systems ever observed by astronomers, and its star throws vicious temper tantrums!
Weather here is deadly. The cobalt color comes from a hazy, blow-torched atmosphere containing clouds laced with glass. In , astronomers using NASA's Spitzer Space Telescope found evidence showing that gas-giant planets form quickly, within the first 10 million years of a Sun-like star's life.
Gas giants could get their start in the gas-rich debris disk that surrounds a young star. A core produced by collisions among asteroids and comets provides a seed, and when this core reaches sufficient mass, its gravitational pull rapidly attracts gas from the disk to form the planet. Scientists using Spitzer and ground-based telescopes searched for traces of gas around 15 different Sun-like stars, most with ages ranging from 3 million to 30 million years.
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