If you are big enough planet, like Jupiter or Saturn, you kept the atmosphere that was the remnants of the gas in the solar nebula when the planets were formed (mostly hydrogen and helium). The smaller, inner planets probably got their atmospheres from the outgassing that occurred as they cooled down (volcanoes).
Do inner planets have little to no atmosphere?
Explanation: Of all the inner planets, Mercury, Venus, Earth and Mars, Mercury is the only planet known that does not have any atmosphere, mainly due to its proximity to the Sun.
Which planet has a no atmosphere?
Instead of an atmosphere, Mercury possesses a thin exosphere made up of atoms blasted off the surface by the solar wind and striking meteoroids. Mercury’s exosphere is composed mostly of oxygen, sodium, hydrogen, helium, and potassium.
What does it mean when a planet has no atmosphere?
If there was a substantial atmosphere present on the planet, then the hot air from one side would generate winds that transfer heat across the planet’s surface. But with a lack of atmosphere, there would be no air to transfer the heat around.
Why do planets have an atmosphere?
A: Planets and their atmospheres come from the same material as their parent star, which forms from a nebula of dust and gas. … Its increasing radiation blows the lightweight hydrogen and helium from the atmosphere of any planet without enough mass (and, thus, gravity) to hold onto it.
Why does Venus have no atmosphere?
Due to the lack of the intrinsic magnetic field on Venus, the solar wind penetrates relatively deep into the planetary exosphere and causes substantial atmosphere loss.
Does all planets have atmosphere?
For starters, it should be noted that every planet in the Solar System has an atmosphere of one kind or another. And these range from incredibly thin and tenuous (such as Mercury’s “exosphere”) to the incredibly dense and powerful – which is the case for all of the gas giants.
Why there is no atmosphere in outer space?
This is because there is no air in space – it is a vacuum. Sound waves cannot travel through a vacuum. ‘Outer space’ begins about 100 km above the Earth, where the shell of air around our planet disappears. … Even the emptiest parts of space contain at least a few hundred atoms or molecules per cubic metre.
What is the atmosphere of the planets?
The terrestrial planets are rich in heavier gases and gaseous compounds, such as carbon dioxide, nitrogen, oxygen, ozone, and argon. In contrast, the gas giant atmospheres are composed mostly of hydrogen and helium. The atmospheres of at least the inner planets has evolved since they formed.
Why are all planets spheres?
Planets are round because their gravitational field acts as though it originates from the center of the body and pulls everything toward it. … The only way to get all the mass as close to planet’s center of gravity as possible is to form a sphere. The technical name for this process is “isostatic adjustment.”
Why is Earth’s atmosphere different from other planets?
The main difference between the Earth’s atmosphere and the one of other planets (such as Venus and Mars) is that about 21% of it is composed by oxygen. Oxygen is a key element to sustain any complex life form on the planet. … Both produce oxygen by means of photosynthesis.