The moon is one of the heavenly bodies that do not have gravity and hence lack atmosphere. It is also worth noting that the moon does not emit light of its own but rather reflects the sun's light.
A lot of planets don't have an atmosphere, and a lot of them do, with varying intensities and contents. But as for the planets that don't, the reason they don't is because the planet doesn't have enough gravity to hold anything within it, such as gasses or liquids.
Every planet in the solar system has some kind of atmosphere, although there is contention about Mercury because it's incredibly thin. Some planetary scientists don't consider it to have a true atmosphere and refer to its "exosphere" instead.
Mercury
Earth's moon
Mercury
Mercury, almost all the moons and the asteroids.
Many moons. In fact, most moons do not have an atmosphere. For example, our Moon certainly does not have an atmosphere. Titan, however, is a moon of Saturn and it does have an atmosphere.
Mercury
The moon has gravity, but it is much weaker than the gravity on Earth. It is not enough to hold onto an atmosphere.
earth gravity is strong enough to hold down the atmosphere
gravity doesnt, it is water and heat that does
The Earth has an atmosphere because it has the gravity necessary to keep the gases from floating off into space. The more mass a planet has, the more gravity it has, and the more gravity it has, the thicker an atmosphere it can sustain.
it doesnt.
One word- gravity. Mercury is just simply not massive enough to generate the gravity required to hold gases close enough to the surface to create an atmosphere.
The earths gravity. The more mass a body has, the more gravity, The Earth has enough mass to hold an atmosphere. The Moon, on the other hand, is not massive enough, and so does not have a high enough gravity, which prevents it from holding an atmosphere.
Nercury
The atmosphere is held in place by the earth's gravity. Gravity is related to mass, the more mass a planet has, the more gravity. A much smaller planet like mercury or a body such as the moon will have less gravity, not enough to hold an atmosphere - the gravity is not strong enough to prevent the gas particles from escaping into space.
Because it does not have enough gravity to "hold" onto an atmosphere.
Because it doesn't have enough gravity to hold the atmosphere down? :D
The moon has gravity, but it is much weaker than the gravity on Earth. It is not enough to hold onto an atmosphere.
The moon's gravity is not strong enough to support an atmosphere.
The Moon does not have enough gravity to retain an atmosphere.
No. They do not have enough gravity to hold on to the gasses.
The asteroid belt, is a "collection" of asteroids circling the Sun in between the orbits of Mars and Jupiter. A collection cannot have an atmosphere. A single asteroid does not have enough mass to "hold" on to an atmosphere.
No. The gravity on Venus is only slightly less than it is on Earth. Venus has an atmosphere about 90 times denser than Earth's.