Why doesn't the moon have an atmosphere? Other moons like Saturn's Titan have them.?

Question

What is the moon's escape velocity? Could air really move that fast to escape?

Answer 1

The moon might have had some atmosphere but the solar wind slams into it at speeds of maybe 800km/s give or take a bit according to the solar activity. This blows any atmosphere out into space easily under the low gravity conditions.

The earth is luckier as it has a magnetic field which deflects the solar wind and protects our atmosphere otherwise we would not have much air left, like Mars.

Answer 2

The Moon could have an atmosphere, if it were placed there by mankind. I have read that if an Earth type 1.0 Bar atmosphere of Oxygen/Nitrogen were created on the Moon, that it would have a half life of roughly 1 million years. The lunar escape velocity is 2.38 Km/ sec which is far larger than the average velocity of the average air molecule, which is roughly 300 m/sec. An artificial magnetic field added to the moon could double or triple the half life of an Earth type atmosphere, and would not be that difficult to construct. But who needs the Moon? It is said to be "the slag heap of the solar system". On to Mars, man! On to Mars! Who wants to live in a place that has 15 Earth days of continuous daylight, followed by 15 days of total darkness? The weather channel would have a heyday in a place like that! Think of the highs and lows, and the weather systems that would result!
P.S. The escape velocity from Titan is nearly identical to Earth's moon. Don't believe all of that nonsense above about Titan having more gravity. Titan is larger, but less dense. The two compensate each other yielding a rough equality.

Answer 3

Lunar escape velocity is 2.38km/s, and that's easily low enough for gas molecules to reach escape velocity. Titan has two advantages over the Moon for retaining an atmosphere. The first is its size, and the second is that it is much much colder. With the comparatively feeble heat from the sun at that distance the molecules in its atmosphere are moving much more slowly than they would were it located near the Moon.

Answer 4

No. Getting resources from space (for use on Earth) is always more expensive than collecting them from the Earth, even if they are rare and expensive. To give you an idea why, consider the Saturn 5 rocket. It used a payload of over 100 tons of fuel and oxidiser JUST to get the 15 tons of the Apollo spacecraft into low Earth orbit. Another 40 tons or so was utilised to achieve lunar transfer orbit. The amount of fuel you would use to achieve complete escape from the Earth-moon system would be greater than this and this does not even include what you would use to enter and escape from the gravity well of Saturn, nevermind landing and taking off from Titan. Regardless of how much rocketry has advanced in the last 40 years and assuming all your ordnance except for fuel is reusable, you can appreciate why this is not feasible and why we do not yet have tankers in space!

Answer 5

The Moon is too small to retain anything but the most tenuous trace of an atmosphere. Its gravitational attraction is too low for air molecules to hang around. Titan is significantly larger than the Moon, and has enough gravitational force to maintain a thick atmosphere. And yes, individual air molecules move very quickly, but they average out so we're unaware of their movement.

Answer 6

The moon never had an atmosphere. It formed after a Mars-sized object impacted Earth billions of years ago. The debris from that collision gradually formed itself into our moon.

Lunar escape velocity - 2.38km/s (..5323 mph..)

Answer 7

The Moon is in synchronous rotation, meaning that it keeps nearly the same face turned away from Earth at all times. Early in the Moon's history, its rotation slowed and became locked in this configuration as a result of frictional effects associated with tidal deformations caused by the Earth.[5] Nevertheless, small variations resulting from the eccentricity of the lunar orbit, termed librations, allow a total of about 59 per cent of the lunar surface to be visible from Earth at one time or another.The side of the Moon that faces Earth is called the near side, and the opposite side the far side. The far side should not be confused with the dark side, which is the hemisphere that is not being illuminated by the Sun at a given moment. The far side of the Moon was first photographed by the Soviet probe Luna 3 in 1959. One distinguishing feature of the far side is its almost complete lack of maria.