• Question: why in moon is no air

    Asked by lgaucas to David, Jonathan, Pete, Sam on 8 Jul 2012.
    • Photo: Pete Etchells

      Pete Etchells answered on 8 Jul 2012:

      That’s a good question! The moon doesn’t have an atmosphere that is comparable to the Earth’s, simply because it’s not big enough. Because of its size, the moon’s gravitational pull is too weak to hold onto any sort of meaningful atmosphere – the ‘escape velocity’ (or how fast you have to be going to get away from the pull of a planet or moon) is very low for the moon, and so it’s very easy for gases to fly out into space.