• Question: Why does the vacuum of space not take away our oxygen?

    Asked by anon-182214 on 22 Jun 2018.
    • Photo: Donna MacCallum

      Donna MacCallum answered on 22 Jun 2018:

      Again, I don’t know too much about space…good point about how the Earth manages to keep its air around it

    • Photo: Leo Beacroft

      Leo Beacroft answered on 22 Jun 2018:

      I think it’s to do with gravity. Although we might think of air as being weightless, the different atoms and molecules in the air, oxygen, nitrogen, carbon dioxide all have weight and so they’re attracted to the earth by gravity. I believe this is one of the reasons why only some planets have an atmosphere. If a planet is too small, the gravity won’t be strong enough to contain the gases, and they will float away into space. Fortunately for us this doesn’t happen on earth!

    • Photo: Joanne Sharpe

      Joanne Sharpe answered on 22 Jun 2018:

      Such a good question! I hadn’t even thought of this. So I did some googling and found an answer! The only reason we think of vacuums “sucking” in air is because of pressure. For example if you had a box and created a vacuum inside of it, there is nothing to exert pressure on the walls of the box, no molecules, nothing. Whereas, outside the box, there are air molecules pressing on the box, so if you poked a hole in the box, the air molecules would rush in to fill it and flow into the area of lower pressure. The air pressure on Earth is created by gravity, but as you go further up into the atmosphere, the air pressure decreases so by the time you get to the edge, there is no pressure that would force the air into the vacuum of space.

    • Photo: Ashley Akbari

      Ashley Akbari answered on 24 Jun 2018:

      Not an expert on this one, but some good answer from Leo and Jo

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