• Question: Is space dark or is their just nothing to allow us to see the light e.g attoms and things?

    Asked by dependingontheweather to Meeks, Pete, Stephen, Steve, Tom on 23 Jun 2010 in Categories: .
    • Photo: Steve Roser

      Steve Roser answered on 18 Jun 2010:

      There was an idea some time ago that if there is an infinite number of stars, then we should look out on a totally bright sky all the time, since the light doesn’t ‘wear out’ as it travels towards us. So there must be gaps or things absorbing the light – I think there is this stuff ‘dark matter’ which hoovers up light which we don’t really know what it is…

    • Photo: Stephen Curry

      Stephen Curry answered on 18 Jun 2010:

      The only things that are visible to us are things that reflect or scatter light. So space (the bit between the planets, stars etc) is dark because it is empty – there is nothing for light to bounce off.

    • Photo: Tom Hartley

      Tom Hartley answered on 18 Jun 2010:

      There could be some mistakes in all this, so I’d be interested to read what the other’s say. But I’ll have a go.

      Space is more or less empty (with some dust that sometimes blocks light from distant stars)

      There are big gaps between the stars and they are getting bigger.

      Light from stars very far away hasn’t had time to reach us yet.

      Only a small proportion of the light from a star reaches us (because most is going off in all the other possible directions) – so the further away you are from a star the less light reaches you (I think).

      So there is an absence of light coming from some directions (where the stars are too far away or behind dust), and that’s why (I think) most of the night sky looks dark (i.e. why there are gaps between the stars).

      I also think it’s quite bright in space in the sense that the sun (if you are anywhere near it) is not passing through the atmosphere and is much more intense than it appear on Earth.

    • Photo: Pete Edwards

      Pete Edwards answered on 18 Jun 2010:

      We only see things if they reflect or scatter light from a source (eg the Sun) which then enters our eyes. Space (the bits between the planets, stars and galaxies) is dark because it is pretty much a vacuum – it contains very little and there is nothing for light to bounce off.

    • Photo: Marieke Navin

      Marieke Navin answered on 23 Jun 2010:

      The other answers here are just great and I totally agree – space it pretty empty so not much for light to bounce off!