• Question: what is a black hole and what does it do

    Asked by arahman809 to Usman, Amy, Grant, Martin, Shawn on 8 Mar 2013. This question was also asked by ionalane, ella111, wasimaafsar.
    • Photo: Grant Kennedy

      Grant Kennedy answered on 8 Mar 2013:

      Basically it’s something with such strong gravity that nothing can get away from it, not even light!

      Mostly they just sit where they are and stuff falls onto them, making them even stronger. If you look at a picture of a galaxy, like this one
      http://apod.nasa.gov/apod/ap120518.html
      we think there’s always a really massive one in the middle.

    • Photo: Usman Kayani

      Usman Kayani answered on 8 Mar 2013:

      Anything is capable of becoming a blackhole! You, me, your computer, your school (but then you’ll never be able to escape it!)..the earth..etc. If you could somehow squeeze something (matter) into a really tiny space, it would become so dense that the force of gravity would pull anything down toward it and nothing, not even light can escape it. For earth, if you could squeeze the entire planet into the space of a sugar cube – it would become a blackhole.

      The gravity we have on earth keeps us from flying away (booo!) by keeping our feet on the ground, when we jump then we fall back down again. But its quite easy to beat gravity, although its constantly pulling us down its quite easy to pick something up from the floor and everytime you do that your actually working against the force of gravity. This is also why the earth can be seen from space, because the particles of light known as photons are able to escape the earths gravity since they move really really fast and are able to reach the eyes of anyone in space; the same reason is why we can see other planets, stars etc.

      Inside a blackhole the situation is not so nice, the surface gravity is so intense that nothing can beat it not even light; and because no light can escape the gravity we can’t actually see it because the photons of light will never reach our eyes, instead we see blackness. This is why its called a ‘black’ hole.

      There are two main types of blackholes; stellar and supermassive. Stellar blackholes are the ones made from the death of stars that are more heavier than the sun; atleast three times more. When the fuel that keeps a star going runs out, it will no longer be able to sustain itself and its entire stuff gets collapsed into a very very small space and it becomes a blackhole. Supermassive blackholes are thought to exist at the centre of every galaxy, far from being destructive they are now understood to be responsible for a lot of structure in our galaxy; perhaps we wouldn’t even exist without a supermassive blackhole at the centre of our galaxy – the milky way.

    • Photo: Shawn Domagal-Goldman

      Shawn Domagal-Goldman answered on 12 Mar 2013:

      The other answers here cover it! If you want to learn more, you should check out Neil deGrasee Tyson’s TV show appearances and his book, where he talks about black holes and what it would be like to enter one.

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