how does a black whole form?

Question: how does a black whole form?
- Keywords:
  black holes
Asked by Esmee.C to Daniel, Hannah, Maggie, Ry, Scott on 6 Nov 2017.
- Ry Cutter answered on 6 Nov 2017:
  
  There are two main ways black holes form:
  1.) Black holes are born when a massive star (about three times our sun’s mass) uses up all of its fuel. The star collapses in a big implosion pushing all the electrons and protons together making lots of neutrons that all tightly packed together. If the star isn’t heavy enough it’ll make a neutron star. However, if it’s dense enough the gravitational field will be powerful enough to stop light escaping! That’s a black hole.
  
  2.)Neutron stars can turn into black holes by getting more mass. This can be from a poor passerby star that gets sucked up, or by a neutron star merger (two neutron stars colliding).
  
  Both of these ways come with amazing firework displays called supernova and kilonova.
  
  Cool Question,
  
  Ryan
- Scott Melville answered on 6 Nov 2017:
  
  The heavier a star is, the harder it is to run away (because the pull of gravity is so strong). If a star gets heavy enough, then not even light can run away (and light runs pretty fast!). This creates a black hole – it looks black to us because no light can come out. They float around space swallowing up other stars and planets, and occasionally they bump into each other, and fuse to become an even bigger black hole. It’s so loud when two of these things crash into each other, we recently heard the ‘bang’ with an experiment called LIGO 🙂
- Daniel Williams answered on 6 Nov 2017:
  
  A black hole gets made when lots of heavy stuff all clumps together in one place in a very small volume. That makes something very very dense.
  
  Heavy things make space bend around them. The sun makes space bend around it a bit, and that’s why the Earth and the other planets orbit around it. Black holes are much much denser than the sun (they’re both heavier and smaller) and that means that they bend space a lot more.
  
  If you bend space enough it can make something which is a bit like a deep hole; it’s impossible to get out of that hole, because the sides are so steep. If the sides are so steep that even light can’t get out (that’s important, because light travels faster than anything else in the universe, so is better than anything else at getting out of holes) then it will look completely black. That’s what we call a black hole.
  
  There are different ways of making a black hole. They can be made when a very large star runs out of fuel, and explodes as a “supernova” (a really big explosion) and the bit in the middle collapses in on itself. We also think that they also got made as part of the big bang: those black holes might have spent all of their lives crashing into other black holes, and that makes even bigger black holes. Those collisions between black holes are what we look for with gravitational wave detectors.
- Maggie Lieu answered on 6 Nov 2017:
  
  what they said ^
- Hannah Middleton answered on 6 Nov 2017:
  
  Just like the others said! Some black holes are formed from dead stars (those ones are several times the mass of our Sun). But other bigger black holes are much older and live in the very centre of galaxies. In the middle of our galaxy there is a black hole a million times more massive than our Sun (in Sagatarius A*). Astronomers think that super massive black holes live in the middle of most big galaxies. These huge black holes probably grow when galaxies collide – the black holes from each of them merge together and make new bigger black holes. But this is one type of black hole collision that astrophysicists have not observed yet (we have detected black hole collisions which where about 30 times the mass of the Sun), and hope to detect super massive black holes orbiting each other in the future!

Question: how does a black whole form?

Comments