What are the difference between Black holes and White holes?
We need to think about black holes before we talk about white holes. How do we know black holes exist? Well, we have two kinds of proof. Firstly, we have real, hard evidence from telescopes. Telescopes have been used to observe light emitting by material in orbit around something dark (that we can’t see with telescopes) and very heavy. These dark heavy objects seem to be very small relative to objects of similar or greater mass that we can see. These dark, massive objects are probably black holes. Secondly, we have a really good theory of gravity, which has been well-tested, which predicts that we should see such objects in the universe. So where do white holes come in? Well, the theory of gravity that we have (Einstein’s General Relativity), predicts black holes as a solution to a set of equations. Solutions to Einstein’s equations can have a “+” (plus or ‘positive’) or “-” (minus or ‘negative’) sign in front of them. We see this sort of thing all the time in mathematics. The solution
