I like the way you write; it's very clear. Even though there are some mistakes, most of the text is easy to understand.
I have a couple of remarks. Please try to rewrite your text according to them.
1) Remember that "hot" is not a noun. It's an adjective. You used it as a noun in more than one place.
2) "Space around the black hole is usually colder." Colder than what?
3) "black hole has a lower temperature." Lower than what?
4) "Remember hot flows to colder object?" How do we make questions in English?
5) There is a number of simple grammar mistakes in the text. I think you are able to spot them yourself.
I'm sure someone will correct your rewritten text. (They may even do this before you rewrite it!)
- For Teachers