Read the following para and answer the questions.
Scientists have figured out that the stars are actually part of larger groups called galaxies and that there are millions of such galaxies in the universe. Now, they are of the view that the universe itself started some 13.7 billion years ago with a ‘Big Bang’ and that it may end several billion years later.
1) What is a galaxy?
2) When was the ‘Big Bang’ happened?
3) How many galaxies are contemplated by scientists?
4) When would be the end of the universe?