Expert: Jayendra Upadhye - 5/18/2006

Question
I am not science student at all, so i'll render apologise if my questions sounds alittle bit elementry.First of all, what is the hierarchy of space formation, is it planets, then galaxies, then solar system or what? (2) How many planets, solar systems, galaxies and stars are there?

Answer
Ibrahim!
I accept your apology, but would it not be nice if you had been into science, muslims need to be more into science!

1 - There is no hierarchy!
Right after the Big Bang, when the universe had cooled sufficiently for elementary hydrogen to exist in a stable form, stars, planets and galaxies started to coalesce!
[Only, the initial planets would all be hydrogen!, for the higher elements all owe their existence to the supernovas that would come a few 100 million years later].
Just as we cannot say a child was born first then the cells in his body, in the same fashion, the galaxy, the stars, and the planets all owe their existence to each other. They were formed concurrently!

But the age of the universe may be more than the age of its individual constituents. Just as we live longer than the cells in our body do. galaxies live longer than the individual stars making them.

2 - The only answer is "countless"!
We can only estimate, and still we would be wildly off the mark, regarding on how many galaxies , stars and planets there are in the universe!

Hope that suffices.
Jayen