Apparently, a great deal of dark, unseen material exists, whose gravitational pull is responsible for the motions of the stars and galaxies that we see.
The Origin Of The Universe: Science Masters Series (ed. Basic Books, 2014) - ISBN: 9780465066889
Apparently, a great deal of dark, unseen material exists, whose gravitational pull is responsible for the motions of the stars and galaxies that we see.
The Origin Of The Universe: Science Masters Series (ed. Basic Books, 2014) - ISBN: 9780465066889