0
votes
1answer
33 views

Cosmological pressure and the expansion of the universe

I have a problem understanding the thoughts behind a basic assumption of cosmology. The Friedmann equations follow from Newton mechanics (probe mass at the surface of a sphere) and conservation of ...
3
votes
3answers
108 views

Proportion of dark matter/energy to other matters/energy at the beginning of the universe?

What was the proportion of dark matter/energy to other matters/energy at the moments after the beginning of the universe (standard Big Bang model)?
2
votes
1answer
80 views

Why do we need the concept of dark energy to explain the expansion of the universe?

Why can't the expansion of the universe be thought as the Big Bang itself still in progress? Why do we need to introduce dark energy? The Big Bang was powerful, and that explosion itself could still ...
0
votes
1answer
517 views

Lawrence Krauss' Theory of Origin

I don't understand how a vacuum, the absence of matter, can hold energy. How can it hold energy when Einstein proved that matter is energy? And a second related question; how does the energy in a ...