I Expanding Universe without dark energy

[takacszoltan87]

TL;DR Summary

Question of a noob.

Dear all!

I'm not a scientist, but I'm thinking about something, I'm curious, is it possible to believe that our universe is in a vacuum, the stars are moving away a not because of the dark energy but becouse it behave like a luffbaloon in a vacoom. Sorry for noob questions.

 

[Ibix]

The stars don't move away. Only distant galaxies do.

Yes, they move apart even in models without dark energy. However, no matter how you play around with the mix of matter and radiation in the model universe you cannot get the expansion profile to match the universe we see around us. To get what we see you have to add dark energy to the models.

So although you can have an expanding universe without dark energy, it does not appear to be the one we live in.

 

[ohwilleke]

becouse it behave like a luffbaloon in a vacoom

That behavior is driven by the pressure of the gas inside a balloon. In a vacuum there is no pressure between stars and other celestial objects that aren't effectively in contact with each other, and there is no material outer boundary to press against.

 

[takacszoltan87]

TL;DR Summary: Question of a noob.

Dear all!

I'm not a scientist, but I'm thinking about something, I'm curious, is it possible to believe that our universe is in a vacuum, the stars are moving away a not because of the dark energy but becouse it behave like a luffbaloon in a vacoom. Sorry for noob questions.

Okay, Thank you very much for everyone, it make sense!