How would be our Universe if Einstein was right?

[Time_Travel]

How would have been our Universe if Einstein was right?:(

Considering that he argued for non expanding Universe but Hubble's observations proved him wrong.

 

How would our Universe be "if the Universe was not expanding at all"?, assuming that if there is no expanding Universe then no dark energy or would it still be there?

[Janus]

Einstein didn't "argue" for a static universe, it was just the prevailing thought at the time he developed GR. He therefore added a "cosmological constant" to his equations to counter the tendency for a such a universe to collapse under its own gravitational pull.

 

Later, when Hubble discovered the expansion, making the cosmological constant mute, Einstein himself called it his greatest blunder.

 

The question now became whether or not the universe was massive enough for its gravitational pull to be able to eventually slow this expansion to a stop and re-collapse the universe at some far distant time.

 

Fast forward to the 1990's. Observations made to determine how fast gravity is slowing the expansion show that it is actually expanding at an accelerating rate. Not only is the universe's expansion not slowing, it is speeding up.

 

Interestingly, this brings us right back to Einstein's cosmological constant. Originally, it was given just the right value needed to hold up a static universe, but if the value is slightly different, it would lead to a runaway expansion such as we are now seeing.

 

So it might just turn out that Einstein was right, just not in a way that he expected.

[Time_Travel]

What i meant to say was how would our Universe be wrt physics if it really were static?

Since its not static we are seeing the Universe the way it looks now.

[Boerseun]

I suppose if everything else stays the same and the universe was static, you should see a gradual blueshifting as everything will begin to fall together due to gravitational attraction.

[Time_Travel]

If Gravity would have been pulling everything else then we cann't assume our Universe was never static

[Boerseun]

If Gravity would have been pulling everything else then we cann't assume our Universe was never static

...and you can't expect a serious answer if you shift the goalposts.

 

As per your original post:

How would our Universe be "if the Universe was not expanding at all"?

If that was the case, then the universe would be either static, or contracting. Those are the only options left "if the universe was not expanding at all". If the universe was indeed static, then you should see a gradual blueshift, because gravitational attraction will start a big collapse.

[Time_Travel]

...and you can't expect a serious answer if you shift the goalposts.

 

As per your original post:

 

If that was the case, then the universe would be either static, or contracting. Those are the only options left "if the universe was not expanding at all". If the universe was indeed static, then you should see a gradual blueshift, because gravitational attraction will start a big collapse.

 

Sorry . You totally misunderstood me and i am not shifting from goalpost. If we just assume Universe was static from the beginning just the way Einstein thought , how would it look . For example if the current Universe is static then how would the universe behave? Assuming that gravitation would not attract everything inside it and also assuming that dark energy does not cause run away expansion ( these assumptions are assumed to define a static Universe right).

[Boerseun]

If the universe was static, as per your question, then I suppose we can assume that the universe is infinite with an equal spread of mass in all directions, to infinity. Else the universe will collapse.

 

A couple of interesting conclusions could be drawn in that case. For instance, a static universe implies that matter must be created from somewhere at the same rate at which it is destroyed in order to maintain the static structure at the cosmic scale.

 

Also, in a static universe, you should see vastly different types and kinds of galaxies - because you will be able to see galaxies older than 15 billion years. You should see dead galaxies hundreds of billions of years old as well as young ones. Matter of fact, you should see ancient stars and very young ones in the same galaxy. Also, you shouldn't be seeing CMBR.

 

Another argument that predates Hubble's discovery that basically predicted an expanding universe with a definite origin somewhere in the past, is that if the universe was static, thereby implying that it's infinite both in space and time, every line of sight should terminate on the surface of a star. The night sky should be one solid wall of stellar fire. This is clearly not the case - but I suppose gives a good idea of what a static universe, infinite in space and time, should "look" like from Earth.

[Tormod]

...thereby implying that it's infinite both in space and time, every line of sight should terminate on the surface of a star. The night sky should be one solid wall of stellar fire. This is clearly not the case - but I suppose gives a good idea of what a static universe, infinite in space and time, should "look" like from Earth.

 

This is also known as Olber's paradox.

[sanctus]

I imagine you could still have some kind of dark energy, because there would be the need for something oppsing the gravitational attraction. Just not enough to make the universe's expansion accelerate, but always pushing to expand in exactly the same amount than gravity tries to pull together. Then we could add to the flatness problem, fine tuning &co why they are so perfectly balanced ;-)

[Pyrotex]

What i meant to say was how would our Universe be wrt physics if it really were static?

Since its not static we are seeing the Universe the way it looks now.

Are you familiar with Olber's Paradox? Olber asked the question, "why is the night sky dark?"

 

:cheer: :rolleyes: :hihi:

 

If the universe were static and infinite (or extremely large enough), then every straight line drawn from your eyes out into the night sky would eventually hit a star. And the star would have no significant red shift, and therefore would not be artificially dimmed by its rapid speed away from you.

 

And therefore, the night sky would NOT be dark. :phones:

[Time_Travel]

Are you familiar with Olber's Paradox? Olber asked the question, "why is the night sky dark?"

:shrug:

I haven't heard the Olber's Paradox until http://hypography.com/forums/astronomy-and-cosmology/22891-how-would-our-universe-if-einstein.html#post294853 Tormod mentioned about it in this link. yeah confused a little bit so popped that question.

 

 

 

 

If the universe were static and infinite (or extremely large enough), then every straight line drawn from your eyes out into the night sky would eventually hit a star. And the star would have no significant red shift, and therefore would not be artificially dimmed by its rapid speed away from you.

 

And therefore, the night sky would NOT be dark. :bouquet:

 

So according to You "if Hubble wouldn't have discovered Expanding Universe then Olber (olbers Paradox) would have did?"