What Happens to the Universe if Omega Equals Exactly 1?

  • Thread starter Thread starter cosmic time
  • Start date Start date
  • Tags Tags
    Omega
AI Thread Summary
If Omega equals exactly 1, the universe's fate is debated, as it cannot end in a big crunch or a big freeze. Instead, it would reach a state of asymptotic stationarity, expanding forever at a decreasing rate if no dark energy is present. However, current theories suggest that while Omega is approximately 1, the universe is dominated by dark energy, leading to accelerated expansion. This means that in practical terms, both Omega equal to 1 and less than 1 result in a scenario where the universe expands indefinitely. The discussion highlights the complexities and paradoxes surrounding the implications of Omega's value.
cosmic time
Messages
9
Reaction score
0
If Omega was exactly 1...

We know if the value of omega (the average mass of all matter int he universe was) was more than 1, the ultimate fate of our universe is the big crunch; also if omga was less than one, there wouldn't be enough gravitational pull to bring all matter back, however will expand forever, and will end in a big freeze.
I'm thinking if Omega was exactly 1, what's the final fate, it can't end in a crunch, or a freeze, or it can't be exactly one. It'll have to be a midway point between a freeze and a crunch, this can be used as a paradox, as there is no logical answer to my knowledge.
 
Astronomy news on Phys.org
If \Omega_m=1 and there's no dark energy or cosmological constant, then the universe asymptotically approaches stationarity as time approaches infinity. In other words, it expands forever, but at an ever slower rate. However, the most popular theory of the universe right now gives the following:

\Omega = 1

\Omega_m \simeq 0.3

\Omega_{\Lambda} \simeq 0.7

That is, we think that \Omega = 1, but the dominant component has a negative pressure. In this scenario, we expect the universe to expand forever and at an accelerated rate.
 
So, for all practical purposes :wink: and ignoring Dark Energy, omega =1 and < 1 gives you the same end-of-universe scenario.

Welcome to Physics Forums!
 
o I am sorry I was referring to the value of lambda and omega as one...:smile:
 
Publication: Redox-driven mineral and organic associations in Jezero Crater, Mars Article: NASA Says Mars Rover Discovered Potential Biosignature Last Year Press conference The ~100 authors don't find a good way this could have formed without life, but also can't rule it out. Now that they have shared their findings with the larger community someone else might find an explanation - or maybe it was actually made by life.
TL;DR Summary: In 3 years, the Square Kilometre Array (SKA) telescope (or rather, a system of telescopes) should be put into operation. In case of failure to detect alien signals, it will further expand the radius of the so-called silence (or rather, radio silence) of the Universe. Is there any sense in this or is blissful ignorance better? In 3 years, the Square Kilometre Array (SKA) telescope (or rather, a system of telescopes) should be put into operation. In case of failure to detect...
This thread is dedicated to the beauty and awesomeness of our Universe. If you feel like it, please share video clips and photos (or nice animations) of space and objects in space in this thread. Your posts, clips and photos may by all means include scientific information; that does not make it less beautiful to me (n.b. the posts must of course comply with the PF guidelines, i.e. regarding science, only mainstream science is allowed, fringe/pseudoscience is not allowed). n.b. I start this...
Back
Top