# If Omega was exactly 1

1. Nov 3, 2005

### cosmic time

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 cant end in a crunch, or a freeze, or it cant 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.

2. Nov 3, 2005

### SpaceTiger

Staff Emeritus
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.

3. Nov 4, 2005

### Phobos

Staff Emeritus
So, for all practical purposes and ignoring Dark Energy, omega =1 and < 1 gives you the same end-of-universe scenario.

Welcome to Physics Forums!

4. Nov 7, 2005

### cosmic time

o im sorry I was referring to the value of lambda and omega as one....:rofl: