Is the universe infinite in size?Do we have evidence of other universes

Well, ..., Her are my answers:

1) The Universe is finite.
It started off with finite mass and energy. It neither creates new mass or destroys the old mass. Nor does it create or destroy energy. Even though it is currently expanding that expansion will one day stop and the universe will come to an end. The universe held no control over it's inception and creation, has no control over it's current state and cannot control it's future demise. I know it's an unpopular concept to grasp bu the universe is finite in energy, mass, and life cycle and that's all there is to it. See the links below:

2) There is no evidence for the existence other universes.
No matter how many times it occurs in science fiction there is not one shred of evidence for the existence of other universes. We can only observe about 3% to 4% of our own universe so we still have about 96% left to explore of this universe alone. Again, I know it's an unpopular thought but this universe is all we have and certainly the only one that you or I will ever know and as I mentioned before even it is doomed.

Actually, the WMAP shows the universe to have a flat topology which implies it could be infinite but the resolution of the WMAP allows for a 0.5% margin of error so the Universe could be finite or infinite. The WMAP also shows evidence of a neighboring universe and evidence have also been found in the Large Hadron Collider but it will take a year to two years to analyze the data.

The German astronomer Heinrich Wilhelm Olbers 200 years ago proved that the universe cannot be infinite in either time or space. That this is not better known and understood is a tribute to the quality of science education offered today.
There are theories which allow for multiple universes, but no definitive evidence either way

The correct answer is, we don't know. But I'd like to stress a mistake we do all the time: