Is universe infinite?
The short answer is we don't know for sure, but most likely it isn't. And todays most popular theories will suggest that it isn't. So is there a border somewhere? Well, according to the big bang theory, there is a border, but not only for matter. Big bang theory suggest that universe is expanding it's space-time, So imagine a glass full of water. Now answer the question - What's in the glass? Well.. one could say the glass is full with water. Correct! Now empty the glass and ask again, what's in the glass? Well now one could say the air is in the glass. Now imagine we pump out all the air that's in the glass. Now what's in the glass? Well one can clearly see that light shines though the glass, so light is in the glass? Correct. Now you cover the glass so light can't get though. What is now in the glass? You are absolutely correct - the space is in the glass. And it's that space that's expanding. According to Einstein space is directly tied