How can the observable universe be over 90 billion light-years across when the universe is only 14 billion years old?

Question

How can the observable universe be over 90 billion light-years across when the universe is only 14 billion years old?

In: Physics

Answer 1

I would recommend reading[this](https://medium.com/starts-with-a-bang/how-is-the-universe-bigger-than-its-age-7a95cd59c605) as it explains it quite well.

TLDR: The universe expanding from everywhere, think of a balloon being inflated with dots drawn over it, from each dot, everything appears to be getting further away from each other.

Now assume a planet is travelling at the speed of light in one direction, and another is travelling at light speed in the opposite direction, the distance between them will be twice the speed of light multiplied by time. This could mean that in 1 year, two planets travelling at light speed could be 2 light years apart. This is similar to what happens with the universe, which is why it isn’t correct to just assume that the size of the universe < it’s age in light years.