The universe is everything
that exists. In modern cosmology, that means all the energy, all the material, and even
space and time itself. The best estimates put the age of the universe at somewhere between
12 and 20 billion years, with the most recent evidence favoring a younger universe.
The universe is expanding, meaning that space-time itself is expanding. We know this because all the objects that we can see beyond our own galaxy are moving away from us at great speed. The objects most distant from us are moving away at the fastest speeds. MORE!