If the big bang happened 13.8 billion years ago, and the universe is 93 billion light years in diameter, how did the universe expand faster than light?
In: Physics
The universe currently **is** expanding faster than light. Well at least **some part** of it; what’s outside the observable universe
Well, we aren’t actually sure that the universe ends with what we can see. We just ran the simulation backward to figure out how long it took to go from A to B. Okay, it’s not nearly that simple but that’s the gist of it.
The farther away something is, the more space between us that there is to expand. If something is far enough away, the cumulative expansion of all the space between those things will be faster than light.
In the distant future, dark matter will condense our galactic neighborhood into one giant galaxy. And the other giant galaxies will start expanding away due to dark energy until all the galaxies are too far away from each other that the light never reaches to other galaxies and every galaxy will think it’s alone.
The stuff in space isn’t moving faster than light. The space itself is. The big bang wasn’t an explosion that propelled everything outwards. It’s the expansion of space itself.
Latest Answers