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?

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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

24 Answers

Anonymous 0 Comments

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.

Anonymous 0 Comments

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.

Anonymous 0 Comments

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.

Anonymous 0 Comments

The universe currently **is** expanding faster than light. Well at least **some part** of it; what’s outside the observable universe

Anonymous 0 Comments

Imagine the universe like the surface of a balloon. This universe has an incredibly slow speed limit of 1 centimeter per hour over its surface. The balloon is also inflating so that two dots that are sitting still on the surface are actually moving apart faster than 1 cm per hour.

That’s what the universe is doing, except in 3 dimensions instead of 2. The really crazy thing is that the expansion is *accelerating*, and we don’t know exactly why.

Anonymous 0 Comments

Imagine two cars accelerating in opposite directions from one another at equal speed. Imagine they both travel for one mile and then stop. The distance between the cars is now two miles. The speed at which the distance between the two cars increases is twice as fast as the speed of either car individually.

The same thing is happening with the Universe. It’s not that the matter itself is travelling faster than light; it’s that the matter at one end of the Universe is accelerating away from the matter at the opposite end faster than light itself can travel through space.

Anonymous 0 Comments

Draw some dots on a deflated balloon, then put some ants on the balloon. The ants can move at some max speed, which we’ll call C, and they walk between the dots because they’re made of food.

Now start inflating the balloon. If you do it fast enough, the distance between an ant and the next dot will increase rather than decreasing, even though they are walking towards the dot. The space between the ant and the dot is expanding faster than C.

Now imagine the surface of the balloon is 3 dimensional, and that it is expanding along a fourth dimension. That’s how the universe expands.

Anonymous 0 Comments

Nothing can travel faster than light. But expansion is not travel. Galaxies, clusters and superclusters are not (generally) traveling away from each other, the space between them is just getting wider.

Anonymous 0 Comments

Space itself is expanding. Nothing can move through space faster than light. But space can do whatever it wants.

Anonymous 0 Comments

basically the speed of light is the speed limit for “information” to travel through the universe. Think of it as anything that could be measured is considered “information”

Space itself is nothing, so it doesn’t count as “information” and can then pass the speed of light.

Another example is if you take a giant pair of scissors with light-year long blades. If you close the scissors at any speed where it takes less than a year to close, then the point where the blades touch will move along the blades faster than the speed of light.

The point itself is not anything that could be measured so it is “informationless” and can pass the speed of light”

I don’t know how much that helps, it’s how it was explained to me though.