Moving at the speed of light, how long would it take to go around the universe once?

Question

I just wanna know because I am curious about this.

Answer 1

The Universe is about 13.7 billion years old by latest estimations. So, the distance we can see is limited to a maximum of 13.7 billion light-years away. If you wanted to go visit that boundary, then travelling at the speed of light it would obviously take 13.7 billion years.

But that would not be "going around the universe once." It is most likely impossible to go around the universe once. It is currently accepted that the universe is INFINITE, so you cannot ever go around it once.

Not only is it infinite, but it's still getting bigger, and at an increasing rate. So you better get started on your journey ASAP.

P.S. Oh yeah, since you experience NOpassage of time AT ALL at the speed of light, I guess the other answer is "no time at all." This is a paradox! Of course, the rest of the universe would age infinitely.

Answer 2

Wow, it always blows my mind the way people answering these questions just throw around infinitys all willy-nilly.

You people have to be careful with infinitys. Infinately small becomes a black hole. Infinite Universes leave no where to expand and leave us scratching out heads on Red Shift.

I believe the shape of the Universe to be a four dimentional hypersphere, but that is subject to debate.

The Universe is finite and 13.5 Billion years old. This does not mean the Universe is 13.5 Light-years from the center to the edge, or 27 Billion light-years in diameter. The expanding edge of the Universe is not limited to the Speed of Light because it is not a particle. It is the expansion of EXISTANCE in the dimentions we recognise. Space/Time itself has no mass, which is what prevents acceleration to lightspeed.

So, no we don't know how many light years across the Universe is, but if you are traveling at the speed of light it doesn't matter. Your relative movment is experinced as instantanious no matter the distance because your relative time slows as you approch light speed. At light speed, time as you percive it stops and past light speed you will be traveling backwards in time.

So, the answer is 0, for you.

For an observer on Earth, it would take greater than or equal to 27 Billion years. The Sun will have swelled up and charred earth and shrunk back down into a white dwarf about 20 Billion years ago by the time you get back. You didn't age a day.

Answer 3

Assuming you are a photon, your trip around the universe would take no time at all. Since photons move at the speed of light, time stands still for them. They are everywhere at the same time, from their point of view.

Now if you are not talking about being a photon, then it isn't possible to reach the speed of light. You can theoretically get very close to it, but you can never achieve it. So, you could make your trip around the universe in any amount of time you wanted to, just by going as close to the speed of light as you like. If you were able to go a tiny tiny tiny tiny fraction below the speed of light, the trip would seem (from your point of view) to take nearly no time at all. This isn't counting the time to speed up and slow down, of course.

Answer 4

This is not very intuitive, but here goes:

If we use your reference of time - you could transverse the entire universe in zero time - even if the universe is infinite!
At the speed of light, time slows to a stop.

On earth, however, an observer using his clock and all of his ancestors would be long dead - along with our entire solar system - so it wouldn't be wise to think that you can return after such a momentous trip to a ticker tape parade!

(Obviously, there are numerous reasons that an object will never achieve the speed of light. But it is, none the less, interesting to speculate such journeys.)

Answer 5

You can't, the universe is infinite, there fore you could not go around it, But if you where to move at the speed of light, and the universe is approximately 13.7 or 13.8 billion years old, you could go to the rim and back in about 27.5 billion years. But if you really wanted to see the universe the way to do that would be worm hols or to fold space time, this way you lose no time at all and it is almost instant. So to answer your question you can't, but if we had the tech. to fold space you could theoretically. Good luck.

Answer 6

If it were possible, it would would take millions of human generations to accomplish that. It would take four hours traveling at the speed of light just to reach Pluto from Earth. It takes four years for the light of the nearest star (besides the sun) to reach earth.

Our galaxy, the Milkyway, is 100,000 lightyears across.

The nearest galaxy to us, Andromeda, is 2 million lightyears away.

There are probably between 125 billion to 500 billion galaxies in the universe.

The universe is approximately 156 million lightyears across.

So it would take 156 million years just to travel across the universe at the speed of light. And of course going around the universe would be much further/longer.

Answer 7

Well if the universe is 13.7 billion light years in all directions from the Big Bang, the radius is 13.7 billion light years.

Cirrcumfrence = 2 pi r = 86 billion light years around.

A light year is how far light travels in one year, so it would take 86 billion years.

Answer 8

If you could travel at the speed of light (the speed in vacuum) you could travel anywhere you wanted to instantly since length contraction says that all distances in the direction of travel at the speed of light go to zero. Of course many billions of years would go by here on earth for those you left behind (time dilation), but for you, it would seem instantaneous.

Answer 9

An infinite amount of time, given that the universe is expanding at the speed of light, so you'll never be able to catch the edge.

Answer 10

You will experience no passage of time but 26,000,000,000 earth years will have passed. The number is is based upon a round trip from Earth to the most distant quasar and assumes there is nothing beyond that point.