how big is the universe?

Answer 1

Although it is only 13.7 billion years old, and that might lead you to think that, as nothing travels faster than the speed if light, 13.7 billion light years across must be its maximum size, there are two points that you might not realise

(a) space expands and has been doing for all those 13.7 billion years

(b) objects recede in all directions at once, so even without the effect of (a), 13.7 billion light years in one direction and 13.7 billion light years in the other direction from the point where the Big Bang occurred, must be feasible so that a diameter of 27.4 billion light years across must be feasible and it argues the universe's boundary will be spherical.

Recent calculations suggest that that sphere has a radius of 78 billion light years and that therefore the universe is 156 billion light years from side to side.

This would make the volume, of the known universe, equal to 1.9 × 10^33 cubic light years (assuming this region is perfectly spherical). As of 2006, the observable universe is thought to contain about 7 × 10^22 stars, organized in about 100 billion (10^11) galaxies, which themselves form clusters and superclusters.

26 Answerers before me. Am I the only one who tried to look it up and find out?

Answer 2

There is an edge to what we are able to see and could ever possibly see in the universe. Light travels at 300,000 kilometers per second. That's top speed in this universe—nothing can go faster—but it's relatively slow compared to the distances to be traveled. The nearest big galaxy to our Milky Way, the Andromeda galaxy, is two million light-years away. The most distant galaxies we can now see are 10 or 12 billion light-years away. We could never see a galaxy that is farther away in light travel time than the universe is old—an estimated 14 billion or so years. Thus, we are surrounded by a "horizon" that we cannot look beyond—a horizon set by the distance that light can travel over the age of the universe.

Answer 3

To quote the late great Douglas Adams:

"The Universe is Big. Really big. It may seem like a long way to the corner chemist, but compared to the Universe, that's peanuts."

Answer 4

The observable universe is 78 billion light years in radius, outwards from the point where the Big Bang took place,

Answer 5

The universe is not infinite.... The theory is that the universe is infinitely expanding. If indeed it is expanding, this would indicate that it has boundaries. Otherwise, what is expanding into what? Ipso facto, any object with boundaries has a size, and if it has a size it cannot be classed as infinite. My guess on the radius of the Universe is 13.7 billion light-years and that it is 27.4 billion light-years wide .

Answer 6

If we believe that the universe is expanding (which in itself has yet to be proven) than the universe must be a certain size for it to get bigger, but how big is anybody guess.

Answer 7

The empty bits aren't very interesting but there are estimated to be 70 sextillion (7 x 10^22) stars in it so that is a whole lot of possible places for life to have developed (in the planetary systems around them), Pity they are so far away,

Big enough to be teeming with possibilities, Too big to bring many of them to fruition.

Answer 8

It is not known how large it is. it is either infinite or else very very large. The observed flatness indicates it must be at least 150 billion light years across. The part we can see is about 13 to 14 billion light years in radius, but of course it must be far far larger than that. If I were to make a slightly educated guess I would say infinite but no one really knows.

Answer 9

I'd guess infinite as what would be at the edge of the Universe? A sign saying "under construction do not enter"?

Answer 10

its size is unknown, but it is pretty big, and expanding, like ballon. it may expand forever at an increasing, decreasing or steady rate, or it could reach a point where it keeps a steady size, or start to shrink. it is important 2 understand that although the space in the universe expands the objects in it do not they only become further apart.