How big is the universe?

The universe is about 13.7 billion years old. Light reaching us from the earliest known galaxies has been travelling, therefore, for more than 13 billion years. So one might assume that the radius of the universe is 13.7 billion light-years and that the whole shebang is double that, or 27.4 billion light-years wide.

But the universe has been expanding ever since the beginning of time, when theorists believe it all sprang forth from an infinitely dense point in a Big Bang.

“All the distance covered by the light in the early universe gets increased by the expansion of the universe,” explains Neil Cornish, an astrophysicist at Montana State University. “Think of it like compound interest.”

Need a visual? Imagine the universe just a million years after it was born, Cornish suggests. A batch of light travels for a year, covering one light-year. “At that time, the universe was about 1,0 times smaller than it is today,” he said. “Thus, that one light-year has now stretched to become 1,0 light-years.”

All the pieces add up to 78 billion-light-years. The light has not traveled that far, but “the starting point of a photon reaching us today after travelling for 13.7 billion years is now 78 billion light-years away,” Cornish said. That would be the radius of the universe, and twice that — 156 billion light-years — is the diameter. That’s based on a view going 90 percent of the way back in time, so it might be slightly larger.

Source(s): http://www.space.com/scienceastronomy/mystery_mond…

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Source(s): Natural Penis Enlargement Exercises : http://biggerpenis.raiwi.com/?fMkb

1) We know that the universe is at least as big as what we see (visible universe has a radius of 13.7 billion light-years). The universe could have been wrapped onto itself so that it appears big while being small. A bit like Earth’s surface that goes on forever if you travel around, but we know that you simply keep going over the same route after every turn.

A probe was sent out (called WMAP) to look specifically for clues of this, and did not find the clues. Therefore, the universe is at least bigger than 27.4 billion light-years in diameter.

2) When we look far away, we also look towards the past. Because the universe is expanding, the past universe was smaller than it is now. When the distances are corrected for the effect of the (relatively) slow speed of light, we find that the universe must be at least close to 1 billion light-years in diameter (this is called the “co-moving” distance: the distance if we could see where things are now, instead of back then).

3) It appears that the universe is boundless (meaning, it has no end, no edge). This, by itself, does not mean that it is infinite. However, it might mean that the universe could be curved onto itself. A bit like the surface of Earth, which goes on forever in all directions (no end, no edge) even though we know that the Earth’s surface is not infinite.

However, if the universe is curved onto itself, then there must be other dimensions in which the universe is a finite object. Earth’s surface goes on forever if you consider it a 2-dimension surface. However, when you look at Earth in 3-dimensions, it is obviously a finite sphere (and a tiny one within the universe).

4) If the universe has curvature then this curvature should be measurable if we had precise enough instruments.

Earth’s surface is curved. If you draw a triangle on Earth’s surface, the sum of the inside angles will be more than 180 degrees. A triangle in plane geometry has a sum of exactly 180. The difference is called the “spherical excess” and it is directly related to the spherical triangle’s area relative to the size of the sphere.

Let’s take an extreme example: Start from the North pole (call this point A). Go south keeping to a straight line (along a meridian) until you reach the equator at point B. You now have a side AB. Turn right (to the West) exactly 90 degrees and go West in a straight line (along the equator). You will have made a 90 degree angle at B.

Continue until you have gone the same distance as AB. You are now at point C, which has a difference of 90 degrees in longitude from point B. You have just completed side BC.

Turn right again exactly 90 degrees. You are now facing due North. If you go in a straight line (following a meridian) you will stumble upon point A, having completed the side CA.

Because the difference in longitude from B to C is 90 degrees, the angle at A must also be 90 degrees.

You will have drawn a triangle ABC with three 90-degree angles. Sum of angles = 270. Spherical excess = 270 – 180 = 90

The same thing happens for 3-dimensional volumes that are within a curved sub-space (except that we must use “solid angles” measured in a unit called “steradian” — but the idea is the same). Every time we try to measure the “curvature excess” in the sum of solid angles, we get zero. This makes it look like the universe is flat, not curved.

But, it could very well be that our instruments are not precise enough (yet).

5) It is possible for the universe to still be curved onto itself and still be exactly “flat” in the geometrical sense (with the sum of angles and stuff like that). However, this would means that the shape is not a simple one (for example, it cannot be the 4-dimension equivalent of a sphere).

Imagining the universe as one of those shapes makes it a lot more complicated to explain what we observe. This does not mean that it is impossible. But until we get more information, we should continue with the simpler idea that the universe is really flat. This principle is called “Occam’s Razor”.

6) If the universe is really flat AND if the universe really has no bounds, then it must be infinite.

An infinite universe does solve a lot of problems: for example, no need to explain what the universe expands into, since it expands into itself.

The universe is constantly expanding, as it is currently thought to have began from a single explosion called, the “big bang.”

The universe will continue to expand until the force from the explosion will reach a point where it won’t be able to compete with the universes gravity from the mass in the universe, and thus it will start to contract, and the universe will shrink.

Steven Hawking actually wrote a book called “The universe in a Nutshell” which talks about the expansion of the universe in quite a lot of depth. He mentions all of the above in it as well.

Currently they cannot predict exactly when the force of expansion will reach 0 as gravity pulls at the outer edge of the universe, but it is predicted to be billions of years from now.

As for how “big” the universe is currently, we cannot be exactly sure, because light only travels so fast, and we can only see as far as the light reaches, but they’ve worked out formulas to give approximations to how large the universe is. Let’s just say that the universe is currently so large that any number would still not give you a fathomable picture of how grand it is. It really is monstrously huge, and expanding constantly.

Hope this helps answer your question.

Source(s): Steven Hawking’s book “The Universe in a Nutshell”

There is really no point, right at this moment, guessing the size of the observable universe, whether it is 27, 50 or 1 billion light years across.

No human being or most powerful instrument has managed to determine the boundaries of our universe or as some believe, those of the outer universes, as there is a possibility of a system of multi-verses.

The present thinking is that the Universe or Multi-verses are infinite and as there is not likely to be a solid ‘wall’ at the boundary or boundaries, there is then no way for the impossible or unimaginable distances to be measured by any means.

I truly believe that the size of our Universe is going to remain as one of the 3 greatest of all mysteries(the others being Time-travelling and 5th – 10th Dimensional Worlds), and shall never get solved by any human, technological or godly intelligences. It would be wiser and more practical, instead, to direct all our efforts, energies and resources during our short life-spans to try to solve other easier mysteries that can benefit humans. Just to be more realistic, keep reasonably sane, and avoid getting totally lost in the vastness of space. :-)))

Someone almost had it right. They said the observable universe was about 157 billion light years. That is incorrect. The observable universe is about 27 light years in diameter. The universe has only been around for 13.5 billion years so we can only see anything within that radius.

The universe (the whole umiverse) is about 157 billion light years. This is based on the measured dispersion of the cosmic background radiation. The reason for the difference is that the universe, very early in its history, went through an inflationary period where it expanded exponentially.

the Universe is currently still expanding, an effect of the Big Bang.

but you should know that most of space is an absolute void, so far away from anything that not even the light of distant stars can be seen. gravity is not even present there–there are no objects.

eventually, the Universe will stop expanding, and stars will stop being produced. That is, the Universe will inevitably die. Of course, that is so far into the future that humans will never have to worry about it. Not only will Earth be gone long long ago, but humans, granted they survive, will have evolved into totally new creatures. for example, Neanderthal to Homo Sapiens.

I’M NOT RIGHTLY SURE HOW BIG IT IS, BUT HERE IS A COUPLE OF FACTS TO CONTEMPLATE.

Go to the NASA site and click on hubble images and find the one that has a cluster of galaxies.

Now think about this as you look at the picture. Each galaxy is said to contain in the neighborhood of 1 billion stars. We are 4 light years from the nearest star in our galaxy. That would be 4X186,0 miles a second, for however many seconds there are in 4 year. Your calculator can’t even calculate it.

each galaxy has that many stars, 1 million to a billion. and the space in between. It is so far beyond our comprehension we can’t even begin to think that big.

Look at this period . Now pretend that is the sun, a star. Now get a basketball or beachball is even better. Ask your self how many of those periods would fit inside that ball? That would be just a portion of the matter we know about, all those periods.

One of my favorite lines from a movie is the movie contact. She asks her dad if there is other life out there. He answered something like, if there was no other life it would be a terrible waste of space. So true, so true.

Source(s): me, NASA,HUBBLE

The Earth is largely on the midsection of the OBSERVABLE Universe. Why? because of the fact we are staring at stuff on earth, and the cost of sunshine limits what we see by skill of the comparable volume at any perspective we glance out from. interior the entire universe, we are only a speck of sand on a sea coast the size of… some thing vast. we are no longer time-honored, because of the fact the Earth has no longer something specific approximately it forces-smart to make it targeted. the place the truthfully centre of the universe is… we’d ought to understand the size of the entire factor, and the form of it – will possibly no longer be a plenisphere.

“All the distance covered by the light in the early universe gets increased by the expansion of the universe,” explains Neil Cornish, an astrophysicist at Montana State University. “Think of it like compound interest.”

Need a visual? Imagine the universe just a million years after it was born, Cornish suggests. A batch of light travels for a year, covering one light-year. “At that time, the universe was about 1,0 times smaller than it is today,” he said. “Thus, that one light-year has now stretched to become 1,0 light-years.”

All the pieces add up to 78 billion-light-year