How so large is the universe ?

Answer 1

If you've ever wondered how big the universe is, you're not alone. Astronomers have long pondered this, too, and they've had a hard time figuring it out. Now an estimate has been made, and its a whopper.

The universe is at least 156 billion light-years wide.

In the new study, researchers examined primordial radiation imprinted on the cosmos. Among their conclusions is that it is less likely that there is some crazy cosmic "hall of mirrors" that would cause one object to be visible in two locations. And they've ruled out the idea that we could peer deep into space and time and see our own planet in its youth.

First, let's see why the size is a number you've never heard of before.

Stretching reality

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 1,000 times smaller than it is today," he said. "Thus, that one light-year has now stretched to become 1,000 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.

"It can be thought of as a spherical diameter is the usual sense," Cornish added comfortingly.

(You might have heard the universe is almost surely flat, not spherical. The flatness refers to its geometry being "normal," like what is taught in school; two parallel lines can never cross.)

Answer 2

The present distance to the edge of the observable universe is estimated to be about 78 billion light years.

However, the (believed to be) finite universe has been shown to be constantly expanding, and was proved by Albert Einstein according to the General Theory of Relativity and later corroborated by other scientists such as Hubble. If you want to do more reading about the Theory of Relativity, go here:
http://www.bartleby.com/173/

In addition, many people theorize that the universe is infinitely linked, and it could be argued that since the universe is continually expanding it is technically infinite. However, this can be disproved by measuring the average density of matter and energy throughout the universe (which is not possible at the moment). Depending on this density the universe will either expand infinitely or eventually crash back in to itself.

Hope this helps, and thanks for the question, I learned something too!

Answer 3

What a wonderful question.
The universe we live in is believed to be very, very, very... etc. big. No matter who you ask, no one can surely agree, but i doubt anyone can disagree with the writers of Monty Python...

Just remember that you're standing on a planet that's evolving
And revolving at nine hundred miles an hour,
That's orbiting at nineteen miles a second, so it's reckoned,
A sun that is the source of all our power.
The sun and you and me and all the stars that we can see
Are moving at a million miles a day
In an outer spiral arm, at forty thousand miles an hour,
Of the galaxy we call the 'Milky Way'.
Our galaxy itself contains a hundred billion stars.
It's a hundred thousand light years side to side.
It bulges in the middle, sixteen thousand light years thick,
But out by us, it's just three thousand light years wide.
We're thirty thousand light years from galactic central point.
We go 'round every two hundred million years,
And our galaxy is only one of millions of billions
In this amazing and expanding universe.The universe itself keeps on expanding and expanding
In all of the directions it can whizz
As fast as it can go, at the speed of light, you know,
Twelve million miles a minute, and that's the fastest speed there is.
So remember, when you're feeling very small and insecure,
How amazingly unlikely is your birth,
And pray that there's intelligent life somewhere up in space,
'Cause there's bugger all down here on Earth.

Now, how many cubic lightyears big is the universe?

Answer 4

The size of the universe cannot be described by a word as it is infinite.

Answer 5

keep on going for the rest of your life you will never reach the edge. Take your decendants too they will never reach the edge

Answer 6

logic tells me it is most likely very big. I also heard somewhere that it is increasing in size exponentially.

Answer 7

infinite - 1 km

Answer 8

more then anybody can imagine.Its just beyond everyones imagination n wit.So if u think its infinite , its not... its actually beyond infinity.

Answer 9

imagine. light takes years to cross it

Answer 10

Big. Very big.