The Center Of The Universe

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NASA's Spitzer Science Center: "Ask An Astronomer (Part 1) The Center Of The Universe".

In this popular video series, real astronomers answer common questions about astronomy. Part 1: "Where Is the Center of the Universe?" Dr. Varoujan Gorjian explains the mind-boggling expansion of the Universe.

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Where is the center of the Universe?

This may seem like a simple question. Since the Universe is expanding, it would seem logical that it was expanding away from a particular point. But, the Universe doesn't actually work like that.

The Big Bang, which started the expansion of the Universe, isn't like a firecracker explosion where there is a boom and all the pieces go flying apart from a single point. The Big Bang was in fact the creation of matter and space. And it is this space that's expanding.

Think of space as if it's a sidewalk with people standing on it. The expansion of the Universe isn't the people walking away from each other, but it's more like the sidewalk is spreading and moving the people apart.

As a simpler example, let's take the surface of a balloon. We can draw galaxies on it, but notice that no galaxy is at the center of the surface. When we blow up the balloon, all the galaxies spread apart from each other.

If you look at any single galaxy, all the other galaxies seem to be spreading away from it. Every galaxy sees itself as the center of the expansion. But since not every point can be the center, that really means there is no center.

The more space there is between any two galaxies, the more the expansion will be pushing those galaxies apart. So the further away one galaxy is from another, the faster it will be expanding away from it.

This discovery was made in 1929 by Edwin Hubble, who discovered that further away a galaxy is, the faster it was receding from us. And that's now known as The Hubble Law. The rate of expansion of the Universe is now known as The Hubble Constant.

So, even though it looks like we're at the center of the Universe, the Universe doesn't actually have a center.

• http://spitzer.caltech.edu/video-audio

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The Spitzer Space Telescope is a NASA mission managed by the Jet Propulsion Laboratory (JPL)
• http://www.jpl.nasa.gov/
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Category:

Science & Technology

Tags:

• center
• universe
• nasa
• spitzer
• hubble
• space
• telescopes
• astronomers
• astronomy
• expansion
• big
• bang
• explosion
• science
• creation
• matter
• milky
• way
• galaxies
• redshift
• law
• constant
• jpl
• caltech

[TheMaximumoverload]

I think humanity barely grasps what the universe for what it is because new theories are being explored every day. What if the universe is expanding and shrinking all at the same time? Think about it. From are perspective it is expanding, but from another point of space time it could be shrinking. We only see it as expanding because time is moving forward for us. They say infinite small is infinite mass. Maybe the universe works the same way. Just a thought!

[ttwilkable]

This is a great video

[grisgrisy]

Very enjoyable thank you

[staranjela]

brilliant video

[QuantumDisciple7]

@yvladyslavo Yea... I'm not sure what I was getting at there. I mean, there are some proposed designs of the shape of the universe that would prevent you from seeing yourself if you looked far enough. It is kind of like a perpetual space-time loop that feeds itself with renewed space-time. I'm not sure on what I believe. I just know we can't see past the Cosmic background, so there must have been some point of creation/barrier that prevents light or information from traveling beyond it.

[yvladyslavo]

@QuantumDisciple7 ok, thanks man. though regarding you last sentence, it is still unclear to me - if it IS like a huge 3D pacman, what meaning the shape concept has in that case - anywhere you go, anywhere you look (theoretically...) the same infinitely repeating stuff.

[QuantumDisciple7]

@yvladyslavo It actually is like a pacman, only in three dimensions. The reason that we couldn't "theoretically" see the backside of ourselves by shining a beam of light in one direction of space is due to the actual curvature of space-time itself and the unknown shape of the universe.

[QuantumDisciple7]

@yvladyslavo I agree with you about the shape having a center; however, the center in this case is not in the three spatial dimensions we live in. All we know is the three dimensional surface of the balloon. The center inside of the balloon is not in the medium in which we live.

[yvladyslavo]

i still don't get it. this would be true only if we assume that the universe is infinite, or that it's like a pacman (that when you come to the edge you find your self at the "beginning" of the other one).

any shape has a centre and has an edge, even if it's expanding uniformly.