What is the Size of the Universe?

When I first made the Hubble Deep Field: The Most Important Image Ever Taken video, there has been a consistent avalanche of comments stating that there is no way the universe can be this large. Figuring out the size of the universe isn't as simple as just multiplying the distance light travels in one year by the age of the universe.

We need to account for the expansion.

Astronomers have recently estimated a lower limit to the size of the universe to be roughly 78 billion light years in diameter. In this video I try to explain how that's possible.

For the more technically inclined, here's a link to the scientific paper this vid is based on:
http://arxiv.org/abs/astro-ph/0310233

All music used:

Leonard J. Paul - The Corporation Soundtrack:
http://www.archive.org/details/kpu101

iambic2 - under these stars, we'll sleep again:
http://www.archive.org/details/laridae031

Kevin MacLeod - Truth of the Legend
http://incompetech.com/m/c/royalty-free/index.html?keywords=choir&Search=...

Category:

Science & Technology

Tags:

• size of universe
• universe
• cosmology
• hubble deep field
• most important image
• expansion of the universe

[McSmooth5150]

@mknomad5

no no the big bang surely happened 13.7 billion years ago, we know this because that is our horizon or are field of view. When we reach the end of that field of view we see the beginning of the universe because we are looking further back in time. If you research WMAP you will then believe the universe is that age! The reason the universe is 78-79 Billion light years across is because they are adding the expansion rate (dark energy) which is a fixed rate everywhere in the universe.

[JheakrynaKyAlur]

what has the fact of being christian, muslim, pink or yellow, have to with the fact that the universe is as it is? ;D

[jkang24]

We just may be in the best part of the Universe... Mother Earth

[sniped101]

@McSmooth5150 how do we know the age of the universe?

[McSmooth5150]

@sniped101 it apears you have some basic facts mixed up. No worries though if you just read say, a brief history of time or fabric of the cosmos you will see that we know for certain the age of the universe but we believe that the size of the universe is infinite. We are talking here about the size of our cosmic horizon not the size of the entire universe, which is easy to mix up. One of the most basic yet not understood subject is size length of our cosmic horizon. Good luck on your studies!

[sniped101]

@McSmooth5150 and you would be wrong because you only have the information of what you can see. You can't see what was seen 13 billion years before you were born because the universe is expanding everything faster than the speed of light. This is why i believe the universe is much older than we could ever imagine.. Because we can only SEE back to 13.7 billion years... at 13.71 billion years, we dont know because we cant se

[sniped101]

@McSmooth5150 but if the observable universe is 13.7 billion years ago, How do we find out how big the ACTUAL universe is? Answer? We can't because we can't see anything past 13.7 billion years because it fades away. This is why if you were a scientist in the future on a distant galaxy born 13 billion years from now, you would only see your galaxy and you would stare at an empty universe, thinking you were the only thing.

[Lennyoracle]

@tdarnell When referring to the expansion of the universe you keep implying that new spacetime is created "in between" objects in space, resulting in their growing relative distances. Is this just to help illustrate a point? Because in your road analogy you imply the stretching of the existing road (taken: the expansion of existing spacetime). Which do you believe?

[maxzamoraj]

So, they universe expands the same as Minecraft?? It creates more space as you travel? Wow, the secrets of the universe... Y U HAZ 2 B SO COMPLEX!!!!?

[GYROMIGHT1]

@ScrubifyHD I think everyone knows there are multiple universes...

[FordPrefect23]

@McSmooth5150 I can't help but feel you're wasting your time, you may well be the one trying to play chess with a pigeon as the old analogy goes. You get what you're saying, I do, anyone who'd educated does, but blind faith leads to further blindness in order to protect that faith from reality. There is little point in trying to convince much of the opposing camp because they refuse to listen to the science, you have to wait for them to catch on in their own time.

[adamdyerseve]

the speed of light is 300,000 km per second (not 300,000 meters per second as suggested in the clip)!