New study super-sizes the universe

[Natoma]

http://msnbc.msn.com/id/5051818/

Interesting article.

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 (which is the equivalent of about 5.9 trillion miles or 9.5 trillion kilometers). "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.)

 

[jvd]

I guess this is the universe's counter attack to mc donalds getting rid of its supersized meals . Its the universe say you fat bastards!!!! I gotta get fatter too or you wont fit in me soon !!! Go on a friggen diet !!!

 

[Natoma]

 

[Hafnu]

The universe just grew. Again.

 

[Tahir2]

Is this a 'new' theory?

 

[max_cool]

something to think about is that since a photon has no mass, can we really accept it as expanding the universe. Obviously the galaxies of the universe are not traveling at the speed of light, the only thing's that are, are photons and gravitrons niether of which has mass. So I ask, can you accept a particle that has no mass as the edge of the universe??

I know the above is BS but it popped into my head and I wanted to share.

 

[Sabastian]

Is this a 'new' theory?

No I read that in some book on cosmology years ago now. But it is interesting for people who didn't quite realize it that when they look up to the stars they are looking back in time.

 

[London Geezer]

Is this a 'new' theory?

No I read that in some book on cosmology years ago now. But it is interesting for people who didn't quite realize it that when they look up to the stars they are looking back in time.

What's even more mind boggling is that every time i try to explain the same to other people, it takes me a whole 10 mintues. They just don't get it. I mean, thankfully that is one of the easy things to understand about the universe...

 

[g__day]

As far as I knew - up to a few days ago and this is in my field of interest - the diameter was best calculated as 40 billion light years - and this figure accounts for both inflation and the unfolding of spacetime!

I didn't follow how they derived their assumed expansion coefficient in "the starting point of a photon reaching us today after travelling for 13.7 billion years is now 78 billion light-years away". Ask why has distance itself expanded by exactly 78/13.7 - what creates the 78 - not 40 or 39 or 2,000? To me that is just an unexplained magic number. The last magic number I saw for that figure was 40 - why is it now 78?

 

[London Geezer]

48. it's always 48.

 

[Mendel]

A magical word "hubble constant" somehow popped into my mind but then my head started to hurt.

 

[London Geezer]

*raises hand*

... head started hurting at "interesting..." in the first post by Natoma.

 

[Sabastian]

*raises hand*

... head started hurting at "interesting..." in the first post by Natoma.

My head starts hurting most everyday.. starts when I get up in the morning. This is a bizarre experience being alive... bla bla bla . It is amazing really on how massive the universe is and how small we really are.. and how small things get! Me and my microscopic keyboard.. lol. Sometimes I think I am going mad.

 

[Mendel]

anyways I always thought universe was homogenous and isotropic in larger scales. As in infinite diameter. Theory includes Big Bang not happening in any specific place but everywhere. Singularity was *everywhere* . This consept includes something very ankward. Space that is infinitely small, infinitely massive and infinite at the same time. In fact we could just as well consider the expansion of universe irrelevant because in really big scales we have barely grown at all... and think we're still living in singularity and about to go Big Bang. Ok.. I just went nuts out of the window. Back to work.

 

[evil]

48. it's always 48.

42, I'm sure.


And anyway who says that light travelled at the same speed 13.7b years ago? Perhaps it didn't!

 

[London Geezer]

48. it's always 48.

42, I'm sure.


And anyway who says that light travelled at the same speed 13.7b years ago? Perhaps it didn't!

How said light was the same 13.7BN years ago...?

 

[nutball]

And anyway who says that light travelled at the same speed 13.7b years ago? Perhaps it didn't!

There are some theories that have put forward that postulate that too (VSOL, Variable Speed-Of-Light). Yet more mathematical parlour games.