Universe is 156 billion LY across

[Realitycheck]

That's what it says here. This is kind of old news, 2004. Interestingly, they don't mention anything about superfast inflation, just the aggregate growth exceeding light speed. Then again, this is 2004. I checked out the WMAP website, and while it did not confirm this conclusion, it did offer another good resource for explaining everything related to expansion.

 

 

http://www.space.com/scienceastronomy/mystery_monday_040524.html

 

http://map.gsfc.nasa.gov/

[doG]

More accurately the article states, "The universe is at least 156 billion light-years wide."

 

For me it says nothing about what may or may not lie beyond that boundary.

[jackson33]

Think that figure 156, is calculated on the principle light (energy) has traveled at different speeds, when the universe was smaller. If we see light from 13.7 LY away, then what created that light was has increased via expansions in higher numbers. 186kmps just what it is today. Something like that...

 

Doesn't BBT, suggest where ever the universe is expanding from, nothingness is what its expanding into. No space, no time, just nothing.

[Realitycheck]

I don't see any reason why the speed of light would change over the course of time. If you take the growth rate over the span of a small section of the universe, say 1 light year across growing at a rate of .000000001 LY per year (or 5,875 miles per year), then multiply that by the total size, 156 bLY, then the whole universe is essentially growing at 156 LY per year. This way, it adds up. Of course, these are not intended to be the actual numbers and does not even factor in inflation, it is just an example for demonstration.

[Riogho]

Now take 156 and divide it into 1.1368613138688

 

And what do we get...

 

1/137

 

*gasps*

 

The evil!

[Martin]

More accurately the article states, "The universe is at least 156 billion light-years wide."

 

...

 

That's right.

 

I started a thread about this back in May 2004, when the news item came out that the OP cites.

 

http://www.scienceforums.net/forum/showthread.php?t=4268

 

In today's context I don't think it is a very important result. It is just an at least and we now have estimates that are larger than that. However Neil Cornish, the astronomer who gave the figure of at least 156 billion lightyears, at that time had a nice picture of his pet monkey----on his home page.

That added a bit of interest to an otherwise kind of ho-hum.

 

Regret to say he has changed his homepage and the photo doesn't show the monkey any more.

 

A 'best fit' estimate of the size of the universe as of January 2007 (when Ned Wright published) would be that either it is infinite spatial extent, or if it is finite then circumference would be an estimated 820 billion LY.

 

Cornish's paper (and the result mentioned in the OP) don't represent a boundary. they are just an at least estimate which has been surpassed.

There are no indications, in any cosmology research to date, of a physical boundary to space. So the idea of "diameter" is misleading. What Cornish actually said was "topology scale" but appears to have told the journalist "you can think of it as a diameter". I wouldn't advise that.

Better to think of the length of the longest geodesic (i.e. circumference) or half that length, IMO.

[Realitycheck]

Infinite does not compute.

[jackson33]

I don't see any reason why the speed of light would change over the course of time. If you take the growth rate over the span of a small section of the universe, say 1 light year across growing at a rate of .000000001 LY per year (or 5,875 miles per year), then multiply that by the total size, 156 bLY, then the whole universe is essentially growing at 156 LY per year. This way, it adds up. Of course, these are not intended to be the actual numbers and does not even factor in inflation, it is just an example for demonstration.

 

Actually I don't either, but then I have trouble with most of BBT.

 

It is covered in your article 'space.com' stretching reality. Its a quote think the author is mocking. Light we receive from the known universe, is said to be constant C in all cases.

 

When arguing BBT, I use the surface of what should be the shell, of what expansion should now be....Sphere surface= 4 x 3.14 (p) x RSq. (Radius squared)...It does double quite often, but why would the mass of anything be different or the speed of light. A billion pound object would then, would still weight a billion pounds now or a 100 billion years in the future, but would appear smaller. Think some one has figured energy waves would be likewise effected. This is speculation on my part, since IMO, everything is pretty much the way it was 50 billion years ago or much, much longer...

 

If your interested, I would also think, Andromeda, a Spiral Galaxy a couple million light years out there would never make it projected collision with our Milky Way in 5 billion years or so, because the total volume of space now between, will have more than doubled by then....if BB is correct.

[Realitycheck]

In the space.com article, they talk about how the soccer ball shape won't work but don't really expound about why. The way I see it, the universe wouldn't expand uniformly in all directions because it is not so evenly distributed, but bound by clumps of matter holding things together. After 13 billion years, things have had lots of time to sort themselves out into groups. A lone galaxy might be zooming out at the cutting edge, whereas areas more densely populated would probably tend to hold each other together more tightly. Therefore, the universe would probably be shaped more like a very irregular sea urchin than anything.

 

The same goes for Andromeda and the Local Group. If you think about it, it is rather unlikely in the scenario that you depicted that two galaxies would collide. However, we see it happening elsewhere, and it is because gravity has kept them within close proximity all this time. Where maybe the space between the local group has not grown so much because of the gravitational effect, but the space between the local group and the rest of the universe continues to grow.

[Farsight]

Martin can you give a link to the ned Wright paper? I can't find any mention of it it either on arxiv or on http://www.astro.ucla.edu/~wright/cosmolog.htm

[Martin]

Martin can you give a link to the ned Wright paper? I can't find any mention of it it either on arxiv or on http://www.astro.ucla.edu/~wright/cosmolog.htm

 

Farsight, thanks for asking.

http://arxiv.org/abs/astro-ph/0701584

The reason you didn't find it on arxiv is probably that you didn't search for author E Wright

Ned is a nickname for Edward.

 

I hope you find the paper interesting! If you have questions about it, ask.

 

You can see from the title that he is drawing on several different sets of data:

Constraints on Dark Energy from Supernovae, Gamma Ray Bursts, Acoustic Oscillations, Nucleosynthesis and Large Scale Structure and the Hubble constant

 

 

If you scroll down to page 17 of the PDF you will see Table 4

where it gives a figure of Omega_k = - 0.011

this is equivalent to saying Omega_total = 1.011

 

(this is what translates into a circumference of 820 billion LY)

 

and right under the table you will see:

 

"...of the need for dark energy, and a much better constraint on the curvature of the Universe. Using all the data together gives the plot shown in Figure 6. The best fit model is slightly closed with Omega_tot = 1.011 and Omega_M = 0.315. The best fit flat LCDM model has less than one more unit of χ2 than the best fit non-flat LCDM model so there is no evidence for spatial curvature from these fits..."

 

what he is saying is that the fit is better with curved and closed than it is with flat and infinite BUT it is not ENOUGH better to be called statistically significant---namely curved closed is around one unit of chi-square better, and that is not enough better to be convincing.

 

On the other hand the data doesn't favor flat infinite either. I'd say it is balanced on the fence, with a slight tilt towards curved-closed space.

(with no big crunch of course, the closure is spatial only.)

[Cmac22]

A billion pound object would then, would still weight a billion pounds now or a 100 billion years in the future, but would appear smaller.

 

Not that it matters much but were you trying to say an object with a mass of a billion grams (or whatever)? because isnt weight a force affected by gravity and mass. so, after 100 billion years the gravity pulling the object would be much weaker because of expansion, and so the weight would decrease. just like our weight on the moon is different than weight on earth.

[jackson33]

Not that it matters much but were you trying to say an object with a mass of a billion grams (or whatever)? because isnt weight a force affected by gravity and mass. so, after 100 billion years the gravity pulling the object would be much weaker because of expansion, and so the weight would decrease. just like our weight on the moon is different than weight on earth.

 

Not really; If you take a one inch round patch and place it central on a 10x10 inch picture frame, you get a visual concept of size. Take the same patch and place it on a 10x10 foot frame it would appear much smaller. When we observe the universe as was, say in images 5 billion years ago, there is no indication anything is proportionately different, yet the volume with in the BBT universe has certainly doubled.

 

I have trouble accepting Big Bang, this just one small issue. Think your explaining Newtonian Gravity opposed to Einstein Space-Time Fabric, but under either, effects would not change, IMO...