Most distant object ever seen

Redshift (Phil) · #1 04-11-2009, 11:40 PM

The afterglow of an exploding star is said to be 13.1 billion light years from earth. It exploded some 630 million years after the big bang. The article says the light has taken 13.1 billion years to reach earth.

http://www.newscientist.com/article/...e-spotted.html

This confuses me somewhat. It seems logical to me that 630 mil years after the big bang the universe would have been much smaller than it is today. So the light from that exploding star would have reached the earth (actually the earth wasn't around then, so by that I mean our point of reference in the young universe) in no more than 630 million years.

I would have thought that every point in the universe would have been much closer at that time and it has taken 13.whatever billion years to expand to the size it is now in a gradual way. So if that is the case then there is no "looking back" in time because the light from the early universe has already passed us by long long ago.

Enchilada · #2 05-11-2009, 03:09 AM

Quote:

Originally Posted by Redshift

It exploded some 630 million years after the big band.

Which band was that? Benny Goodman or Glen Miller??

(This has got to make "Here and There" in the Royal Astronomical Society in London, journal "The Observatory."! Pity it is only in published material.
Note:The classic one is this; http://adsabs.harvard.edu/full/1952Obs....72R..88.)

Thanks for correcting the error. Don't worry, I've made worst clangers than that!

Paddy (Patrick) · #3 05-11-2009, 02:55 PM

Quote:

Originally Posted by Redshift

This confuses me somewhat. It seems logical to me that 630 mil years after the big bang the universe would have been much smaller than it is today. So the light from that exploding star would have reached the earth (actually the earth wasn't around then, so by that I mean our point of reference in the young universe) in no more than 630 million years.

I would have thought that every point in the universe would have been much closer at that time and it has taken 13.whatever billion years to expand to the size it is now in a gradual way. So if that is the case then there is no "looking back" in time because the light from the early universe has already passed us by long long ago.

I'm not much of an expert in cosmology, but perhaps this is the result of inflation. Shortly after the big bang, the universe expanded very rapidly, faster than light speed so light from close objects still took a long time to arrive as space itself was expanding. Secondly, off my head I've no idea about how big the universe was at 630 myo, but I think it would have been very large even at that tender age.

I reckon you will get better answers from those around that actually know what they're talking about.

Redshift (Phil) · #4 06-11-2009, 02:29 PM

Patrick. Good point you make about the rate of inflation. That could be the answer. Thanks.

renormalised (Carl) · #5 06-11-2009, 03:02 PM

This should clear it up for you, but if you have any questions, just ask

Distance, Time and the Expansion of the Universe

AdrianF (Adrian) · #6 09-11-2009, 09:06 AM

I have a question for the experts

If at the beginning the universe was expanding at faster than the speed of light and an event eg a supernova happened and the light radiated at the speed of light wouldn't the light from the supernova appear to stand still until the expansion slowed to less than the speed of light?
Or is it a relative thing?

Adrian

renormalised (Carl) · #7 09-11-2009, 01:51 PM

Quote:

Originally Posted by AdrianF

I have a question for the experts

If at the beginning the universe was expanding at faster than the speed of light and an event eg a supernova happened and the light radiated at the speed of light wouldn't the light from the supernova appear to stand still until the expansion slowed to less than the speed of light?
Or is it a relative thing?

Adrian

I'd answer your question, but right now, my brain feels like mush (just finished an exam), so hopefully Steven (sjastro) or someone else with a fresh mind can answer it soon...however, it is a relative thing (the answer)

sjastro · #8 09-11-2009, 02:57 PM

You will never see the light from the event as it is not only beyond the observable horizon of the Universe, but the rate of expansion of the Universe is also increasing.

Steven

xelasnave · #9 13-11-2009, 11:58 PM

If our Universe is finite ..and given that the BB theory starts with a point such that an infinite Universe is eliminated via that theory (we can not double anything into infinite etc).. so we must accept a finite Universe if we subscibe to the posibility that the BB theory is valid...so may I ask into what medium does our finite Universe expand into?....

OR if our Universe is say 160 billion light years "wide" and expanding to a greater "size" what "space" does it expand into or into what "space" does this alledged expansion intrude???

I use the measure of 160 billion light years simply because that is the highest number I have read as being the outter limit for the Universe.... but whatever size we set upon finally the question presents to me ...into what do we expand???
AND if we are expanding then is would seem reasonable that such a statement contemplates that the expansion must be in relation to "somerthing" so what is the something that offers a measure to observe such is so?

alex

Redshift (Phil) · #10 14-11-2009, 08:51 AM

The experts in cosmology suggest that the big bang theory is the best model we have at the moment. It is backed up by observations such as the redshift in the light displayed by stars that are moving away from us.

So if the big bang originated from a singular point then surely there must still be a point that could be referenced as the centre of the universe and an outer frontier boundary.

What is the universe expanding into? Maybe it is just an infinite empty space that lies beyond the boundaries of our universe.

Personally, the idea of infinity messes with my head. It is just too hard to fathom; but what else can it be?

xelasnave · #11 14-11-2009, 09:16 AM

Infinity, "empty" and "nothing" are each very interesting concepts.
Infinity can have a massive part removed but must remain infinite.
No matter how empty something is it will still contain something.
Nothing is an an absence of everything so it cant really be there such that we can comptemplate its existence.
I wonder about such things and as I have said before around the place nothing I feel holds the key to understanding everything.
What I find a worry is if BB if correct, and there is a great deal offerred in support of the theory, what came before...but an alternative of an infinite Universe is impossible to get ones head around.
alex

michaellxv (Michael) · #12 14-11-2009, 09:32 AM

Quote:

Originally Posted by Redshift

So if the big bang originated from a singular point then surely there must still be a point that could be referenced as the centre of the universe and an outer frontier boundary.

The best visual explanation for the expansion of the universe is that of an expanding baloon. Draw some galaxies on one and blow it up. Everything moves away from everything else, but no point on the surface of the baloon is at the centre.

Even though the baloon is a 3D object this is still only a 2D model as we are only considering the 2D surface of the baloon.

Transalating this to the 3D physical universe we can see is what does my head in.

Michael

xelasnave · #13 14-11-2009, 09:45 AM

AND we still dont know who or what is blowing up the ballon.
alex

michaellxv (Michael) · #14 14-11-2009, 09:50 AM

I just hope it doesn't pop.

Michael

sjastro · #15 14-11-2009, 10:26 AM

The scale of the Universe is expanding.

Distant galaxies that are not gravitationally bound remain in the same fixed position in space despite the fact that the Universe is expanding.

To state that the Universe is expanding into existing space is meaningless.

Steven

Redshift (Phil) · #16 15-11-2009, 10:03 PM

Given that the study of cosmology is still in it's infancy I don't think we can say that any idea or concept is meaningless. We should always be open to ideas that may help to expand (excuse to pun) our understanding of the universe.

I've recently found a thesis titled "The Evolution of High Redshift Clusters of Galaxies" which focuses on cosmology and structure formation in the universe. I noted with some amusement that the thesis was for the degree of Doctor of Philosophy. Hardly what I would think of as a hard core science degree.
http://www.aao.gov.au/local/www/sce/...is/thesis.html

Anyway, I recon we should always bear in mind that the Big
Bang theory is just that...a theory. Some day someone may come up with a better theory. Maybe it will be an Iceinspace contributor.

Paddy (Patrick) · #17 15-11-2009, 10:29 PM

Sorry to be pedantic, Phil, but most doctorates in any field of science or humanities are called Doctorates of Philosophy (literally love of knowledge) and are not in the subject we call "philosophy". The author is most likely a physics/astronomy post graduate.

sjastro · #18 16-11-2009, 07:42 AM

Quote:

Originally Posted by Redshift

Given that the study of cosmology is still in it's infancy I don't think we can say that any idea or concept is meaningless. We should always be open to ideas that may help to expand (excuse to pun) our understanding of the universe.

An idea or concept which violates the very principles of cosmology is meaningless.

Cosmology is based on a mathematical principle that the scale of the Universe is expanding instead of the Universe expanding into existing space.

If the later occurred we would find the recession velocity is independent of the distance of the observer from the object, in other words each object would be moving away at the same recession velocity which contradicts observation.

The other issue is that a Universe expanding into existing space would require the Earth to be the geometrical centre of the Universe, which violates the cosmological principle.

Redshift is a direct consequence of this cosmological scale factor.

Steven

erick (Eric) · #19 16-11-2009, 10:04 AM

Quote:

Originally Posted by Paddy

Sorry to be pedantic, Phil, but most doctorates in any field of science or humanities are called Doctorates of Philosophy (literally love of knowledge) and are not in the subject we call "philosophy". The author is most likely a physics/astronomy post graduate.

When I mentioned my Doctorate of Philosophy to some people they would say - we thought you were studying chemistry??

Redshift (Phil) · #20 16-11-2009, 08:30 PM

Thanks Patrick. I stand corrected.

And to all those with a Doctorate of Philosophy I humbly apologise.