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How Can a Star Be Older Than the Universe?

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Re: How Can a Star Be Older Than the Universe?

#41

Post by swebs »

TallGuyShort wrote: post #22
cbzbc wrote: post #18

Earlier quoted context omitted.

(That) Space was also created by the big bang.

What's the evidence of that? I'm not arguing, but between cosmic background radiation, doppler shift of stars and the relationship between speed / distance, all the evidence of the big bang I've heard doesn't suggest anything about space itself.

The theory of cosmic expansion states that space is being created between objects in the universe (rather than them simply moving away from each other). Therefore, all space in the universe, or at least the ~90 billion light year observable universe, was created by the big bang itself.

Re: How Can a Star Be Older Than the Universe?

#42

Post by guerrilla »

lottin wrote: post #39

Here we go again... "scientists would look at the ripples in the fabric of space and time". Am I the only one who finds this expression very confusing? What fabric? There is no fabric. Space and time are coordinates. They do not exist physically at all. There cannot be a fabric of space and time.

Are you sure that's how general relativity sees spacetime? What about graviational waves and vacuum energy?

> On 11 February 2016, the LIGO and Virgo Scientific Collaboration announced they had made the first direct observation of gravitational waves.

https://en.wikipedia.org/wiki/Gravitational_wave

Re: How Can a Star Be Older Than the Universe?

#43

Post by TallGuyShort »

amelius wrote: post #38
TallGuyShort wrote: post #22

Earlier quoted context omitted.

What's the evidence of that? I'm not arguing, but between cosmic background radiation, doppler shift of stars and the relationship between speed / distance, all the evidence of the big bang I've heard doesn't suggest anything about space itself.

The universe is expanding. This started at some point, and I suppose the theory says that it started at the point where there was no space.

Correct me if any of the following is wrong, though: when we say the universe is expanding, we mean that matter is spreading out. The further apart the matter is, the faster it's spreading out. If we back-trace the position of stars, they all coincide at roughly the same point in time and space. This led us to believe that at some point in time all of this matter was together, incredibly dense, and in a very "hot", high-energy state. This led to the prediction that has since been confirmed, that from the furthest reaches of the observable universe, we would see cosmic background radiation. And as time goes, that cosmic background radiation is getting further and further away, so the observable bubble is expanding.

Maybe I have some of that wrong, but that's my understanding. None of that means that the fabric of space (as in space-time) is actually expanding. And even if it did, none of that means that nothing could have existed outside of the observable bubble billions of years ago, and could have since been passed by the observable edge and now be inside that observable bubble. Unless maybe the source of the background radiation was still dense / high-energy enough to absolutely obliterate everything in it's path. And maybe it was? But I just don't see how we can reason about what was outside of the observable bubble.

Re: How Can a Star Be Older Than the Universe?

#44

Post by eljimmy »

lottin wrote: post #39

Here we go again... "scientists would look at the ripples in the fabric of space and time". Am I the only one who finds this expression very confusing? What fabric? There is no fabric. Space and time are coordinates. They do not exist physically at all. There cannot be a fabric of space and time.

https://en.wikipedia.org/wiki/Spacetime

Re: How Can a Star Be Older Than the Universe?

#45

Post by tiborsaas »

lottin wrote: post #39

Here we go again... "scientists would look at the ripples in the fabric of space and time". Am I the only one who finds this expression very confusing? What fabric? There is no fabric. Space and time are coordinates. They do not exist physically at all. There cannot be a fabric of space and time.

It's a metaphor to help humans grasp it better. Space and time does exists physically.

Does a shortest path between you and your workplace exists that you can traverse? Is it a straight line? No, it's not, but there's one path that you as a being can walk along physically. The buildings, roads, obstacles force you to diverge from the ideal straight line. That's another analogy of what space & time is. Fabric is just shorter.

Re: How Can a Star Be Older Than the Universe?

#46

Post by TallGuyShort »

swebs wrote: post #41
TallGuyShort wrote: post #22

Earlier quoted context omitted.

What's the evidence of that? I'm not arguing, but between cosmic background radiation, doppler shift of stars and the relationship between speed / distance, all the evidence of the big bang I've heard doesn't suggest anything about space itself.

The theory of cosmic expansion states that space is being created between objects in the universe (rather than them simply moving away from each other). Therefore, all space in the universe, or at least the ~90 billion light year observable universe, was created by the big bang itself.

Okay - that makes sense. Upon reviewing the Wikipedia page, that sounds to be a much more accepted consensus than I thought it was, with more reasons to accept it than I thought.

Re: How Can a Star Be Older Than the Universe?

#47

Post by ecnahc515 »

TallGuyShort wrote: post #43
amelius wrote: post #38

Earlier quoted context omitted.

The universe is expanding. This started at some point, and I suppose the theory says that it started at the point where there was no space.

Correct me if any of the following is wrong, though: when we say the universe is expanding, we mean that matter is spreading out. The further apart the matter is, the faster it's spreading out. If we back-trace the position of stars, they all coincide at roughly the same point in time and space. This led us to believe that at some point in time all of this matter was together, incredibly dense, and in a very "hot", h…

> when we say the universe is expanding, we mean that matter is spreading out

It's been a while, but I recall reading in a book that's actually the space between everything that's expanding, much like you state in your second paragraph. For example, if you blow up a balloon, two points on it will appear to be moving apart from each other even though they're stationary.

I believe this Forbes article is in agreement: https://www.forbes.com/sites/startswithabang/2018/02/10/ask-...

Re: How Can a Star Be Older Than the Universe?

#49

Post by semi-extrinsic »

TallGuyShort wrote: post #37
sorenn111 wrote: post #32

Earlier quoted context omitted.

Quark Gluon Plasma (observed at the RHIC), at really early in the universe there was too much temperature and pressure to have stars or even atoms. At least that's my understanding.

Yes but Quark Gluon Plasma existed immediately following the Big Bang. We arrive at the Big Bang by reverse engineering lots of evidence we see in the universe. What evidence is there that nothing else currently inside the bubble of the observable universe could possibly have been there, very far away from the Big Bang, at the time of the Big Bang? I don't see why I'm being down-voted because as of yet no one has ans…

All the evidence suggests that Big Bang did not happen at one identifiable point. Instead it happened everywhere simultaneously. So there is no place in our universe "very far away from the Big Bang".
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