How Can a Star Be Older Than the Universe? • Hacker News Board

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

#61

Post by temp1999 » Wed, Oct 16, 2019, 10:50 PM UTC

ergothus wrote: post #58

semi-extrinsic wrote: post #49

Earlier quoted context omitted.

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".

Not the above poster, but I want to understand. I have half-understood thoughts that conflict with each other. Any help showing where I misunderstand is appreciated, but this is probably a failure of my brain to be able to cope. * All space was contained in the big bang, so "everywhere simultaneously" makes sense from that perspective. * ...but the idea that space is expanding implies an outer "edge" (, which doesn't…

[0,1] is not less infinite than [0,2]. Also the less does not need quotes, there is an ordering of infinities.

Edit: typo

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

#62

Post by dotancohen » Wed, Oct 16, 2019, 10:56 PM UTC

inetknght wrote: post #4

Why can't the star be older because of relativity? I imagine that, particularly in the early universe while everything was nearer to everything else, relative background gravity was higher (and thus relative time) is different than now. Would the star not age at a different rate if it's a remnant from violent beginnings of the universe?

The star would need to be in a _lighter_ background gravity than us, to appear older to us.

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

#63

Post by amelius » Wed, Oct 16, 2019, 11:06 PM UTC

mannykannot wrote: post #54

TallGuyShort wrote: post #43

Earlier quoted context omitted.

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…

Perhaps a big bang that's 'just' an explosion in spacetime, rather than of spacetime, would not work with known physics because that concentration of that much matter would be a black hole? Until now, I never thought to ask anyone.

I'm not a physicist but I suspect this comment hits the nail on the head. You can only "undo" a black-hole by expanding the space it is embedded in.

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

#64

Post by accnumnplus1 » Wed, Oct 16, 2019, 11:13 PM UTC

Does the microwave background come from the centre of the universe where the big bang was; and the light from stars on the far side, flying in the opposite direction to us, take longer to reach us than the microwave background does?

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

#65

Post by namirez » Wed, Oct 16, 2019, 11:14 PM UTC

ajay-d wrote: post #59

GN-z11 is a galaxy that's 32 billion light years away. Here's the note from wikipedia: At first glance, the distance of 32 billion light-years (9.8 billion parsecs) might seem impossibly far away in a Universe that is only 13.8 billion (short scale) years old, where a light-year is the distance light travels in a year, and where nothing can travel faster than the speed of light. However, because of the expansion of t…

Also, despite the age of the universe (13.8B years), the diameter of the observable universe is 93 billion light years. That's because the universe expanded (and probably still is expanding) faster than light.

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

#66

Post by tomrod » Wed, Oct 16, 2019, 11:16 PM UTC

mannykannot wrote: post #54

TallGuyShort wrote: post #43

Earlier quoted context omitted.

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…

Perhaps a big bang that's 'just' an explosion in spacetime, rather than of spacetime, would not work with known physics because that concentration of that much matter would be a black hole? Until now, I never thought to ask anyone.

I think string theory approaches this idea with the holographic principle: https://en.m.wikipedia.org/wiki/Holographic_principle

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

#67

Post by svachalek » Wed, Oct 16, 2019, 11:24 PM UTC

TallGuyShort wrote: post #24

bardworx wrote: post #20

Earlier quoted context omitted.

But why would that matter? If, like you said "...all originated from a similar point in time and space and that it rapidly expanded outward", any star forming next to it would be pushed out of the observable edge. Hence, no one would ever know if a star was there in the first place.

Our universe in it's recent state is incredibly sparse. What would have pushed a star out of the observable edge, exactly?

The Big Bang was not (or not only) an expansion of matter, it's an expansion of space itself; the known universe is an enormous place that expanded out of a microscopic one. If there was space before the Big Bang, presumably it's been displaced by the sudden appearance of the entire universe as we know it. Not just the things in it but all the empty parts too, especially the empty parts.

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

#68

Post by johnklos » Wed, Oct 16, 2019, 11:25 PM UTC

I would REALLY love to read this, but space.com is one of those asshole sites that wants to take a gigabyte of memory (I'm not joking) and wants a full 30 to 45 seconds of CPU just to load the page.

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

#69

Post by zarriak » Wed, Oct 16, 2019, 11:30 PM UTC

johnklos wrote: post #68

I would REALLY love to read this, but space.com is one of those asshole sites that wants to take a gigabyte of memory (I'm not joking) and wants a full 30 to 45 seconds of CPU just to load the page.

It loads almost instantly without javascript. I can understand not using adblocking but why are you complaining about loading times when not using umatrix or noscript?

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

#70

Post by marzell » Wed, Oct 16, 2019, 11:36 PM UTC

ajay-d wrote: post #59

GN-z11 is a galaxy that's 32 billion light years away. Here's the note from wikipedia: At first glance, the distance of 32 billion light-years (9.8 billion parsecs) might seem impossibly far away in a Universe that is only 13.8 billion (short scale) years old, where a light-year is the distance light travels in a year, and where nothing can travel faster than the speed of light. However, because of the expansion of t…

Seriously... what's the difference between 'universe expansion' and 'travel'? A particle can't travel faster than c but it can effectively if the universe expands in addition to its travel speed? Are there any established sci-fi concepts that replace the concepts of wormholes with 'universe compression'?