Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

How Can a Star Be Older Than the Universe?

space.com

Post reply on HN
Print view View original

181–190 of 231 posts

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

#181

Post by brutt »

crooked-v wrote: post #84
ergothus wrote: post #58

Earlier quoted context omitted.

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…

> ...but the idea that space is expanding implies an outer "edge" No, it doesn't. For example: consider an infinite number of marbles in an infinitely long line, all of them are touching each other. Now, get an infinite number of helpers stationed along the infinitely long line, and have them all move the marbles in front of them to the right and stagger them out in the process, so that there's now an inch between ea…

You will need infinite amount of energy to insert spaces between these marbles. Can you point us to source of this energy?

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

#182

Post by Dylan16807 »

mannykannot wrote: post #172
Dylan16807 wrote: post #108

Earlier quoted context omitted.

> That actually demonstrates the opposite: despite the fact that the images themselves show the expansion of a grid in a two-dimensional space, each of the dots appears, from its perspective, to be at the center of the expansion, unless you either specify an absolute frame of reference, or (which amounts to the same thing) can identify the edge of the expanding region. The image isn't enough to demonstrate the differ…

> The image isn't enough to demonstrate the difference... Precisely. > ...But the speed of light is, along with the way acceleration and redshift work. Are you referring to the cosmological component of redshift? I suppose that, at least in principle, we could determine the cosmological component by first measuring the Hubble constant from the change in distance, over time, of those stars whose distance can be measur…

> Precisely.

Demonstrating the opposite is an very different thing from failing to demonstrating a difference at all.

> What set of measurements and calculation do you have in mind that avoid this circularity?

Any measurements that would actually work, I think.

You're the one asserting circularity, so I think it's up to you to explain what specific argument would be circular. Especially when you're apparently talking about theoretical arguments that swebs might have.

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

#183

Post by brutt »

madaxe_again wrote: post #180
brutt wrote: post #170

Earlier quoted context omitted.

Where is the waves? 13.8B years is too short to make Universe smooth again after such epic event. It's like to see green grass again just 1 second after nuke blast: mathematical formulas will need lot of magic constants for this to explain.

The universe isn’t smooth. The CMB is not uniform, and at a very large scale the universe is composed of attractors and voids, which stem from the anisotropy of the early universe.

For me, CMB is just light of distant stars with z=1100. Universe is composed of attractors and voids at any scale.

Anyway, I see no shockwave of any kind in CMB. Where it is? Such massive explosion, with energy of 1E53 atomic bombs and no shockwave at all just miliseconds (in scale of Universe) after the Bing Bang. How this is possible?

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

#184

Post by yorwba »

brutt wrote: post #183
madaxe_again wrote: post #180

Earlier quoted context omitted.

The universe isn’t smooth. The CMB is not uniform, and at a very large scale the universe is composed of attractors and voids, which stem from the anisotropy of the early universe.

For me, CMB is just light of distant stars with z=1100. Universe is composed of attractors and voids at any scale. Anyway, I see no shockwave of any kind in CMB. Where it is? Such massive explosion, with energy of 1E53 atomic bombs and no shockwave at all just miliseconds (in scale of Universe) after the Bing Bang. How this is possible?

What do you expect that shockwave to look like? Circles expanding from the center of the explosion?

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

#185

Post by zentiggr »

brutt wrote: post #183
madaxe_again wrote: post #180

Earlier quoted context omitted.

The universe isn’t smooth. The CMB is not uniform, and at a very large scale the universe is composed of attractors and voids, which stem from the anisotropy of the early universe.

For me, CMB is just light of distant stars with z=1100. Universe is composed of attractors and voids at any scale. Anyway, I see no shockwave of any kind in CMB. Where it is? Such massive explosion, with energy of 1E53 atomic bombs and no shockwave at all just miliseconds (in scale of Universe) after the Bing Bang. How this is possible?

Look into the inflationary portion of the BB timeline, and also add in the fact that those shockwaves have had the same 13.8B years to expand and dissipate. The CMB variations _are_ the remnants of that initial period, attenuated after all this time.

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

#186

Post by XaspR8d »

brutt wrote: post #183
madaxe_again wrote: post #180

Earlier quoted context omitted.

The universe isn’t smooth. The CMB is not uniform, and at a very large scale the universe is composed of attractors and voids, which stem from the anisotropy of the early universe.

For me, CMB is just light of distant stars with z=1100. Universe is composed of attractors and voids at any scale. Anyway, I see no shockwave of any kind in CMB. Where it is? Such massive explosion, with energy of 1E53 atomic bombs and no shockwave at all just miliseconds (in scale of Universe) after the Bing Bang. How this is possible?

What exactly are you looking for when you say shockwave? As far as we understand it, the big bang didn't explode into something, so there isn't an outer medium to "hold" a shockwave in the obvious sense of a radially expanding region of turbulence.

Also the frequently depicted diagram of expanding from a point doesn't really intend to depict the shape of it. The universe might still be infinitely large and the big bang occurred "everywhere" within it. Where is the shockwave in something that has no edge?

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

#187

Post by mannykannot »

Dylan16807 wrote: post #182
mannykannot wrote: post #172

Earlier quoted context omitted.

> The image isn't enough to demonstrate the difference... Precisely. > ...But the speed of light is, along with the way acceleration and redshift work. Are you referring to the cosmological component of redshift? I suppose that, at least in principle, we could determine the cosmological component by first measuring the Hubble constant from the change in distance, over time, of those stars whose distance can be measur…

> Precisely. Demonstrating the opposite is an very different thing from failing to demonstrating a difference at all. > What set of measurements and calculation do you have in mind that avoid this circularity? Any measurements that would actually work, I think. You're the one asserting circularity, so I think it's up to you to explain what specific argument would be circular. Especially when you're apparently talking…

At best, you are claiming that swebs' argument was correct because there is a different argument for the point he claimed has been demonstrated - but that is, as you say, "a very different thing." My original objection to that argument stands, and you have agreed that it does!

> Demonstrating the opposite is an very different thing from failing to demonstrating a difference at all.

Who is making any claim about demonstrating the opposite? You can see from my original post that I agree that spacetime is expanding; I merely disagree with swebs' argument for claiming to know that it is.

>> What set of measurements and calculation do you have in mind that avoid this circularity?

> Any measurements that would actually work, I think.

In that case, you will have no difficulty in stating, or providing citations for, the actual measurements and calculation that get the job done - if any such set of measurements exist, that is. Otherwise, your reply is equivalent to "I don't know."

My point is that I do not think that there is any set of deduced remote measurements that a) show, as a certainty, that space itself is expanding, and b) can be deduced without implicitly or explicitly assuming a position on the issue. Current cosmology expects that the large-scale measurements will show the same results as from Earth (e.g. the same Hubble constant, if and only if you derive it using the same assumption about space itself expanding), but the absence of a difference between there and Earth would fail to satisfy a).

Furthermore, I notice that you have still not made clear which redshift measurements support your claim that the issue has been resolved experimentally. A citation would be sufficient.

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

#188

Post by brutt »

yorwba wrote: post #184
brutt wrote: post #183

Earlier quoted context omitted.

For me, CMB is just light of distant stars with z=1100. Universe is composed of attractors and voids at any scale. Anyway, I see no shockwave of any kind in CMB. Where it is? Such massive explosion, with energy of 1E53 atomic bombs and no shockwave at all just miliseconds (in scale of Universe) after the Bing Bang. How this is possible?

What do you expect that shockwave to look like? Circles expanding from the center of the explosion?

Yep. Something like that: https://www.youtube.com/watch?v=EmdBFoQtVvU .

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

#189

Post by simula »

wruza wrote: post #167
crooked-v wrote: post #85

Earlier quoted context omitted.

If you're going in that direction, you may as well say that the universe is a simulation. Planck limits on measuring time and space as a continuum would pretty useful for putting a hard cap on required rendering resources per volume of space-time...

Simulation doesn’t have to obey the rules. For non-scientists it is enough to “tell” them how it works without actually rendering it, cause they’ll never check. For scientists, you have to make their brain believe that all is consistent with complex computations all the way down. Imagine that you know physics and math very good. But then simulation suddenly fails due to segfault and you realize that all your knowledg…

While a simulation doesn't have to obey the rules, any given simulation is likely to resemble a system that does adhere to rules, since a simulation is indeed simulating something else.

Even if some external observer can pause, rewind, intervene and violate rules, the reason a simulation exists is to model something else.

This "something else" will have some kind of rules, and the goal of the simulation will be similarity to the actual realm external to the simulation.

Meanwhile, a lazy replication of a model by an unmotivated author would likely impose finite quantities upon scales of interaction, since a simulation won't be able to recreate a real time version of something larger than the external reality itself.

We wouldn't notice a lagged simulation that tries to consume its footprint, but it's probable that an artificial creation would impose caps on aspects of a system to prevent runaway reactions that produce useless simulations. To us, those sorts of limitations would resemble extra physical laws, and while incontrovertible to the simulated entity, such limits might confront intuition in strange ways.

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

#190

Post by TallGuyShort »

hypothesis-3 wrote: post #51
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.

That's great, but The Big Bang is more or less chasing a status as the canonical answer to an intensely desirable question. It wants to be the answer, yet the facts don't really align with the premise of the question. We just shoe horn a litter of observations into some post-hoc rationale for how the universe "began" and then we retcon anything that doesn't make sense, when we think more deeply about it. It's fine to…

So your chief complaint is that people call it a bang instead of an expansion? Obviously from my comments you'll see I agree we're a little over-confident in all the specifics, but the question isn't "was it event 0", which I don't think anyone has really claimed, but could events, specifically this star, that occurred outside of the horizon of that expansion now have moved into our visible universe.

If that's not what you're saying I really cannot see what point you're making.

Post reply on HN