The Logic Of The Big Bang

[PrimalMinister]

Ok, so we have all this evidence and models for the big bang.

 

Do these models, using the same logic that got us from the beginning to now to get us from now till the end, accuratly predict the fate of the universe?

[Strange]

1 minute ago, PrimalMinister said:

Ok, so we have all this evidence and models for the big bang.

 

Do these models, using the same logic that got us from the beginning to now to get us from now till the end, accuratly predict the fate of the universe?

They do predict several possible outcomes. we can't know if these are accurate or not.

It used to be thought that the expansion would gradually slow down (because of gravity) and then the universe would start to collapse again. Perhaps resulting in a "Big Bounce" and starting a new universe.

However the discovery that the rate of expansion has started accelerating makes that less likely so the most generally accepted prediction is that the universe will continue expanding and that in the far distant future we will so no other galaxies beyond our own.

Much further out than that, all the stars will die (run out of fuel) and everything will cool to the same temperature resulting in what is known as the "heat death" of the universe. 

[PrimalMinister]

3 minutes ago, Strange said:

"heat death" of the universe. 

What happens after that? Does time cease to exist because there is no longer anything changing? Or do things keep moving about in a basic primodal soup?

[Strange]

4 minutes ago, PrimalMinister said:

What happens after that? Does time cease to exist because there is no longer anything changing? Or do things keep moving about in a basic primodal soup?

Time can't cease to exist. But the universe would become increasingly cold. It would consist of cold, dead planets orbiting cold, dead stars.

There is a podcast interview with the cosmologist Kate Mack about the subject here: http://titaniumphysicists.brachiolopemedia.com/2018/09/09/episode-78-the-heat-death-of-the-universe-with-ken-liu/

[PrimalMinister]

1 minute ago, Strange said:

Time can't cease to exist.

So the universe from now on is eternal?

[Strange]

Just now, PrimalMinister said:

So the universe from now on is eternal?

Asfar as we can tell. Eternal but dead.

[PrimalMinister]

Is it possible that a new science could emerge that can explain how to go from a dead universe to a living one, like a new science that scoops up all the deadness and compresses it into a point creating a new big bang?

[Strange]

2 minutes ago, PrimalMinister said:

Is it possible that a new science could emerge that can explain how to go from a dead universe to a living one, like a new science that scoops up all the deadness and compresses it into a point creating a new big bang?

It is entirely possible that new science can change our view. After all, it has changed it once (from "big bounce" to "heat death").

Isaac Asimov wrote a short story about this a few years ago: http://www.multivax.com/last_question.html

 

[beecee]

1 hour ago, PrimalMinister said:

Ok, so we have all this evidence and models for the big bang.

The BB "is" the model overwhelmingly supported based on observational evidence.

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Do these models, using the same logic that got us from the beginning to now to get us from now till the end, accuratly predict the fate of the universe?

As you have been told many times, the BB is the supported model/theory from t+10-43 seconds. 

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What happens after that? Does time cease to exist because there is no longer anything changing? Or do things keep moving about in a basic primodal soup?

Space and Time will go on forever, but stars, planets, BH's etc will undergo total decay over many trillions of years culminating with BH evaporation and perhaps even proton decay.

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Is it possible that a new science could emerge that can explain how to go from a dead universe to a living one, like a new science that scoops up all the deadness and compresses it into a point creating a new big bang?

I don't see how a decayed universe would be able to assemble itself again, particularly since the observed acceleration all but rules out any possible recollapse.

Edited September 24, 2018 by beecee

[PrimalMinister]

OK, well instead of having a big bang/heat death as a one off event, why not just repeat it. Instead of having just one big one, why not have many small ones, everywhere, a small bang followed by a small death say happening billions of time a second. You seem to say things go through the process of coming to life, then dying. Just look at this same process from a different angle.

[beecee]

4 minutes ago, PrimalMinister said:

OK, well instead of having a big bang/heat death as a one off event, why not just repeat it. Instead of having just one big one, why not have many small ones, everywhere, a small bang followed by a small death say happening billions of time a second. You seem to say things go through the process of coming to life, then dying. Just look at this same process from a different angle.

Cosmologists have come up with many scenarios of possible speculative scenarios, that are outside the prediction of our current models such as the BB and GR...but speculation it remains at this time.

[Strange]

12 minutes ago, PrimalMinister said:

OK, well instead of having a big bang/heat death as a one off event, why not just repeat it. Instead of having just one big one, why not have many small ones, everywhere, a small bang followed by a small death say happening billions of time a second. You seem to say things go through the process of coming to life, then dying. Just look at this same process from a different angle.

There is a model called "eternal inflation" that proposes something like this. That "big bangs" are happening continuously. https://en.wikipedia.org/wiki/Eternal_inflation

But obviously, your suggestion makes no sense. We know the universe started off in a hot dense state and has cooled over billions of years. You can't repeat that in a billionth of a second. That is nonsensical.

 

[PrimalMinister]

44 minutes ago, Strange said:

After all, it has changed it once (from "big bounce" to "heat death").

So was it the big bounce an objective fact before it became opinion or was it always opinion. Is the heat death now a fact?

[Strange]

3 minutes ago, PrimalMinister said:

So was it the big bounce an objective fact before it became opinion or was it always opinion. Is the heat death now a fact?

It was a hypothesis.

Science doesn't really deal in opinions or facts.

Edited September 24, 2018 by Strange

[PrimalMinister]

3 minutes ago, Strange said:

Science doesn't really deal in opinions or facts.

You bang on about evidence all the time, the evidence is all the facts is it not?

[beecee]

22 minutes ago, PrimalMinister said:

So was it the big bounce an objective fact before it became opinion or was it always opinion. Is the heat death now a fact?

The Big Bounce or Oscillating hypothetical, was an idea in the fifties, along with the Steady State and Big Bang hypothetical and all were reasonably on equal status, until the CMBR was discovered, which gave the BB the status over the other two. Nothing is an objective fact as you love to keep harping on. A scientific theory stands as long as it aligns with observational evidence, and is always open for modification or total change, but by the same token, grow in certainty over time and continuing success. The BB, GR and the theory of the evolution of life are objective scientific theories based on the tried and true scientific methodology.

[PrimalMinister]

30 minutes ago, PrimalMinister said:

After all, it has changed it once (from "big bounce" to "heat death").

So the big bounce was an opinion?

[beecee]

22 minutes ago, PrimalMinister said:

You bang on about evidence all the time, the evidence is all the facts is it not?

No. The evidence supports a model/theory and makes that theory objective.

1 minute ago, PrimalMinister said:

So the big bounce was an opinion?

The Big Bounce was a hypothetical scenario that we have no evidence for.

[Strange]

15 minutes ago, PrimalMinister said:

You bang on about evidence all the time, the evidence is all the facts is it not?

That is a deep philosophical question that people argue about endlessly. Fact, like truth, is a very slippery and dangerous concept.

I would not use "fact" to refer to evidence. For example, once upon a time it was thought that all swans were white. Every swan that anyone had ever seen was white. People had known about swans for thousands of years. There was no reason to think that swans came in any other colour. So it was a generally accepted "fact" that "swans are white".

Until people went to Australia and found out that there are black swans. So the "fact" is no longer a "fact". But it was never an opinion, either. Because it was based on the best available evidence at the time. So, in scientific terms, it was a theory. Now the theory has been updated to say that "swans are either white or black". If we ever find a pink swan, then the theory will be updated again. That is how science works.

6 minutes ago, PrimalMinister said:

So the big bounce was an opinion?

No. It was a hypothesis. It was based on the evidence available at the time.

Science does not deal with facts or opinions.

[Airbrush]

16 hours ago, Strange said:

Much further out than that, all the stars will die (run out of fuel) and everything will cool to the same temperature resulting in what is known as the "heat death" of the universe. 

Would it be possible for a civilization to avoid the heat death of the universe if they had a fusion reactor?  All they need to do it gather hydrogen and throw it into the fusion reaction and generate energy beyond the death of the last red dwarf.

Edited September 25, 2018 by Airbrush

[zapatos]

18 hours ago, Strange said:

 

However the discovery that the rate of expansion has started accelerating makes that less likely so the most generally accepted prediction is that the universe will continue expanding and that in the far distant future we will so no other galaxies beyond our own.

 

Would we see no other galaxies beyond our own, or would we still remain gravitationally bound to the galaxies in our supercluster?

[beecee]

42 minutes ago, zapatos said:

Would we see no other galaxies beyond our own, or would we still remain gravitationally bound to the galaxies in our supercluster?

Eventually, all distant galaxies would move beyond our view, and our local group would merge in time under gravity.

[zapatos]

2 minutes ago, beecee said:

Eventually, all distant galaxies would move beyond our view, and our local group would merge in time under gravity.

So given a long enough period of time, would all bodies in our merged galaxy merge into a single entity (black hole or whatever)?

[beecee]

On 9/25/2018 at 1:40 PM, zapatos said:

So given a long enough period of time, would all bodies in our merged galaxy merge into a single entity (black hole or whatever)?

I would say  that in a few hundred trillions of years,  even BH's will have evaporated via Hawking Radiation...but in answer to what you have asked, probably the angular momentum and Inertia of most bodies. And of course tremendous forces need to be involved in squeezing any mass beyond its Schwarzchild limit.

[Airbrush]

On ‎9‎/‎24‎/‎2018 at 8:35 PM, beecee said:

Eventually, all distant galaxies would move beyond our view, and our local group would merge in time under gravity.

To be precise our "Local Group" is the name for our local cluster of 54 galaxies.  "Supercluster" is a word for ALL galaxies and galaxy clusters that are forever bound together by gravity.

"The Local Group is the galaxy group that includes the Milky Way. The Local Group comprises more than 54 galaxies, most of them dwarf galaxies. Between 1 billion and 1 trillion years from now, they will collide and form a single galaxy. Its gravitational center is located somewhere between the Milky Way and the Andromeda Galaxy. The Local Group has a diameter of 10 Mly (3.1 Mpc) (about 10²³ meters) and has a binary (dumbbell)^[1] distribution. The group itself is a part of the larger Virgo Supercluster, which may be a part of the Laniakea Supercluster."

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