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Physicists Debate Hawking’s Idea That the Universe Had No Beginning

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Re: Physicists Debate Hawking’s Idea That the Universe Had No Beginning

#131

Post by heimdall »

newsoul2019 wrote: post #126
EMM_386 wrote: post #118

Pure nothingness has no potential for creation. The laws of physics don't invent themselves, so it would seem that true "nothing" never existed. I'm not talking about the quantum soup of the vacuum of space, because that is something. If we take Hawking's idea that the universe smoothed out to a zero point where there was no time and nothing else, how does that point because laws of physics, gravity, etc? What proper…

Is there a theory that the beginning and the ending of the universe are directly connected to each other? And that time doesn't so much start over and return to the starting point on a circle, so to speak?

The Big Bounce! https://en.wikipedia.org/wiki/Big_Bounce

To me it's more satisfying than the idea of https://en.wikipedia.org/wiki/Heat_death_of_the_universe

Re: Physicists Debate Hawking’s Idea That the Universe Had No Beginning

#132

Post by antidesitter »

jdironman wrote: post #89
sarego wrote: post #83

Earlier quoted context omitted.

Curious to know why that is. Would you mind expanding?

Because if we have not beginning, we have no purpose. If we have no purpose, this is all really for nothing. I am not arguing whether it is or not, or whether there is a beginning, but lets look at it this way... You woke up this morning, that was the beginning of this day at night you will rest. Now, lets say there is no memory or record of 'waking up' beginning, we therefor cannot anticipate an end and everything w…

Countered the downvote because I’m interested in this line of reasoning. Could you expand on that? Why do you think having no memory of “waking up” to existence makes it less meaningful?

I'm reminded of the following quote by Alan Watts from The Way of Zen:

To the Taoist mentality, the aimless, empty life does not suggest anything depressing. On the contrary, it suggests the freedom of clouds and mountain streams; wandering nowhere; of flowers in impenetrable canyons, beautiful for no one to see, and of the ocean surf forever washing the sand, to no end.

Re: Physicists Debate Hawking’s Idea That the Universe Had No Beginning

#133

Post by raattgift »

Balgair wrote: post #123
raattgift wrote: post #110

Earlier quoted context omitted.

The hot big bang is an event in spacetime. It does not generate the manifold itself, although the geometry of the manifold necessarily reflects it, especially near the event itself. There is no evidence to support finiteness of spacetime; there is no reason why there aren't events in the infinite future. The only reason to suspect there are no events in the infinite past is a classical picture of a gravitational sing…

> and not all extensions must be infinite any examples?

> any examples?

Sean Carroll has an excellent "zoo" of ideas in a set of slides at https://www.slideshare.net/seanmcarroll/what-we-dont-know-ab... where he gives a reasonable overview of a number of ideas including those which have an earliest time (even if it is far earlier than the hot big bang), and those which do not.

Indeed, a couple of the slides touch on Hawking's idea in the article at the top: discussing or debating that particular model (and "choosing sides") is not especially new.

The references [in square brackets] on each of the slides are mostly easy enough to find via your favourite search engine.

Re: Physicists Debate Hawking’s Idea That the Universe Had No Beginning

#134

Post by _urga »

onion2k wrote: post #60
chii wrote: post #31

Earlier quoted context omitted.

> If you accept that some stuff is beyond our understanding isn't that just an elaborate way to say 'give up'? I asked religious friends of mine about what god _is_, and the common answer is that it's beyond human understanding. I don't believe that people should take things on faith, and accept that anything is beyond understanding.

isn't that just an elaborate way to say 'give up'? Accepting that we don't understand something is a first and very necessary step to even realising there's something to understand. Believing that we have the answer (eg "God made the universe!") is exactly what shuts down scientific inquiry and makes people 'give up'. I'm saying literally the opposite of that - we have to realise there's something to out there to lea…

If we accept your logic, then believing gravity to be the answer to "why things fall" would shut down scientific inquiry?

On the contrary, it was belief in the creator that opened up scientific inquiry in the minds of Johannes Kepler etc.

That the universe was not chaotic, but created by a personal being, led them to think there must be some order to it that could be studied.

Re: Physicists Debate Hawking’s Idea That the Universe Had No Beginning

#136

Post by baxtr »

irrational wrote: post #62
Balgair wrote: post #54

Earlier quoted context omitted.

Wikipedia's 'Timeline of the Far Future' is a great article on the posibilities of our universe's fate [0]. Of note are the entries near the end of the list. Year 10^(10^(50)) : Estimated time for a Boltzmann brain to appear in the vacuum via a spontaneous entropy decrease [1] Year 10^(10^(120)) : High estimate for the time for the universe to reach its final energy state, even in the presence of a false vacuum. Year…

This kind of discussion always reminds me of the Asimov story "The Last Question" https://www.multivax.com/last_question.html

Reading this, I am again reminded that technological progress is sometimes way slower than people think. Think about how the folks in the 50s/60s envisioned the time around 2000s, flying cars etc. I think the same might happen to autonomous delivery, general AI and the like.

Re: Physicists Debate Hawking’s Idea That the Universe Had No Beginning

#137

Post by tmountain »

EMM_386 wrote: post #118

Pure nothingness has no potential for creation. The laws of physics don't invent themselves, so it would seem that true "nothing" never existed. I'm not talking about the quantum soup of the vacuum of space, because that is something. If we take Hawking's idea that the universe smoothed out to a zero point where there was no time and nothing else, how does that point because laws of physics, gravity, etc? What proper…

This reminded me of a pretty good (and robust) debate with some of the world's leading physicists regarding the existence of and quantification of nothing.

2013 Isaac Asimov Memorial Debate: The Existence of Nothing

https://www.youtube.com/watch?v=1OLz6uUuMp8

Re: Physicists Debate Hawking’s Idea That the Universe Had No Beginning

#138

Post by lliamander »

galaxyLogic wrote: post #125
jawns wrote: post #119

Earlier quoted context omitted.

There's an interesting philosophical line of thought that distinguishes between things that are necessary and things that are contingent. A necessary thing must exist; it can't not exist. A contingent thing may exist, or it may not. In the classical definition of God, he has no beginning or end. He was not created by some other force. He exists necessarily. He just _is_. In fact, many theists describe God using terms…

Why is God a necessary thing?

A valid question, and not one that in my opinion (even though I am a theist) that has an argument that is both clear and compelling (look up various Ontological arguments to see the gamut).

I think it is enough to say the following things:

1. The universe clearly exists, but it is also clear that it doesn't have to exist (i.e. the universe is contingent)

2. Therefore, there must be some thing that exists, and exists of necessity, to explain the existence of the universe

3. The existence of necessary truths such as logic and mathematics are not sufficient to explain the existence of the universe, so therefore there must be something else, which could act as both the sufficient and necessary cause of the universe.

We can call this thing God, but by that we don't commit ourselves to any particular religion. At most that gets us the God of deism.

Re: Physicists Debate Hawking’s Idea That the Universe Had No Beginning

#139

Post by procgen »

quotemstr wrote: post #18

Cosmology is deeply disturbing if you think about it too long. Why should the universe exist? What is a causeless cause? How can something come from nothing? Regardless of the precise mechanisms involved, at some scale, some kind of steady-state cyclic model seems unavoidable --- the whole idea of existence not existing is bizarre and puzzling. The only way out of the causeless effect problem is to nop out of the eff…

This is the so-called 'superultimate question', whose answer defies inquiry: "Why is there something rather than nothing?"

Re: Physicists Debate Hawking’s Idea That the Universe Had No Beginning

#140

Post by raattgift »

antidesitter wrote: post #114
Balgair wrote: post #54

Earlier quoted context omitted.

Wikipedia's 'Timeline of the Far Future' is a great article on the posibilities of our universe's fate [0]. Of note are the entries near the end of the list. Year 10^(10^(50)) : Estimated time for a Boltzmann brain to appear in the vacuum via a spontaneous entropy decrease [1] Year 10^(10^(120)) : High estimate for the time for the universe to reach its final energy state, even in the presence of a false vacuum. Year…

Boltzmann brains may not occur after all [0], which is reassuring [2]. See De Sitter Space Without Dynamical Quantum Fluctuations [1]. [0] http://www.preposterousuniverse.com/blog/2014/05/05/squelchi... [1] https://arxiv.org/abs/1405.0298 [2] https://arxiv.org/abs/1702.00850

[1] is an entertaining argument, but as you know, real brains involve more than a massive free scalar. :D

I do like that balding seems to take about a light-crossing time in the cosmic no-hair in [1]. You'll need some extra patience as you approach fluctuation-free de Sitter, but there's surely infinite patience somewhere in an infinite-dimensional Hilbert space. The trick is how to walk the path from here in that space to there in that space.

I'm not sure [2]'s cognitive instability matters. We do use effective field theory all the time. Heck, even in that paper. We can have useful predictions without having final/total/exact answers.

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