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Stephen Hawking's explosive new theory - Comments

squinky's Avatar Comment 1 by squinky

Ah, first!

This theory is intellectually gratifying because it starts with no a priori assumptions--it's natural selection from the start at cosmic scale. Hopefully, I'll live long enough to see measurements to codify such a theory.

Mon, 30 Jun 2008 06:31:00 UTC | #191557

alexmzk's Avatar Comment 2 by alexmzk

lovely. as a complete ignoramus in this area, i wondered a wee bit about how quantum physics tied in with the early state of the big bang.
very nice.

Mon, 30 Jun 2008 06:45:00 UTC | #191565

Manson's Avatar Comment 3 by Manson

Prof Stephen Hawking has come up with a new idea...


The new theory believes original estimates of Big Bang expansion are wrong


"This proposal, with volume weighting, can explain why the universe inflated," Prof Hawking tells New Scientist.


So which is it?

- an idea
- a proposal
- a theory
- a scientific theory

How about...
- a conjecture
- a guess
- a hypothesis
- really cool idea after a few beers and a joint

No wonder the vast majority of the lay-person pubic doesn't "believe" in the scientific theory of evolution. We all need to start using consistent language when communicating to the public. It really does do damage.

like a blend of a God's eye view of every conceivable kind of creation


And why do science editors CONTINUE to feel the need to bring the word God and creation into science articles. Why not Gods or Space Aliens or Spaghetti Monsters.

Mon, 30 Jun 2008 06:48:00 UTC | #191567

konquererz's Avatar Comment 4 by konquererz

I love new theories. I can't wait to see how this one progresses. Whether it fails or succeeds, this is the stuff that makes science fun and exciting.

I do agree they need to stop using the "god" language where they don't mean "God". It really makes it difficult for non-believers to get it.

Mon, 30 Jun 2008 06:57:00 UTC | #191581

Roel's Avatar Comment 5 by Roel

Come on, Manson, it's a newspaper article for goodness' sake!

Mon, 30 Jun 2008 07:02:00 UTC | #191586

Manson's Avatar Comment 6 by Manson

Roel,

Yeah, you're probably right. I must say I am a bit grouchy today. :)

That said, you must admit, the inconsistencies don't particularly lend themselves to clarity.

Mon, 30 Jun 2008 07:16:00 UTC | #191594

Oystein Elgaroy's Avatar Comment 7 by Oystein Elgaroy

This is definitely an idea, not a theory. I am no expert on the "sum over histories" approach to quantum gravity, but as far as I know there are technical difficulties with it that are yet to be resolved. However, it seems like a very sensible step to take the state of the universe today as a starting point instead of unknown initial conditions at the Big Bang. It will be interesting to see if they can derive interesting observable predictions from their idea.

For those who want to see the technical details the manuscript is available at
http://arxiv.org/abs/0711.4630

Mon, 30 Jun 2008 07:42:00 UTC | #191603

riki's Avatar Comment 8 by riki

There was also an article in New Scientist a few days ago

Hawking 'close' to explaining universe's inflation
http://space.newscientist.com/article/mg19826624.300

Mon, 30 Jun 2008 07:46:00 UTC | #191605

Steve Zara's Avatar Comment 9 by Steve Zara

Comment #201768 by Oystein Elgaroy

I am no expert on the "sum over histories" approach to quantum gravity, but as far as I know there are technical difficulties with it that are yet to be resolved.


That seems a very polite response, considering there isn't yet any practical theory of quantum gravity.

However, it seems like a very sensible step to take the state of the universe today as a starting point instead of unknown initial conditions at the Big Bang.


I'd like to add that this is a sensible use of the much-maligned anthropic principle... this is the universe we observe, so it makes sense to explain this universe, with its conditions.

Mon, 30 Jun 2008 07:56:00 UTC | #191611

Oystein Elgaroy's Avatar Comment 10 by Oystein Elgaroy

Comment#201776 by Steve Zara

That seems a very polite response, considering there isn't yet any practical theory of quantum gravity


At least the "sum over histories"-approach has more modest goals than string theory and starts from things we know exist: four-dimensional spacetime, gravity and quantum mechanics.

But it should be noted that the no boundary proposal (which seems to be assumed in the paper in question) is just one of many choices for the wave function of the Universe, and there are no obvious reasons, besides aesthetic ones, why this particular choice is preferable.

Mon, 30 Jun 2008 08:21:00 UTC | #191633

mordacious1's Avatar Comment 11 by mordacious1

Gee Toto, things are labeled theories pretty quickly around here.

Working backwards from what exists now is not new, just not as popular as it used to be.

This "theory":
"fits nicely with string theory-the most popular candidate for the theory of everything". It reminds me of that old muffler shop commercial "Will that muffler fit my car?" "We will make it fit" (shows hammer)

Mon, 30 Jun 2008 08:53:00 UTC | #191666

bstani's Avatar Comment 12 by bstani

Has someone else found it amusing this series of related news?

# Hawking warns Government over 'disastrous' science funding cuts
# Stephen Hawking seeks 'Einsteins of Africa'
# Hawking: Man must leave planet Earth

Seems like Hawking, being disgruntled over recent science funding decisions, is seeking 'Einsteins of Africa' to leave planet Earth. ^__^

Mon, 30 Jun 2008 09:35:00 UTC | #191691

beelzebub's Avatar Comment 13 by beelzebub

Hmm... Are they saying "Lets take an idea that gives an infinite number of answers, then pick the ones we like"? Isn't this a wee bit like the creationists saying "Here's the conclusion, now let's try and find evidence to support it"?

Mon, 30 Jun 2008 10:09:00 UTC | #191711

Oystein Elgaroy's Avatar Comment 14 by Oystein Elgaroy

Comment#201876 by beelzebub

No, they take the current state of the universe and try to say something about what constraint it puts on the initial conditions for the Universe. Assuming, of course, that their model is correct. It is speculative, just like all other attempts to figure out how the Universe started. But I think it is too harsh to compare this idea and similar cosmological speculations to creationist drivel.

Mon, 30 Jun 2008 10:57:00 UTC | #191741

Apathy personified's Avatar Comment 15 by Apathy personified

Thanks for the link (Comment #201768) Oystein.
What's your opinion on string theory?

Mon, 30 Jun 2008 11:00:00 UTC | #191746

decius's Avatar Comment 16 by decius

My understanding is that in theoretical physics and in cosmology the word theory has less stringent requirements than in other fields of science. Namely, the math must add up, the mechanisms must be plausible and in tune with available data.

The real question is when and if it will become an accepted theory.
It would be interesting to know if viable ways of testing it have already been suggested, and when it will be possible, if ever, to test it.

Oystein, did I say something stupid? :)

Edited for mistakes

Mon, 30 Jun 2008 11:07:00 UTC | #191749

Oystein Elgaroy's Avatar Comment 17 by Oystein Elgaroy

Comment #201913 by Apathy personified

I don't know if I am entitled to having an opinion since my knowledge of it is rudimentary. But here goes: I think there are aspects of it that are extremely attractive. For example, string theory is often ridiculed for requiring extra spatial dimensions, but I think it is remarkable that the theory actually predicts this number. Just write down the equations of motion for a relativistic string in N spatial dimensions and require them to be consistent with quantum mechanics, and then the number of spatial dimensions is fixed.

Having said that, I think the main problem with string theory is that it has been oversold for too long. For more than 20 years is has been described by its proponents as a the Theory of Everything, but they have yet to come up with a single testable prediction. And they don't know how to do the calculations to check that they can reproduce things like the particle masses in the Standard Model.

I have great respect for the people who work on string theory, the great majority of them are way smarter than me. But I won't jump and cheer until they actually make a connection between their calculations and the real world. They have got to produce numbers that can be measured. In the meantime I think it is very important that other approaches to quantum gravity and unification of forces are explored.

Comment #201916 by decius

I agree that the word "theory" is often used in a sloppy way in physics. Quantum mechanics and the general theory of relativity definitely deserve to be called theories. String theory does not, since we don't even know if it applies to the real world. I also prefer to talk about the Big Bang model rather than the Big Bang theory.

When it comes to the model of Hawing et al., it is still to sketchy to be put to a real test. So far it only contains a scalar field (to drive inflation) coupled to gravity. And no, you did not say anything stupid. :)

Mon, 30 Jun 2008 11:33:00 UTC | #191761

Fanusi Khiyal's Avatar Comment 18 by Fanusi Khiyal

With respect - how the hell would they prove this? I know and you know that a theory is only a theory if it has testable predictions.

Mon, 30 Jun 2008 11:37:00 UTC | #191764

Steve Zara's Avatar Comment 19 by Steve Zara

I don't think String Theory should be ridiculed for having multiple dimensions. The problem is that it has indeed been oversold. There are some amazing people working on String theory, from Brian Greene to Edward Witten.

It isn't entirely true that String theory hasn't connected with the real world. There have been some amazing insights into black holes from string theory, but nothing that is experimentally verifiable.

My personal concern is that String Theory isn't even the kind of thing that should be considered as a candidate for ultimate reality. It would, even if true, explain the origin of all particles and forces, but it gives no insight into quantum uncertainty.

Mon, 30 Jun 2008 11:51:00 UTC | #191769

Apathy personified's Avatar Comment 20 by Apathy personified

Comment #201929 by Oystein Elgaroy,
Thanks for the reply.
My only 'real' exposure to string theory has been through Peter Woit's book (Not Even Wrong) and Lee Smolin's book (The Trouble with physics), so i may have a slightly negative attitude towards it.
I can see the potential in it but i think that after 20 years, alarm bells should ring and new approaches should be tried.

Mon, 30 Jun 2008 12:00:00 UTC | #191776

clatz's Avatar Comment 21 by clatz

Nice diagram ...

Hey, I can see my house from here!

"ahem"

As you were.

Mon, 30 Jun 2008 12:08:00 UTC | #191780

Oystein Elgaroy's Avatar Comment 22 by Oystein Elgaroy

Comment #201937 by Steve Zara

I am not sure I would call the derivation of the Bekenstein-Hawking formula for the entropy of a black hole a connection with the real world. Hawking radiation has not been measured yet, and the "black holes" considered in the string theory derivation are very different from astrophysical black holes. It is more precise to call them black hole-like states.

But I agree that there is something very unsatisfactory about taking quantum mechanics for granted as one does in string theory. It is hard to argue with success, and quantum mechanics is remarkably successful. But it is hard to make sense of, and has nothing of the inevitability of, say, Einstein's general theory of relativity. To me, quantum mechanics is a set of rules one applies to a classical theory. I would like to know whether these rules can be derived, or whether they are approximations to a deeper theory.

Mon, 30 Jun 2008 12:14:00 UTC | #191785

Apathy personified's Avatar Comment 23 by Apathy personified

Steve,
I personally don't think we have enough knowledge to actually consider a theory of everything. The standard model has some 'small black clouds on the horizon' (to quote lord kelvin) - such as the neutrino masses, the constants whose values have to be experimentally determined, etc.
But, to pose a contraversial question,
What would be more interesting, from a scientific perspective - The LHC finding or not finding the higgs boson?

Note: I'm well aware what a £4bn 'failed' experiment would do for the future of particle physics.

Mon, 30 Jun 2008 12:15:00 UTC | #191786

al-rawandi's Avatar Comment 24 by al-rawandi

Fanusi,





Let's talk shariah and hijack the thread....


*ducks*

Mon, 30 Jun 2008 12:16:00 UTC | #191787

decius's Avatar Comment 25 by decius

Oystein,

thanks for your reply.

Mon, 30 Jun 2008 12:20:00 UTC | #191789

Jiten's Avatar Comment 26 by Jiten

Manson wrote :

And why do science editors CONTINUE to feel the need to bring the word God and creation into science articles. Why not Gods or Space Aliens or Spaghetti Monsters.
I agree completely! Always fucking God in a cosmology article especially one with Hawking in it. God god god god fucking god. Enough !

Mon, 30 Jun 2008 12:21:00 UTC | #191790

ggab7768's Avatar Comment 27 by ggab7768

I am a total string theory whore.
I admit that my understanding is rudamentory, and I may not have the grey matter to grasp it any further. I also know that it has been pushed way too hard for way toolong, but I can't help myself.
I just get all giddy!!
I want it to be right so I can walk around like a high school kid going "Dude, I was into string theory way before you guys."
I really am a sad little man sometimes.

Mon, 30 Jun 2008 12:27:00 UTC | #191795

Oystein Elgaroy's Avatar Comment 28 by Oystein Elgaroy

Comment #201954 by Apathy personified

There are many different variants of the Higgs boson(s) depending on, e.g., whether you include supersymmetry or not. The worst case scenario, I think, would be if they were to see only the Standard Model Higgs at LHC and nothing else. Then they would just have confirmed the SM, but left us without a clue as to what lies beyond.

Mon, 30 Jun 2008 12:32:00 UTC | #191798

Apathy personified's Avatar Comment 29 by Apathy personified

Interesting.
I'm more intrigued by the idea that what if NONE of the variants of the higgs boson or any supersymmetric particles are found?
What if the SM is shown to be a 'low-level' approximation to a deeper theory (as you hint at in comment 201953), but technically wrong (rough analogy to the newton mechanics relation to the relativities)?

I say this an someone about to start the final year of a theoretical physics degree, i have to make choices about phd's soon (not even sure i want to do one!) - so i want the outcome that produces the largest amount of new physics that needs doing - so they'll still be jobs for me!

Mon, 30 Jun 2008 13:01:00 UTC | #191807

Oystein Elgaroy's Avatar Comment 30 by Oystein Elgaroy

Comment #201975 by Apathy personified

If they don't find any kind of Higgs boson at the LHC, then the most popular idea of how particles get their masses is wrong. There are other ideas around, for example something called technicolour. But if nothing beyond the SM is seen at the LHC, then I guess we will not know which directions to explore. And worse, it will be hard to get funding for a bigger accelerator. But for a theorist I guess the scenario where no Higgs and no supersymmetry is found will be the best.

Mon, 30 Jun 2008 13:10:00 UTC | #191811