Universe

[Ray02]

Well i was wondering for a while about the universe, the theories how everything began and simply why are we here? As i know there are more and more unanswered questions ( if you answer one question another will pop out ) I read many things, but at the end they are JUST theories. I keep trying not to remind myself about it because its so complicated. What you guys think?

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[tingting44]

it just got more complicated with more unanswered questions im afraid LOL 

http://www.sciencealert.com/scientists-can-t-explain-the-bizarre-mass-of-objects-orbiting-a-distant-star

[ronin]

Accept the universe as it is or at present appears to be.

Throughly expect in 10 years time that something will have changed and a new assessment will be required. Equally expect that the reassesment will be more of a small modification to what we know rather then throw everything away and start again. Although in one or two aspects I could see it being a bigger change.

Newtons laws of gravity were OK for 300 years, then they sort of failed (Mercury) and Einstein presented his theory of Relativity that answered the situation better. Einsteins was 100 years ago, are we due a new or improved variant of that?

The one aspect is that there is likely no use in saying "This is how it is!"

It very likely is not. Assume nothing and expect to change whatever it is you think you understand.

Not sure where you are but if you can get to a talk by Dr Stuart Clark he will present a slightly different take on things. I assume that that was the talk he presented at the IAS a few weeks back. Will also say that if you attend a talk then do not presume that what is said is "absolute" many I have attended fall into 2 brackets: Presentation of the latest information with or without a theory, the other tend to be the presenters "pet" theory and may or may not have evidence to back them up.

[Ray02]

it just got more complicated with more unanswered questions im afraid LOL

http://www.sciencealert.com/scientists-can-t-explain-the-bizarre-mass-of-objects-orbiting-a-distant-star

Yeah... Its just the more you know the more you dont

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[Ray02]

Accept the universe as it is or at present appears to be.

Throughly expect in 10 years time that something will have changed and a new assessment will be required. Equally expect that the reassesment will be more of a small modification to what we know rather then throw everything away and start again. Although in one or two aspects I could see it being a bigger change.

Newtons laws of gravity were OK for 300 years, then they sort of failed (Mercury) and Einstein presented his theory of Relativity that answered the situation better. Einsteins was 100 years ago, are we due a new or improved variant of that?

The one aspect is that there is likely no use in saying "This is how it is!"

It very likely is not. Assume nothing and expect to change whatever it is you think you understand.

Not sure where you are but if you can get to a talk by Dr Stuart Clark he will present a slightly different take on things. I assume that that was the talk he presented at the IAS a few weeks back. Will also say that if you attend a talk then do not presume that what is said is "absolute" many I have attended fall into 2 brackets: Presentation of the latest information with or without a theory, the other tend to be the presenters "pet" theory and may or may not have evidence to back them up.

Yes i agree with that. Thanks for your opinion budd

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[Ray02]

I think we should just accept the universe as it is as Ronin said. Maybe in the near future there will be much more known than unknown. All we can do is study and try to understand

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[ollypenrice]

I'd want to have a care with a phrase like 'just theories.' There is no 'just' about theories. They may not last forever, they may be later rejected (rare) or generalized (more common) but they are highly evidence-based and have been rigorously scrutinized by the most able minds in the field. There is a huge difference between a theory and an hypothesis. An hypothesis is the starting point but the road to turning it into a theory is long and hard.

I would rather say that theories are models, the best we can make, and that that with luck they will go on getting better and better. Bad science teachers may tell their sudents that 'this is explanation the truth, is fact,' but only the bad ones would ever say such a thing. (I had plenty of bad ones...)

It's worth noting that Newton's gravity was replaced by Einstein's but that Newton himself, along with some of his contemporaries, knew that all was not well with his theory. Newton was troubled by the 'instantaneous action at a distance' that his theory seemed to require.

Olly

[Stub Mandrel]

Yeah... Its just the more you know the more you dont

You have taken the first step on the path to true wisdom, Grasshopper.

[michaelmorris]

I'll second Olly's comments about the dangers of the use of the phrase "just theories". 

The scientific method doesn't provide certainty about anything.   In science (as opposed to mathematics), you can't 'prove' anything.  The scientific method uses rigorous experimentation to provide evidence of the probability that a hypothesis is incorrect.  "Just a theory" could encompass speculation based purely on deductive reasoning - that isn't science.

[acey]

The predictions of quantum electrodynamics (QED) have been tested against experimental measurements (e.g. the electron anomalous magnetic dipole moment) and found to be accurate to within one part in a hundred million. Some day a better theory will come along - but it will have to be even more accurate than the 99.999999% accuracy of quantum electrodynamics. In 2010 a pair of aluminium ion clocks (accurate to about one second in 3.7 billion years) were used to demonstrate gravitational time dilation when one clock was about a foot higher off the ground than the other, thus verifying a prediction of general relativity (GR) to an accuracy comparable to that achieved for quantum electrodynamics. They may be "just" theories but it's a pretty impressive "just". A lot better than astrology or tea leaves, that's for sure. When you hear about possible new theories, they're competing for that tiny little corner that's beyond the current measurement limit of QED and GR. Or they're theories that don't make any predictions at all.

[ollypenrice]

The predictions of quantum electrodynamics (QED) have been tested against experimental measurements (e.g. the electron anomalous magnetic dipole moment) and found to be accurate to within one part in a hundred million. Some day a better theory will come along - but it will have to be even more accurate than the 99.999999% accuracy of quantum electrodynamics. In 2010 a pair of aluminium ion clocks (accurate to about one second in 3.7 billion years) were used to demonstrate gravitational time dilation when one clock was about a foot higher off the ground than the other, thus verifying a prediction of general relativity (GR) to an accuracy comparable to that achieved for quantum electrodynamics. They may be "just" theories but it's a pretty impressive "just". A lot better than astrology or tea leaves, that's for sure. When you hear about possible new theories, they're competing for that tiny little corner that's beyond the current measurement limit of QED and GR. Or they're theories that don't make any predictions at all.

That is truly astounding. I knew that the experiment had been performed but not at such a minute relative shift in distance from the earth's centre of gravity. Stunning.

However, while quantum theory has phenomenal predictive power it seems to have very little conceptually descriptive power. I wonder what you think about this?

Olly

[Ptarmigan]

However, while quantum theory has phenomenal predictive power it seems to have very little conceptually descriptive power. I wonder what you think about this?

That is 'just' a problem with our brains

mahatmacoat.

[Tiki]

In 2010 a pair of aluminium ion clocks (accurate to about one second in 3.7 billion years) were used to demonstrate gravitational time dilation when one clock was about a foot higher off the ground than the other, thus verifying a prediction of general relativity (GR) to an accuracy comparable to that achieved for quantum electrodynamics.

I'm not too sure of this, since the value of G is not known to a very high degree of precision (scarcely better than one part in a thousand). That a discernible difference in clock rates can be measured at a one foot difference in altitude is astonishing though.

That QED has so very little 'conceptually descriptive power' I feel is just the nature of the beast: a convenient rule which just happens to work. It would certainly be nice if some bright spark could come up with some meaningful physical motivation for the rules.

[acey]

I'm not too sure of this, since the value of G is not known to a very high degree of precision (scarcely better than one part in a thousand). That a discernible difference in clock rates can be measured at a one foot difference in altitude is astonishing though.

That QED has so very little 'conceptually descriptive power' I feel is just the nature of the beast: a convenient rule which just happens to work. It would certainly be nice if some bright spark could come up with some meaningful physical motivation for the rules.

Agreed, the clock experiment doesn't in fact verify GR to anything like the same level of precision as QED - but was pretty astonishing.

As to conceptual description, this has been a problem since the time of Maxwell - how do you find a "physical picture" for a theoretical prediction. I think in the end it shows that our ability to form physical pictures is limited by our reliance on our senses. Things break down at scales where our senses (and "common sense") no longer apply. Hence the "operational" approach - if the prediction is close enough then something must be right.

[Dave In Vermont]

I'll second Olly's comments about the dangers of the use of the phrase "just theories". 

The scientific method doesn't provide certainty about anything.   In science (as opposed to mathematics), you can't 'prove' anything.  The scientific method uses rigorous experimentation to provide evidence of the probability that a hypothesis is incorrect.  "Just a theory" could encompass speculation based purely on deductive reasoning - that isn't science.

Science uses verifiable data which stands up to being repeatable. Hence the word 'reseach' which, if you look at it, means to look again. And again. The result of the search being the same as the previous one.

Now where did I leave my Pu239.....?

Dave

[nameunknown]

However, while quantum theory has phenomenal predictive power it seems to have very little conceptually descriptive power. I wonder what you think about this?

Olly

Really? - as noted above, we have brains that are built for classical physics (will that tiger catch me or not, how far can I throw this rock) because something complex enough to think needs to be much, much bigger than the quantum scale and is made of stuff that isn't around until the universe has got very large and hence fairly cool. We are very good at this internal classical maths and only recently have been able to build robots that can, for eaxmple, walk on two legs - although I doubt they could play cricket. Our normal intuition doesn't do for - "mmmm... I wonder what her/his eigenvectors are like" or "hah! - there is an orthonormal basis hiding behind that bush". - so in QP you have to internalise the maths until it's (almost) a reflex - "i" isn't something Darwin equiped us for*.

But I'd not quite agree that QP isn't descriptive, like Einstein and Newton, QP is just a broader description of the approximation for big objects moving at slow speeds, but it explains very well why we don't fall through the floor (Pauli Exclusion Principle), how Neutron Stars and White Dwarfs work, why we have superconductors and semiconductors, black body radiation (light bulbs) and quite a few other "everyday" things. Fred Hoyle, now sadly only remembered for deriding the "Big Bang" and writing some SF, used QP to make a prediction about why the sun shines (late proved true!)....

So my view is that QP is descriptive - it's just that it describes things that were not that important to our monkey-brained ancestors for whom Schrodinger's Cat had sabre teeth and might or might not be waiting down the left or right hand path. If our ancestors had been molecule sized then our "senses" would be evolved for a QP landscape and we would be quite at home with the idea that we couldn't know both where we were and what we were doing, or that anything we interacted with behaved in an unpredicatable way, or that things seemed to appear and dissapper at random (quite unlike the "real" world!).

P

* well apart from one of the rarer giant tortoises on the Galapagos islands - Panzermaus Argandi - is so massive and slow that it needs to take shortcuts through the complex plane to get to the next cabbage before it wilts. While quite intelligent, they see naturalists as fast-moving short-lived particles and don't bother with conversation.

[ollypenrice]

However, while quantum theory has phenomenal predictive power it seems to have very little conceptually descriptive power. I wonder what you think about this?

Olly

Really? - as noted above, we have brains that are built for classical physics (will that tiger catch me or not, how far can I throw this rock) because something complex enough to think needs to be much, much bigger than the quantum scale and is made of stuff that isn't around until the universe has got very large and hence fairly cool. We are very good at this internal classical maths and only recently have been able to build robots that can, for eaxmple, walk on two legs - although I doubt they could play cricket. Our normal intuition doesn't do for - "mmmm... I wonder what her/his eigenvectors are like" or "hah! - there is an orthonormal basis hiding behind that bush". - so in QP you have to internalise the maths until it's (almost) a reflex - "i" isn't something Darwin equiped us for*.

But I'd not quite agree that QP isn't descriptive, like Einstein and Newton, QP is just a broader description of the approximation for big objects moving at slow speeds, but it explains very well why we don't fall through the floor (Pauli Exclusion Principle), how Neutron Stars and White Dwarfs work, why we have superconductors and semiconductors, black body radiation (light bulbs) and quite a few other "everyday" things. Fred Hoyle, now sadly only remembered for deriding the "Big Bang" and writing some SF, used QP to make a prediction about why the sun shines (late proved true!)....

So my view is that QP is descriptive - it's just that it describes things that were not that important to our monkey-brained ancestors for whom Schrodinger's Cat had sabre teeth and might or might not be waiting down the left or right hand path. If our ancestors had been molecule sized then our "senses" would be evolved for a QP landscape and we would be quite at home with the idea that we couldn't know both where we were and what we were doing, or that anything we interacted with behaved in an unpredicatable way, or that things seemed to appear and dissapper at random (quite unlike the "real" world!).

P

* well apart from one of the rarer giant tortoises on the Galapagos islands - Panzermaus Argandi - is so massive and slow that it needs to take shortcuts through the complex plane to get to the next cabbage before it wilts. While quite intelligent, they see naturalists as fast-moving short-lived particles and don't bother with conversation.

I'm not deriding quantum theory but I'm not yet ready to accept the idea that a conceptually satisfying description of the sub atomic world could not be formulated if someone had the right insights. Language is powerful and metaphor constitutes a large part of its power. I think it might one day happen. On the other hand, maybe not. Maybe I'm asking someone to telll me what the inside of an atom 'looks like' and this may be as pointles as asking what a black hole looks like. After all, what does Beethoven's Fifth look like?

Olly

[m1dlj]

I'm not deriding quantum theory but I'm not yet ready to accept the idea that a conceptually satisfying description of the sub atomic world could not be formulated if someone had the right insights. Language is powerful and metaphor constitutes a large part of its power. I think it might one day happen. On the other hand, maybe not. Maybe I'm asking someone to telll me what the inside of an atom 'looks like' and this may be as pointles as asking what a black hole looks like. After all, what does Beethoven's Fifth look like?

Olly

Many misconceptions in physics and cosmology originate from well-meaning attempts at 'conceptually satisfying descriptions'.

Language and metaphor also have the power to amplify small misconceptions, creating established delusions.

A complete and penetrable description of QT (as opposed to another misleading analogy) would of course be most welcome, but I'm not as optimistic.

Ray

(What does Beethoven's Fifth look like? Best ask a synesthete.) 

[ollypenrice]

Many misconceptions in physics and cosmology originate from well-meaning attempts at 'conceptually satisfying descriptions'.

Language and metaphor also have the power to amplify small misconceptions, creating established delusions.

A complete and penetrable description of QT (as opposed to another misleading analogy) would of course be most welcome, but I'm not as optimistic.

Ray

(What does Beethoven's Fifth look like? Best ask a synesthete.) 

All fair points. However, metaphor in language  and analogy are different things. It isn't another analogy that I'm after. Metaphor extends the range of a word without necessarily having recourse to analogy. A 'top' sportsman is a phrase which is metaphorical but not allegorical, I would say. And you can invent new words when new ideas require them.

Even allegory is not all bad. Maxwell's equations were born from an attempt to describe mathematically an imaginary machine which he began by envisaging.

I suppose I'm just a bit suspicious of anything which can only be desribed mathematically and which is purely predictive. A purely mathematical understanding strikes me as incomplete and as someone fascinated and enthralled by language I'm rarely ready to accept that anything of which our brains are capable is likely to be truly beyond its range. I think that, one day, it might be possible to resolve wave and particle into a single and more meaningful phrase.

In any discussion about the nature of theory in science I think we should also look at string theory which is sliding into new (and unsound?) territory. Without having made a single prediction it is passing into some kind of orthodoxy in a way which has never been allowed to happen before. How has this been allowed to happen? Is it because of an addiction to the kind of mathematical power unleashed by computers? I don't know, but I can't think of anything comparable since the start of the scientific revolution.

Olly

[nameunknown]

Perhaps Beethoven's Vth looks like two fingers raised in the air, or the Morse code for "V": "di-di-di-dahhh". A "metaphor" is a wheelbarrow in Greece and "analogy" may well be illegal there - I've been reading books on quantum mechanics for years (Suskind is quite good - as are his "Stamford" videos) but is it really more than cold maths?? Does any of this provide an objective reality which smacks one in the face and says "thus is what is" - nope. I sometimes wonder which would be better:

• an astounding insight into Newtonian, Einsteinien, Feymanian physics... or,
• a lazy weekend with them all down the pub and between times at a BBQ (with clear nights at the 'scope as well)

I rather think (for me) the latter would be more rewarding than the former: a journey with interesting companions (as on SGL) can be better than the destination, explanation, etc...

P

[acey]

What does Beethoven's Fifth look like?

[nameunknown]

fair point..