https://youtu.be/liXOb5JXg6w
Thanks for posting this. There is always something new, and often mysterious. The idea that the Cosmological Constant (it is a simple addition to the neutral GR equation of a simple number) explains anything, even Dark Energy ... is a stretch. Pythagoras wouldn't have made such a simple assumption, he at least understood harmonic progression ;-) Certainly in the early universe, there was mostly hydrogen and a small percentage of helium. Just explaining what happens after that, is a big job, that is constantly being improved today. Like the notion of super giant stars in the early galaxies, that became congregated into giant black holes/quasars ... and produced most of the early heavy elements ... is pretty new. Early on, there weren't enough heavy elements to form an Earth-like planet.
We have evolved from deus ex machina ... to cosmologist ex machina. With equations ... like good Pythagoreans.
You guys just don't get that this universe is just a corrupted simulation of another universe.
The video is no longer available.
Quote from: CrucifyCindy on September 17, 2015, 12:32:50 AM
You guys just don't get that this universe is just a corrupted simulation of another universe.
Are we a lexx fan?
Quote from: Baruch on September 16, 2015, 07:42:12 PM
The idea that the Cosmological Constant (it is a simple addition to the neutral GR equation of a simple number) explains anything, even Dark Energy ... is a stretch.
A stretch?!? Not really. The cosmological constant (cc)
is energy density. So it is not a stretch that it would play a role in explaining
Dark Energy. Whether the cc gives the complete story is another issue as we don't know how good GR is in explaining the full story of our universe.
It seems like I read some place that even Einstein had reservations about the addition of the cosmological constant to GR.
When Einstein published his GR (1915), the general thinking at the time was that the universe was stable and stationary. In order to fit his theory with that, he needed to have the cosmological constant (cc) to take on some value. Ten years later Hubble had discovered that the universe was expanding, so Einstein's fixing of the cc was no longer valid. However, when it was discovered in the 1990's that the universe was actually accelerating, the cc had to be revived to explain this new data.
It is currently not known what either dark energy or dark matter are. The terms them selves are merely placeholders. And together
they make up ninety six per cent of the observable Universe and there is still very much left to discover. And a Theory Of Quantum
Gravity has to be discovered which will cancel the famous incompatibility between Quantum Mechanics and General Relativity. And
trying to establish what happened before the Big Bang since it is far more probable that it was simply the beginning of local cosmic
expansion as opposed to the beginning of absolutely everything. The twin discoveries of Q M and G R in the twentieth century were
the pinnacle of physics in that period. Although there is still far more to be achieved before a truly fundamental and comprehensive
understanding of observable phenomena can be established. Assuming of course that that is actually possible. Given how science is
an inductive discipline that relies upon evidence to validate its hypotheses I am sceptical of this. For it is an eternally self correcting
system. So there is never a point at which scientific knowledge is therefore absolute. For there will always be gaps in understanding
Quote from: surreptitious57 on September 19, 2015, 03:47:56 AM
Given how science is an inductive discipline that relies upon evidence to validate its hypotheses I am sceptical of this. For it is an eternally self correcting
system. So there is never a point at which scientific knowledge is therefore absolute. For there will always be gaps in understanding
You make it sound as if that was a bad thing when in reality it is a good thing that science is a method that allows self-correction, as oppose to religious belief which claims to have monopoly on truth.
Well as space expands, anything to is connected to space itself is likely to have it bonds stretched or even broken, obviously this video was connected to YouTube via one of these bonds, which have now been severed. :)
I wonder whether the accelerating expansion of space-time might become so great that it would eventually rip virtual particles apart so fast as to keep them from ever annihilating? If so, what would be the result?
Quote from: Unbeliever on September 23, 2015, 05:26:50 PM
I wonder whether the accelerating expansion of space-time might become so great that it would eventually rip virtual particles apart so fast as to keep them from ever annihilating? If so, what would be the result?
That would be unlikely. Dark Energy, responsible for this acceleration, is far too weak. If you could gather all the energy of Dark Energy from here to I billion light-years away from our planet, you would have enough energy to light a lightbulb.
OK, but the density of dark energy stays the same, while the matter/radiation density decreases. So the ratio will eventually become so great that it's small energy content "now" may not matter. I'm talking several trillion years in the future, by which time the "heat death" may have occurred.
Quote from: Unbeliever on September 23, 2015, 05:41:39 PM
OK, but the density of dark energy stays the same, while the matter/radiation density decreases. So the ratio will eventually become so great that it's small energy content "now" may not matter. I'm talking several trillion years in the future, by which time the "heat death" may have occurred.
Yes, but in a trillion years, the earth won't exist. So who is going to witness this ripping apart... oh wait, God...:lol_hitting:
So the Big Rip is certainly a possibility as the very fabric of spacetime is stretched apart by cosmic expansion whilst the
Universe carries on expanding beyond light speed. Although this is not the most probable scenario. That was an eternal
Universe with alternating Big Bangs and Big Crunches. However the observation of gravitational waves occurring during
inflation has since invalidated this. These are quantum fluctuations happening in the fabric of spacetime. How it shall all
end or if it will end at all while very interesting is entirely academic. Since homo sapiens will be extinct long before then
Quote from: surreptitious57 on September 24, 2015, 02:48:06 AM
So the Big Rip is certainly a possibility as the very fabric of spacetime is stretched apart by cosmic expansion whilst the
Universe carries on expanding beyond light speed. Although this is not the most probable scenario. That was an eternal
Universe with alternating Big Bangs and Big Crunches. However the observation of gravitational waves occurring during
inflation has since invalidated this. These are quantum fluctuations happening in the fabric of spacetime. How it shall all
end or if it will end at all while very interesting is entirely academic. Since homo sapiens will be extinct long before then
There are many cosmological models at play. The mainstream one is the Big Bang theory. What we really don't know is: what happened at very small scale since we don't have a quantum theory of gravity; will the universe continue to accelerate indefinitely. Of course there are other questions, more on the fringe of speculation: do we live in a multiverse and are there extra dimensions. So yeah, those questions are academic. But physicists are driven by the actual situation that you one theory, general relativity, to explain large distances, and a totally different theory, quantum mechanics, to explain the very small distances, and the consensus is that there should be one theory - this is reminiscent to pre-Newton times when people believe there were two separate kinds of realm: the terrestrial and the heavens.
Here are some good replacement videos:
https://www.youtube.com/watch?v=5LW_2J2qs0Y
https://www.youtube.com/watch?v=CfrPbjSYOus
https://www.youtube.com/watch?v=TStaWXBHbIo
(http://i243.photobucket.com/albums/ff277/josephpalazzo/darkmatter.jpg) (http://s243.photobucket.com/user/josephpalazzo/media/darkmatter.jpg.html)
So that is how Munch's friends get pumped ... the space-time inside their biceps etc is expanding? ;-))
Quote from: Baruch on September 27, 2015, 05:49:22 PM
So that is how Munch's friends get pumped ... the space-time inside their biceps etc is expanding? ;-))
You've got that wrong: Dark Energy is for expanding, but
Dark Matter is for clumping up.
Quote from: surreptitious57 on September 24, 2015, 02:48:06 AM
How it shall all
end or if it will end at all while very interesting is entirely academic. Since homo sapiens will be extinct long before then
Well, Homo Sapiens wasn't here for most of the past history of the universe, but we still find it very interesting. So just because we won't be around to witness the future of the universe doesn't mean we don't find that interesting, as well. Why does our presence or absence mean anything at all where such questions are in play?
Per the Easter Egg at the end of the postlude ... humans evolve into Vorlons, and so exist for a very long time.
Our presence in the Universe matters to us both for reasons of self preservation and because we
can actually investigate it also. Though as for it itself it does not require us at all. It is simply the
sum of all its parts and so then from a purely materialistic perspective it makes no difference if it
supports intelligent life or not. Because only intelligent life could actually be concerned about that
For the Universe is incapable of such abstract thinking. Despite us actually being part of it as such
I've come to think that it may be easier to consider that the cosmic density is decreasing, instead of the cosmos expanding. We still don't know for sure that the universe is absolutely flat. It may be closed on itself on a truly humongous scale. Our ability to measure the flatness isn't perfect, so it could still be curved on a scale we can't yet fathom.
Quote from: Unbeliever on October 23, 2015, 07:31:38 PM
I've come to think that it may be easier to consider that the cosmic density is decreasing, instead of the cosmos expanding. We still don't know for sure that the universe is absolutely flat. It may be closed on itself on a truly humongous scale. Our ability to measure the flatness isn't perfect, so it could still be curved on a scale we can't yet fathom.
Present theory considers that Dark Energy Density (DED) is a constant in the Einstein's Field Equations (EFE). So as the universe expands, the Dark Energy increases with the increasing volume. Nevertheless the EFE does not exclude that the DED could be varying in time. This would allow a universe to expand, then contract, then expand and so on. Pretty much like the human heart. In such a scenario, the universe is eternal as it has no beginning, no ending, and no Big Bang to start it all.
A very recent, not too technical lecture ...
https://www.youtube.com/watch?v=f1x9lgX8GaE&spfreload=10
I met Neil once at a seminar. He's a charming fellow. But he has a naive view of Relativity. He believes it's the most beautiful and self-consistent theory. I pointed out to him that Einstein made a leap of faith in his derivation - I have a blog on that (http://soi.blogspot.ca/2014/01/the-essential-general-relativity.html). We ended up to agree to disagree.
Quote from: josephpalazzo on October 25, 2015, 07:51:53 AM
I met Neil once at a seminar. He's a charming fellow. But he has a naive view of Relativity. He believes it's the most beautiful and self-consistent theory. I pointed out to him that Einstein made a leap of faith in his derivation - I have a blog on that (http://soi.blogspot.ca/2014/01/the-essential-general-relativity.html). We ended up to agree to disagree.
Einstein had very good physical intuition ... and was lucky. Faith had nothing to do with it. His personal overweening self confidence helped him, but it turned off the people around him. Only another completely overweening person like Bohr could stand up to him.
Don't relativists and QM-ists never mix well? This is a continuation of the one on one debates between Einstein and Bohr. The QM-ists won that round, and I suspect they will again ;-) See as per a recent good video on Einstein ... he had a neo-Kantian prejudice, not really a Machian ... and this happened to work in his case, but only at the beginning. Afterward it was a hindrance. On the other hand it is MHO that the "shut up and calculate" QM-ists are ignoramuses, or savants, not real physicists. Feynman was of this ilk. Ask Bethe what Feynman was like as a grad student. Einstein was the opposite, he was actually bad at math, and needed constant assistance.
Quote from: Baruch on October 25, 2015, 11:03:33 AM
Einstein had very good physical intuition ... and was lucky. Faith had nothing to do with it. His personal overweening self confidence helped him, but it turned off the people around him. Only another completely overweening person like Bohr could stand up to him.
Don't relativists and QM-ists never mix well? This is a continuation of the one on one debates between Einstein and Bohr. The QM-ists won that round, and I suspect they will again ;-) See as per a recent good video on Einstein ... he had a neo-Kantian prejudice, not really a Machian ... and this happened to work in his case, but only at the beginning. Afterward it was a hindrance. On the other hand it is MHO that the "shut up and calculate" QM-ists are ignoramuses, or savants, not real physicists. Feynman was of this ilk. Ask Bethe what Feynman was like as a grad student. Einstein was the opposite, he was actually bad at math, and needed constant assistance.
The irony about Einstein is that I think he never really understood QM, though he contributed immensely, and his misunderstanding is not out of the ordinary as most QM pioneers didn't understand it either (it took a good understanding of QFT to see where QM fits in the grander scheme of things, circa 1970's). Nevertheless, Einstein's misunderstanding spurred on a whole cottage industry (EPR, Bell's theorem, and the never ending hopeless search for nonlocality).
BTW, my PhD thesis was based on Bethe's groundbreaking paper on the reference spectum for nuclear matter.
Quote from: josephpalazzo on October 25, 2015, 11:15:23 AM
The irony about Einstein is that I think he never really understood QM, though he contributed immensely, and his misunderstanding is not out of the ordinary as most QM pioneers didn't understand it either (it took a good understanding of QFT to see where QM fits in the grander scheme of things, circa 1970's). Nevertheless, Einstein's misunderstanding spurred on a whole cottage industry (EPR, Bell's theorem, and the never ending hopeless search for nonlocality).
BTW, my PhD thesis was based on Bethe's groundbreaking paper on the reference spectum for nuclear matter.
OK ... give us a five sentence summary of your PhD thesis ;-) Someone said, if you can't explain something to an ordinary person in one minute ... then you don't really understand it yourself!
Yes, they were all classical physicists groping about in a new world. It seems only Dirac understood, but nobody could understand Dirac ;-) See the anecdote in this lecture, where Dirac meets Feynman as a grad student. Not that I don't admire Feynman in his own way ... but there is a difference between an arithmetical savant and a number theorist.
Quote from: Baruch on October 25, 2015, 11:24:48 AM
OK ... give us a five sentence summary of your PhD thesis ;-) Someone said, if you can't explain something to an ordinary person in one minute ... then you don't really understand it yourself!
I'll just give you the title: PERTURBATION THEORY WITH NON-LOCAL POTENTIALS IN NUCLEAR MATTER.
Bethe's paper is listed 9 in my bibliography.
H.A. Bethe, B.H. Brandow, and A.G. Petschek, Phys. Rev. 129,293 (1964)
Quote from: josephpalazzo on October 25, 2015, 11:46:44 AM
I'll just give you the title: PERTURBATION THEORY WITH NON-LOCAL POTENTIALS IN NUCLEAR MATTER.
Bethe's paper is listed 9 in my bibliography.
H.A. Bethe, B.H. Brandow, and A.G. Petschek, Phys. Rev. 129,293 (1964)
But you poo-poo non-locality now? Or do you simply mean "non-central forces" which would be easy to imagine but hard to calculate. Non-locality on a fundamental view of course is different than just something complicated that jumps out of a Lagrangian and bites one ;-)
Quote from: Baruch on October 25, 2015, 12:13:52 PM
But you poo-poo non-locality now? Or do you simply mean "non-central forces" which would be easy to imagine but hard to calculate. Non-locality on a fundamental view of course is different than just something complicated that jumps out of a Lagrangian and bites one ;-)
Yep, non-local potentials in my thesis are in fact velocity dependent, like the magnetic field. It's not in the sense of nonlocality in QM, where the interaction between two particles would depend on the rest of the cosmos with a mysterious spooky action at a distance.
Quote from: josephpalazzo on October 25, 2015, 12:20:23 PM
Yep, non-local potentials in my thesis are in fact velocity dependent, like the magnetic field. It's not in the sense of nonlocality in QM, where the interaction between two particles would depend on the rest of the cosmos with a mysterious spooky action at a distance.
See ... I do understand a little ... I was just skimming in my "Classical Mechanics" 2nd Ed by Corben ... but then that would be telling ;-)
Quote from: Baruch on October 25, 2015, 12:35:32 PM
See ... I do understand a little ... I was just skimming in my "Classical Mechanics" 2nd Ed by Corben ... but then that would be telling ;-)
Be careful, a little knowledge can be dangerous... old proverb.
Quote from: josephpalazzo on October 25, 2015, 12:53:39 PM
Be careful, a little knowledge can be dangerous... old proverb.
I like being dangerous ;-) And all of us, only have a little knowledge, even professors ;-)
Quote from: Baruch on October 25, 2015, 01:01:17 PM
... And all of us, only have a little knowledge, even professors ;-)
You fit well within the American anti-intellectual culture and the dumbing down of America. You must have been cheering when George W was elected.
Quote from: josephpalazzo on October 25, 2015, 01:19:29 PM
You fit well within the American anti-intellectual culture and the dumbing down of America. You must have been cheering when George W was elected.
HAhahah ... such good trolling ... bravo. No that isn't what happened, thanks to difficulties of life, I grew up and got over my own intellect. My heart is much more important now.
Quote from: Baruch on October 25, 2015, 03:44:26 PM
HAhahah ... such good trolling ... bravo. No that isn't what happened, thanks to difficulties of life, I grew up and got over my own intellect. My heart is much more important now.
Your answer is typical of a theist: in you heart of heart, you know it's true... That's the very reason why the world is such a fucking mess. You must feel good to be on the same side of the Christian Right and their righteous arrogant posturing.
Quote from: josephpalazzo on October 25, 2015, 03:54:23 PM
Your answer is typical of a theist: in you heart of heart, you know it's true... That's the very reason why the world is such a fucking mess. You must feel good to be on the same side of the Christian Right and their righteous arrogant posturing.
High IQ & low EQ or ... I don't claim to have both, but I know which one is better.
Quote from: Baruch
Someone said, if you can't explain something to an ordinary person in one minute ... then you don't really understand it yourself!
Bah. That phrase is a good advice to try to always have a high level understanding of what you do.
To actually believe it is practically feasible is to severily understimate the problem of communication, pedagogy and the complexy of the matter.
https://www.youtube.com/watch?v=xog7gjwfVqk
Pr126 ... this particular documentary was the original post, but was lost in a Youtube censorship. Thanks for reposting it ... it contrasts well with the other recent similar documentaries.
Quote from: Baruch on October 25, 2015, 06:07:11 PM
High IQ & low EQ or ... I don't claim to have both, but I know which one is better.
You've just confirmed my post: in you heart of heart, you know it's true. You're no different than those guys who flew planes into buildings.
Quote from: josephpalazzo on October 26, 2015, 07:56:36 AM
You've just confirmed my post: in you heart of heart, you know it's true. You're no different than those guys who flew planes into buildings.
Just a blog post but ...
http://www.entrepreneur.com/article/248329
Are you MENSA?
Quote from: Baruch on October 26, 2015, 12:40:04 PM
Just a blog post but ...
http://www.entrepreneur.com/article/248329 (http://www.entrepreneur.com/article/248329)
The title of your article is: How Important Is Emotional Intelligence to Success in Business?
So which business did you build?
Quote from: josephpalazzo on October 26, 2015, 12:49:36 PM
The title of your article is: How Important Is Emotional Intelligence to Success in Business?
So which business did you build?
It isn't about me ... it is about you ... and you still don't get it ;-) I am not making any claims for myself ... because I have never respected "authority".
Einstein claimed that the single greatest mistake of his career was the introduction of the cosmological constant. However
that fades into insignificance when compared to his absolute refusal to accept quantum mechanics because it was counter
intuitive to his notion of an ordered universe. And so it is an irony of unbelievable magnitude that he produced one of the
twin pillars of twentieth century physics that itself is counter intuitive yet saw it as totally acceptable whilst then rejecting
the other pillar entirely. This was totally new territory of course but others like Heisenberg and Schrodinger and Bohr and
Dirac accepted it even if they did not always understand it. Now by complete contrast Einstein rejected it on philosophical
grounds which is not how a scientist should be doing science. And so Feynman was absolutely right when he said that the
only thing that matters is evidence. So anything which contradicts that has to be rejected even if it is so counter intuitive
it makes no sense. For what ultimately matters is if something is objectively true not whether or not it can be understood
Quote from: surreptitious57 on October 31, 2015, 12:34:18 PM
Einstein claimed that the single greatest mistake of his career was the introduction of the cosmological constant. However
that fades into insignificance when compared to his absolute refusal to accept quantum mechanics because it was counter
intuitive to his notion of an ordered universe. And so it is an irony of unbelievable magnitude that he produced one of the
twin pillars of twentieth century physics that itself is counter intuitive yet saw it as totally acceptable whilst then rejecting
the other pillar entirely. This was totally new territory of course but others like Heisenberg and Schrodinger and Bohr and
Dirac accepted it even if they did not always understand it. Now by complete contrast Einstein rejected it on philosophical
grounds which is not how a scientist should be doing science. And so Feynman was absolutely right when he said that the
only thing that matters is evidence. So anything which contradicts that has to be rejected even if it is so counter intuitive
it makes no sense. For what ultimately matters is if something is objectively true not whether or not it can be understood
Just a caution: Einstein did not reject QM as a scientific theory, what he rejected was the prevailing
interpretation.
Quote from: josephpalazzo on October 31, 2015, 01:04:34 PM
Just a caution: Einstein did not reject QM as a scientific theory, what he rejected was the prevailing interpretation.
Maybe Einstein just didn't like a cheesy danish ... like Bohr ;-) The book, Thirty Years That Shook Physics ... they pointed out that Bohr's laboratory was financed by a beer brewery. Maybe Bohr sampled the production too much? He is the father of the "shut up and just calculate" school of physics. If you study Einstein as a philosopher ... he was neo-Kantian, not really Machian (who was a pure empiricist). Einstein's thinking was eclectic, he used whatever philosophy suited him at the time. Bohr was like some here ... philosophy agnostic. If you have the right equation kabuki (original Bohr atom) then all things are good. But it took DeBroglie to explain why the Bohr atom worked ... and Schrodinger to perfect it. Heisenberg on the other hand was like Bohr, but a better mathematician. To my taste, QM circa 1930 does seem semi-empirical ... as it did to Einstein (and Planck, DeBroglie, and Schrodinger). But Einstein's intuition ran out of gas around 1924 ... he had gone from being the rebel who challenged the authorities, to being an authority himself! Relativistic QM started prematurely with Schrodinger (early Klein-Gordon), established by Dirac, perfected by Feynman, Schwinger and Tomonaga. Physics today is running on fumes from 1950 forward, especially from 1983 onward. But nobody has seriously eliminated the Copenhagen (Bohr) interpretation.
If you look at physics around 1900 ... there were three schools. Newtonian mechanical, Maxwell field theory, Boltzmann thermodynamics (aka energeticism). The Newtonian was maintained for ordinary engineering (though Poincare had pointed out other celestial mechanical problems other than the orbit of Mercury, that ultimately presaged Chaos theory). Maxwell field theory led to early electronics. Statistical energeticism led to QM ... first with Planck and Einstein. And QM led to modern electronics. With few exceptions, relativity theory has had little practical impact aside from GPS. Maxwell field theory, while perfected by SR, provided us with radio and radar. Einstein't corollary to Planck's work, was more crucial, though he rated it little compared to relativity theory ... and that is what he got the Nobel for. As an engineering student, I of course had to study the practical side of all three positions ... the more esoteric theoretical and experimental ... had little impact on my education ... unless I had shifted from engineering to physics in grad school. As it turned out, I went computer science instead.
The Copenhagen interpretation may not have been eliminated but it is by no means universal
Since there are alternatives to it that have support within the physics community such as the
the many worlds interpretation and string theory. These are the serious rivals to Copenhagen
There are also physicists who do not support any of these so nothing is established right now
Quote from: surreptitious57 on October 31, 2015, 05:31:43 PM
The Copenhagen interpretation may not have been eliminated but it is by no means universal
Since there are alternatives to it that have support within the physics community such as the
the many worlds interpretation and string theory. These are the serious rivals to Copenhagen
There are also physicists who do not support any of these so nothing is established right now
The sticky point about those who are still "intrigued" about QM often haven't studied QFT. QM is like getting a small sandwich with the crust cut off that people used as an appetizer, but unfortunately some think it's the main course. Those who have moved on to QFT find the discussion about interpretations of QM quaint and frankly obsolete. I feel sad for those who are still cranking papers after papers- perhaps to justify their tenure - on this subject, wondering where's the spooky action at a distance and the collapse of the wave function, and so on, and are still mesmerized about quantum "weirdness". Of course, there are people, like Michio Kaku, who are banking on continuing to have this weird stuff alive in order to fill auditoriums and get a hefty speaker's fee.
Quote from: josephpalazzo on October 31, 2015, 06:37:18 PM
The sticky point about those who are still "intrigued" about QM often haven't studied QFT. QM is like getting a small sandwich with the crust cut off that people used as an appetizer, but unfortunately some think it's the main course. Those who have moved on to QFT find the discussion about interpretations of QM quaint and frankly obsolete. I feel sad for those who are still cranking papers after papers- perhaps to justify their tenure - on this subject, wondering where's the spooky action at a distance and the collapse of the wave function, and so on, and are still mesmerized about quantum "weirdness". Of course, there are people, like Michio Kaku, who are banking on continuing to have this weird stuff alive in order to fill auditoriums and get a hefty speaker's fee.
While low energy QM might be quaint ... I don't think that high energy QM aka QFT is free of interpretation. Brian Greene is a stringier version of Michio Kaku IMHO. Popularization of science is always suspect to me. So it is a gambit ... try to deal with interpretation in a perhaps easier but limited situation, or go whole hog and deal with interpretation there. In the case of Einstein, he had to develop SR first, then GR ... not GR and then derive SR from that. But it would be astounding in some parallel universe if that is what happened there. That Einstein would have a very enlarged cranium compared to the one in our universe, and maybe an even fuzzier head of hair ;-)