The Science Thread here

reply to post by Semicollegiate

Here is a Yale profesor explaining it to Chemistry Freshmen, using the analogy of Chladni figures, which are based on sound waves, but the electrons also have wave functions, hence the analogy. Like any analogy, it has limitations, but for someone who just wants a simple idea to compare electron orbitals to, I think it might help. Apparently so does this Yale professor since he teaches it.

9. Chladni Figures and One-Electron Atoms


Here's a screencap from 23:31 in the video mentioning the analogy:


The Greek letter refers to wave function.

The professor makes two of the chladni patterns in row 2 of this graphic in his demonstration:


If you can figure out how and why those Chladni patterns appear, you might gain some insights into electron orbitals, which of course look different because they are 3D instead of 2D, but it's just an analogy.

reply to post by Arbitrageur


Wow, as I suppose one would assume, the Yale undergraduate is a about one year ahead of the undergrads I would have studied with. They know first semester calculus at the very least. Chemistry has filled out quite a bit if it can describe chemical bonds in realtime as they are made or broken.

Do you know in what way the Hydrogen nucleus, a single proton, would fluctuate or vary as it simply existed at constant velocity? Does it throb or tumble on its axis or something?

Originally posted by Semicollegiate
Wow, as I suppose one would assume, the Yale undergraduates a about one year ahead of the undergrads I would have studied with. They know first semester calculus at the very least.

I don't assume they know calculus. Less than 20% had taken differential equations when he asked about that. I can't comment on what my school taught in Chemistry 101. I skipped that course in college because my advisor said it would be a waste of time for me based on my placement scores which met the prerequisite requirement for the more advanced courses. He thought I learned it all in high school, but I never saw anything like that Chladni pattern demonstration related to electron orbitals in high school. I don't know how widespread that teaching is in Chemistry 101 courses, or if it's something unique to Yale.

Originally posted by Semicollegiate
Do you know in what way the Hydrogen nucleus, a single proton, would fluctuate or vary as it simply existed at constant velocity? Does it throb or tumble on its axis or something?

I saw a cool animation of a proton presented by Lawrence Krauss. He said the proton gets 10% of its mass from the 3 quarks and the other 90% is in flux and shows a video of what scientists imagine the flux looks like, at 34 minutes in this video:


He says that was first presented in 2004 in Stockholm. I knew a lot of what he talked about in that video, but that animation of the proton was one of the new things I learned. I had never seen that animation before.

reply to post by Semicollegiate



Thanks but I was more so asking; The atom as a stable entity exists, im asking what causes what to be like what.

Does the nucleus cause the electron to do what it does in the atom, or does the electrons inherent nature cause it to behave the way it does when becoming trapped in an atom, does the space around an atom cause the electron once close to the nucleus to behave as it is witnessed, does the space inside the atom cause the electron to behave as it does, or is it a combination of all these things, that create the perfect physical balance, that is an atom?

Originally posted by Phage
reply to post by Moduli

 

Is string theory actually a theory? My impression is that it is more of a math construct.
Does it make testable predictions? Have any of those predictions been demonstrated?

According to author-physicist Brian Greene, string theory can predict the amount of dark energy in our universe. In some cases, we don't have the technology yet to test string theory predictions.

This also happened with some of Einstein's theories, like time dilation. Only when we had atomic clocks and put them on airplanes in 1971, did we directly see the effect.

thinkjustdoit.blogspot.ca...

Originally posted by ionwind
According to author-physicist Brian Greene, string theory can predict the amount of dark energy in our universe. In some cases, we don't have the technology yet to test string theory predictions.

If that was true, then the discovery of dark energy in 1998 shouldn't have been such a surprise and would have been a huge win for string theory, confirming the prediction. That didn't happen. I don't believe Brian Greene. Predicting it after it's already discovered, isn't a prediction.

I think his presentation is not much more than hypothesis, since there's little evidence. That doesn't mean it's wrong, or that string theory is wrong either as the blog you linked to says, but it could be just as likely that someone else's hypothesis turns out to be right. We won't know until there is evidence to support the hypotheses.

Some of the things Greene talks about in the presentation you linked fall in the realm of things like "how many angels can dance on the head of a pin?"

Originally posted by Arbitrageur

Originally posted by ionwind
According to author-physicist Brian Greene, string theory can predict the amount of dark energy in our universe. In some cases, we don't have the technology yet to test string theory predictions.

If that was true, then the discovery of dark energy in 1998 shouldn't have been such a surprise and would have been a huge win for string theory, confirming the prediction. That didn't happen. I don't believe Brian Greene. Predicting it after it's already discovered, isn't a prediction.

I think his presentation is not much more than hypothesis, since there's little evidence. That doesn't mean it's wrong, or that string theory is wrong either as the blog you linked to says, but it could be just as likely that someone else's hypothesis turns out to be right. We won't know until there is evidence to support the hypotheses.

Some of the things Greene talks about in the presentation you linked fall in the realm of things like "how many angels can dance on the head of a pin?"

That may be true, but he says he can predict the amount of dark energy in our universe , not just that it exists. It took 64 (1971-1907) years to empirically prove Einstein's time dilation effect, so may have to wait a bit.

Another area physicists are trying to make predictions using string theory involves quantum entanglement:

“If experiments prove that our predictions about quantum entanglement are correct, this will demonstrate that string theory ‘works’ to predict the behavior of entangled quantum systems,” said Professor Mike Duff, lead author of the study.

www.universetoday.com...

But I think string theory is really a paradigm shift. It can be used to create large scale cosmological models as well as describe matter and energy at the quantum level. There really isn't anything better right now. If it's discarded, so be it. If you can come up with something better, you'll probably win a Nobel prize.

Originally posted by ionwind

That may be true, but he says he can predict the amount of dark energy in our universe , not just that it exists. It took 64 (1971-1907) years to empirically prove Einstein's time dilation effect, so may have to wait a bit.

Greene says at time index 16:20 in this 2010 debate with Lawrence Krauss that

"If you're asking me, do I believe in string theory, the answer is 'no'"

He says that because it hasn't been experimentally confirmed, which he admits is necessary to give the idea scientific validity. He's the scientist arguing IN FAVOR of string theory. His opponent, Lawrence Krauss is more skeptical and you can hear some of his ideas if you want to listen...he specifically denies that string theory predicts the amount of dark energy:

www.federicopistono.org...

Lawrence Krauss and Brian Greene, two world-renowned physicists, square off in a spirited debate and discussion moderated by noted cosmologist Michael Turner. Greene's research focuses on superstring theory, which proposes a quantum theory of gravity as well as a unified theory of all forces and matter. This requires that the universe have 10 or 11 dimensions, not just the 4 we're aware of.

Krauss works at the boundary of particle physics and astrophysics, cosmology, and general relativity. His research deals with black holes, the very early universe, the future of the universe, dark matter, and dark energy. He is sceptical about string theory because it has yet to make a prediction that can be verified by experiment and has not solved any major physical puzzles about nature, including why the expansion of the universe is speeding up, the most profound question of our time.

Note the last sentence is a reference to dark energy, which is a direct contradiction to Greene's claim, isn't it?

reply to post by Arbitrageur


lawerence krauss is skeptical? That guy is a joke, hes the one with all the lectures about "a universe from nothing".

reply to post by ImaFungi

In the early 1900s, physicists thought of a static and eternal universe, which is why Albert Einstein developed the cosmological constant...a repulsive force to counteract gravity and explain why gravity hasn't pulled everything together.

Once Einstein found out the universe was expanding, the expansion explained why gravity hadn't collapsed the universe, so he thought it unnecessary.

But the expansion implies some kind of beginning...and if there was a beginning, how did it begin? Krauss's ideas about that are speculative, however since they have some foundation in quantum mechanics which is supported by lots of experimental evidence, they may not be as speculative as string theory which doesn't appear to be supported by any experimental evidence, yet, according to proponents of the idea like Greene.

If you know someone with a better idea about the beginning of the universe, who is it and what is the idea?

reply to post by Arbitrageur


His idea is very childish, illogical,thoughtless, not cautious, not careful, and created purely from one misinterpretation after another to reach a purely inaccurate and impossible conclusion.

After watching several of his lectures I could have easily smiled and said to my self "wow, that guy is awesome, so smart, so admirable, these are such good ideas, they make so much sense..." I couldnt do that (insert Arbitrageurs witty diss against me, about how the reason I couldnt accept his brilliant explanation was do to a fault in me and my intellect).

He is hung on the idea that literally "the universe came from nothing" (he starts with a childish conclusion, and then tries to fudge his way to the start, using sketchy, ill understood observations and experimental data and interpretation).

If that is his statement on face value "the universe came from nothing". Define nothing, nothing =nothing. + nothing = nothing x nothing=nothing / nothing =nothing + infinite nothings = nothing. Well unless he can explain this situation we have, looks like hes wrong. Wait!! He can explain this situation.

Nothing, is not really nothing (see what he did there?) nothing is really something. Ahhh YAY!!!! Science is funz.

You know how he knows for sure that nothing is really something? Because when we take our instruments and place them in vacuum to measure (which is nothing right? because we know what true nothing is, and we know what true vacuum is?) particles are detected on the instrument. So these are deemed vacuum fluctuations. It wouldnt be logical for us to admit we dont really know why these quanta of energy are being detected by the instruments in vacuum, so we must assume and then believe it as truth, that the vacuum, which equals nothing, produces bits of quantized energy, from nothing, that are detected by the apparatus and thats that, the universes free lunch.

So now from that data, the next logical step would be to assume, that all the energy of the universe at one time existed as completely nothingness (like the nothing+nothingxnothingxnothingxnothing = nothingness) and then just like inside the universe, of expanding space, and compacted fields in vacuum, and ignorance of what vacuum and space really is, and the inability to create a perfect true vacuum in a lab, and the fact that walls and instruments are made of atoms, and the fact that earth is moving in different directions constantly through space, and there is probably radiation everywhere, when we measure a vacuum, and a random quanta of energy is detected. That is how the whole universe cam into existence, instead of one of the smallest possible quantas of energy, it happens to be the totality of energy, fields and quanta, and space and time itself. Buy my new book.

Originally posted by ImaFungi
reply to post by Arbitrageur

 

Nothing, is not really nothing (see what he did there?) nothing is really something. Ahhh YAY!!!! Science is funz.

Oh my goodness lol.

I cried from laughter after I read that.

That is exactly how I feel about higgs-boson, space-time, and many other main-stream concepts. It's like a game of bull# and the only people to admit it are the one's who truly want answers - not profit.

Research in fundamental sciences such as particle physics almost never makes many people any profit. It might pay lots of engineering companies money to build stuff but the people interested in the science itself tend not to make any cash other than a pretty average salary.

There is a saying in the field that "If you want to make money, don't do particle physics"

reply to post by ImaFungi

Thanks for the detailed answer, except it doesn't really answer my question, which again is:

Originally posted by Arbitrageur
If you know someone with a better idea about the beginning of the universe, who is it and what is the idea?

I already stated his idea is speculative, and you elaborated on some ways which you think it's speculative. While I could quibble about some of your characterizations, the bottom line is we have no disagreement about the speculative nature of his idea of the origin of the universe.

One alternative is to simply shrug and say we really don't know exactly how and why the universe began...and I have no problem with that.

But if someone is going to speculate about the beginning, I can accept that 3 different people may come up with 3 different speculative ideas, none of which can be proven at this time. So do you think someone else has better speculation? Or are you saying that nobody should speculate and if we don't know for sure based on observational evidence, that's where the discussion should end, by just saying we don't know?

It seem to me that some speculation might be helpful to help frame how we might make observations to prove or disprove the speculative ideas. So if we just stop at "I don't know", while that may be true, by itself the statement isn't advancing science. Speculative ideas have the potential to advance science if they can lead to testing and experiments, or new observations.

Lastly, if you listened to the 2013 Stockholm presentation by Krauss (I posted the link earlier), he is very open about things like problems with theoretical physics, and how theoretical physicists often think they are right until new evidence proves them wrong (and in his string theory debate he points out why this is relevant to string theory and its lack of experimental evidence). I didn't get the impression he's trying to sell the speculative parts of the presentation as more than speculative.

Originally posted by Bleeeeep

Originally posted by ImaFungi
reply to post by Arbitrageur

 

Nothing, is not really nothing (see what he did there?) nothing is really something. Ahhh YAY!!!! Science is funz.

Oh my goodness lol.

I cried from laughter after I read that.

That is exactly how I feel about higgs-boson, space-time, and many other main-stream concepts. It's like a game of bull# and the only people to admit it are the one's who truly want answers - not profit.

When I hear scientists say that empty space isn't really empty, it does sound odd, but instead of laughing, I do some research and try to figure out why they say that, and end up reading about things like vacuum energy. You can learn more that way.

reply to post by Arbitrageur


The idea that the universe came from nothing is logically self refuting, so that cannot be a possibility.

The only possibility is that the energy of the universe has always existed in some form or other.

As for how the energy of the universe is supplied, I think it is either; energy is pouring into the universe (like a hose filling up a swimming pool). Or the universe as an energetic system is all that exists, and is self propelling, so like an infinite newtons cradle, or a snake that eats itself, or a snake that doesnt need to eat at all, but can infinitely propel itself forward using only its mechanics. Like falling down a never ending hill.

I know you will have a problem with that, as even I do, as they are silly. The biggest problem then is the idea of heat/radiation death of the universe. If energy/matter/galaxies is the stuff that exists in reality, and it is isolated and grouped in relatively the same area, compared to whether or not there is infinite space surrounding the energy/matter/galaxies. The problem is if all the stars burn out, and entropy continues to increase, and everything turns to radiation, does that keep traveling on for literal infinite, and does that not have no hope of ever creating anything of order or significance again? Or is that the end of reality? If so, how did this universe exist, that was the beginning of reality? Before that Nothing has ever happened, and nothing has ever existed, and this universe is just a brief burst of everything that could ever be, and it happened nowhere, for no reason, only once, and then will its energy turn to literal nothing again? Or will the radiation travel on for literal eternity?

Dark energy was created when all the energy was created in the (big bang theory) but after everything dies, is it assumed dark energys rate will not stop or slow down, it has an inexhaustible reserve of exponentially increasing energy power? Could it be that dark energy and the expansion of the universe is proportional to the entropy of non dark energy, energy/matter, and that dark energy is the yin to that yang, and so 'time' and the relation ship between energy and its entropy, is the universe turning inside out, so by the time entropy is 100% the new universe that is began at that moment is made from all the stored energy that is kinetic right now? So instead of an infinite hill, it is more like a see-saw between 2 equal people, or really, one person (the universe...energy) incrementally sliding to one side of the seesaw, and then sliding back...so a better analogy would be a skateboarder in a half pipe. Or an hourglass that while the sand is falling is being rotated, to a degree that the sand never stops passing through the middle.

reply to post by Arbitrageur


What is vacuum energy exactly? Do we at least agree in causality, all things that occur, are caused to occur by something, which was caused to occur by something, which was caused to occur my something, (something can be replaced with somethings, if multiple things caused something to occur)?

So then musnt we agree, that there is a reason, or cause, as to why 'energy' is detected in the vacuum? Or are you claiming that the axiom that energy is not created or destroyed is false, because energy is created from nothing in the vacuum all the time?

reply to post by ImaFungi

Originally posted by ImaFungi
reply to post by Arbitrageur

 

His idea is very childish

Originally posted by Arbitrageur
...if someone is going to speculate about the beginning, I can accept that 3 different people may come up with 3 different speculative ideas, none of which can be proven at this time. So do you think someone else has better speculation?

Originally posted by ImaFungi
I know you will have a problem with that, as even I do, as they are silly.

OK so that's 2 ideas, one childish and your idea that you call silly. I'm sure we can find a 3rd idea, with no more evidence than those two.

Originally posted by ImaFungi
The biggest problem then is the idea of heat/radiation death of the universe.

If by problem, you mean that nobody seems to like the idea, I concur that most people don't seem to like it.

But if by problem you mean that the universe can't possibly work this way because it offends our preferences on the way we'd like the universe to work, I have to respond by saying it appears the universe is indifferent to our preferences, and whether we like or dislike what it does and how it does it.

Einstein didn't like God playing dice with the universe when he made his famous quote "God doesn't play dice with the universe". But all experimental results so far have demonstrated the universe doesn't work according to the preference of Einstein in this specific regard, where all experiments show that in effect, "God plays dice with the universe" so to speak. So you are in good company with Einstein, if the universe doesn't work the way you'd like it to.

Originally posted by ImaFungi
So then musnt we agree, that there is a reason, or cause, as to why 'energy' is detected in the vacuum? Or are you claiming that the axiom that energy is not created or destroyed is false, because energy is created from nothing in the vacuum all the time?

That's a darn good question. I think it's generally true, but it may be false in that example, but not because energy is created in the vacuum. In a given amount of vacuum, the energy already exists, so it's not being "created".

However what we think is being created is more space (as in the Metric expansion of space), and if all the new space being created contains dark energy, then the amount of energy in the universe would be increasing. However since we don't really understand dark energy, we can't be sure about this until we understand it better.