I want to drink beer with you.

I think we're in the same part of the country. First round's on me!

 

https://arxiv.org/pdf/1807.10553.pdf
So, to sum up, to a person standing on the surface of the Earth when it turns into blueberries ...

Blueberry multiverse.

 

https://arxiv.org/pdf/1807.10553.pdf
So, to sum up, to a person standing on the surface of the Earth when it turns into blueberries ...

Blueberry multiverse.

Now that is beauty.

 

https://arxiv.org/pdf/1807.10553.pdf
So, to sum up, to a person standing on the surface of the Earth when it turns into blueberries ...

Blueberry multiverse.

Thanks for this, @nsaspook. A blueberry Earth is something that has always concerned me.

The paper has shown it is far more hazardous than one might imagine. We must take care not to let this happen -- for the children, if nothing else.

 

Now that is beauty.

The result is that blueberry earth will turn into a roaring ocean of boiling jam, with the geysers of released air and steam likely ejecting at least a few berries into orbit3 . As the planet evolves a thick atmosphere of released steam will add to the already considerable air from the berries. It is not inconceivable that the planet may heat up further due to a water vapour greenhouse effect, turning into a very odd Venusian world.

Yes, that's the beauty of science using mathematics without falseability or experimental evidence of physical reality. Make a physically absurd (or a likely non-physical) but aesthetically pleasing theory and explore it with scientifically based extrapolated physic and math rules based on the science and mathematics of our known reality.

You can keep going down the rabbit-hole until finally The Mad Hatter brings you back to reality (testable predictions, science based on observations of nature, and it must be potentially falsifiable by new observations of nature). To me the question is how are we supposed to decide what theory to work on before it’s been tested? Arguments from beauty seem a pathway to disappointment after spending billions and decades chasing phantoms. Maxwells electromagnetic field equations were testable and backed by experimental data even before gauge theory like Yang Mills existed. Molecular Vortices are an example of a rabbit-hole Maxwell fell into that eventually pointed to physical evidence of electromagnetic waves, electromagnetic potential and field theory.
https://www.physics.umd.edu/grt/taj/675e/OriginsofMaxwellandGauge.pdf

In speaking of the Energy of the field, however, I wish to be understood literally. All energy is the same as mechanical energy, whether it exists in the form of motion or in that of elasticity, or in any other form. The energy in electromagnetic phenomena is mechanical energy. The only question is, Where does it reside? On the old theories it resides in the electrified bodies, conducting circuits, and magnets, in the form of an unknown quality called potential energy, or the power of producing certain effects at a distance. On our theory it resides in the electromagnetic field, in the space surrounding the electrified and magnetic bodies, as well as in those bodies themselves, and is in two different forms, which may be described without hypothesis as magnetic polarization and electric polarization, or, according to a very probable hypothesis, as the motion and the strain of one and the same medium. (JM, page 564)

 

https://arxiv.org/pdf/1807.10553.pdf
So, to sum up, to a person standing on the surface of the Earth when it turns into blueberries ...

Blueberry multiverse.

Hi,

This is one of the most important open questions in cosmology that everyone is asking about (ha ha ha).

Actually this does touch on something i have thought about for some years now and that is the stability of the planet. We seem to take for granted that the ground will always be at least somewhat the same as it is now, but are we aware of the extreme changes that can occur. Obviously blueberries poke fun at the topic, but super volcanoes are anything but fun. As the crust heats up the natural cooling of the interior of the Earth must degrade and so the inside must also heat up, more.
We've been quite lucky so far. We can only hope it continues.

 

Yes, that's the beauty of science using mathematics without falseability or experimental evidence of physical reality. Make a physically absurd (or a likely non-physical) but aesthetically pleasing theory and explore it with scientifically based extrapolated physic and math rules based on the science and mathematics of our known reality.

Blueberry Earth is an ironic choice for your ridicule. It's basically a light-hearted, back-of-the-napkin exercise motivated by curiosity, using plain ol' 17th-century mathematics. There's nothing beautiful or aesthetically pleasing about it, unless you count human curiosity and the ability to satisfy it as beautiful (which I do).

Physics is great that way because its laws are expressed mathematically. While blueberries might seem stupid and absurd, it's just a variable -- replace "earth made of blueberries" with "atmosphere made of carbon dioxide" and the same what-if question allows us to calculate the air density of Venus, which is pretty useful for doing real science-y stuff like landing probes on other planets.

What-if questions have always been an essential part of physics, perhaps the most fundamental.

For anyone who didn't read it, the paper started as an answer to some user's question on the physics stackexchange website. As the site generally doesn't entertain what-if type questions, the thread was closed by the moderators before the paper's author could submit his answer. Rather than throw away his work, the author wrote his answer as a short paper and uploaded it to the un-moderated Arxiv archival service. It's not as if a physics journal published it, so it doesn't make a good effigy for "rabbit-hole physics".

You can keep going down the rabbit-hole until finally The Mad Hatter brings you back to reality (testable predictions, science based on observations of nature, and it must be potentially falsifiable by new observations of nature). To me the question is how are we supposed to decide what theory to work on before it’s been tested? Arguments from beauty seem a pathway to disappointment after spending billions and decades chasing phantoms. Maxwells electromagnetic field equations were testable and backed by experimental data even before gauge theory like Yang Mills existed. Molecular Vortices are an example of a rabbit-hole Maxwell fell into that eventually pointed to physical evidence of electromagnetic waves, electromagnetic potential and field theory.
https://www.physics.umd.edu/grt/taj/675e/OriginsofMaxwellandGauge.pdf

(Trying to read your post with that damned looping gif in the way gave me a headache, thanks.)

Right, that is precisely the question: how do we decide what theory to work on before (expensive) testing can be accomplished? The way it's currently done in fundamental physics is to lead with the math (which is cheap), then verify with experiments, modifying the theory as necessary. Rinse and repeat. The two most successful physical theories ever, relativity and the standard model, were built this way. It's a proven method.

If you can think of a better way, let's hear it. I get that you see theoretical physics as a rabbit hole of mathematics, but what's the alternative? Blindly design, build, and staff as many labs as possible in the hope that one of them will stumble on something interesting? There is zero chance that LIGO would have been conceived and created without the rabbit hole of GR.

Consider one of the deepest rabbit holes, the original Yang-Mills theory of the early 1950s. The theory predicted that gauge bosons have zero mass, but that would make the weak interaction infinite in extent. As the weak gauge bosons mediate beta decay -- and, hence, neutron stability -- a universe with massless weak bosons would be comprised of nothing but hydrogen. Clearly, something (mathematical) had to be changed in the theory. In the early 60s, the symmetry-breaking Higgs mechanism was proposed. It was a good idea, and in theory it worked. Twenty or so years after that, with collider technology and funding in place, the weak bosons were found at their predicted masses. Great, but what about the Higgs boson? The model allowed for a relatively wide range of possible masses/energies, all larger than the existing colliders were capable of probing. Some 50 years and several billion dollars later, the Higgs boson was found.

There are lots of different ways to design colliders, depending on the type of particles you want to collide and the energies you want to probe, all of which are influenced by the kind of physics you want to observe. Does anyone think that guessing is a good collider design principle? Why would anyone argue against having our best theoretical notions guide the design? The Yang-Mills rabbit hole led to several specifically-designed colliders being built that successfully confirmed our theories. The experimenters knew where to look and how because of the model.

Without the experimentalists, theoreticians are impotent. But without the theoreticians, experimentalists are blind.

 

I want to drink beer with you.

Count me in ... though I'd probably be just listening (and drinking) 90% of the time ...

 

Count me in ... though I'd probably be just listening (and drinking) 90% of the time ...

We'll use you as comic relief.

Oh...and you can pick up the tab.

 

We'll use you as comic relief

time and again, you've proven to be much better at that than me ... and sure, I'll pick up the tab, and hand it to you ...

 

We'll use you as comic relief.

 

Without the experimentalists, theoreticians are impotent. But without the theoreticians, experimentalists are blind.

I agree. My prime worry is that bleeding-edge theoreticians waste a lot of time trying to solve problems that don’t exist. How many null result experiments and new pretty theories for which we find no evidence must there be? Can you blame people for thinking some theoretical physicists are full of crap? When you begin talking about untestable beliefs, you’re doing religion, not science. There are plenty of ugly things that need the energy of new theoreticians to develop possible experiments on like quantum gravity. Even if some version of the Multiverse is proven as a solid scientific fact, what physics problem in our universe does it really solve? It's a “Theory of Anything,” it allows everything but explains nothing. I don't want to discourage any investigation into possible explanations but a good reality check is over due IMO.

 

I agree. My prime worry is that bleeding-edge theoreticians waste a lot of time trying to solve problems that don’t exist. How many null result experiments and new pretty theories for which we find no evidence must there be?

How many authoritarians do we need telling other people where their valuable time is best spent?

As long as government (i.e. taxpayer) money is not involved, individuals should be free to embark on their own flights of fancy. Of course, they should also be free to suffer the consequences of failure.

 

How many authoritarians do we need telling other people where their valuable time is best spent?

As long as government (i.e. taxpayer) money is not involved, individuals should be free to embark on their own flights of fancy. Of course, they should also be free to suffer the consequences of failure.

+1

Just don't try to pawn off advanced mathematical speculation as science.

 

It does make it hard when people can't follow along because of the math. It's been my biggest problem......explaining the concepts mathematically. I think they can see what I'm saying..........but they just can't understand the math.

If we could just figure out what powers the force of math. And just where and when did this math come from?

This might tell us something. Might make us smarter.

 

It does make it hard when people can't follow along because of the math. It's been my biggest problem......explaining the concepts mathematically. I think they can see what I'm saying..........but they just can't understand the math.

If we could just figure out what powers the force of math. And just where and when did this math come from?

This might tell us something. Might make us smarter.

Don't worry, it's not the math that people don't understand when you explain concepts.

 

I agree. My prime worry is that bleeding-edge theoreticians waste a lot of time trying to solve problems that don’t exist. How many null result experiments and new pretty theories for which we find no evidence must there be? Can you blame people for thinking some theoretical physicists are full of crap? When you begin talking about untestable beliefs, you’re doing religion, not science. There are plenty of ugly things that need the energy of new theoreticians to develop possible experiments on like quantum gravity. Even if some version of the Multiverse is proven as a solid scientific fact, what physics problem in our universe does it really solve? It's a “Theory of Anything,” it allows everything but explains nothing. I don't want to discourage any investigation into possible explanations but a good reality check is over due IMO.

I, too, would be worried about the health of theoretical physics if the situation really were so insular and decoupled from reality as Sabine suggests it is. Physics would be very sick indeed if every theoretical physicist was all-in on, say, string theory. But the theoretical physics community, though small, is a diverse group with diverse research interests. Its dynamics are in nonequilibrium, with theories being proposed and challenged and defended and amended, all part of a healthy Darwinian process in which, hopefully, the fittest theory survives. Reality checks are indeed good; fortunately, they're built into the community itself (watch a SUSY string theorist arguing with a loop quantum gravity guy some time!).

That the physics is framed in hyper-abstract mathematics is just a consequence of the subject matter. How else are we going to characterize gravity at the quantum scale?

 

Here's my 2¢ to the discussion:

The way I see it, the problem raises when physicists become pig-headed obstinate with the idea of applying perfect, beautiful and simple mathematics to the real world. And I can't say that I blame them. After all, math is beautiful. But it's also a human construct, in my humble point of view (although the debate about mathematical reality is still ongoing).

Math and physics overlap, but forcing physics into pure math is a mistake. Take, for instance, the view of G. H. Hardy. In his essay "A Mathematician's Apology" he compares math to painting and poetry, and he goes even further when he says that "The mathematician’s patterns, like the painter’s or the poet’s must be beautiful; the ideas like the colours or the words, must fit together in a harmonious way. Beauty is the first test: there is no permanent place in the world for ugly mathematics."

So there it is. Mathematicians are mostly motivated by their search for beauty. While physicists should be motivated by their search for truth, be it beautiful or not. And since all physicists are, to some degree or another, mathematicians (but not the other way around), it's very easy for them to fall into the beauty trap.

Here's an interesting fact: Einstein, in his older years, became close friends with Gödel, when the latter was in his younger years. Einstein started his career as a mathematician, but later became a physicist. While Gödel started out as a physicist, and later became a mathematician ... that pretty much explains their affinity ... imagine being witness to one of their numerous conversations.

 

I, too, would be worried about the health of theoretical physics if the situation really were so insular and decoupled from reality as Sabine suggests it is. Physics would be very sick indeed if every theoretical physicist was all-in on, say, string theory. But the theoretical physics community, though small, is a diverse group with diverse research interests. Its dynamics are in nonequilibrium, with theories being proposed and challenged and defended and amended, all part of a healthy Darwinian process in which, hopefully, the fittest theory survives. Reality checks are indeed good; fortunately, they're built into the community itself (watch a SUSY string theorist arguing with a loop quantum gravity guy some time!).

That the physics is framed in hyper-abstract mathematics is just a consequence of the subject matter. How else are we going to characterize gravity at the quantum scale?

She's selling a book, I understand that but she wouldn't be writing that book and have a high level of support if it was just a trivial disagreement about research interests.
I don't have a problem hyper-abstract mathematics because it's usually a means to the end of actually simplifying a complicated problem into a simpler but still complex solution. I just think we've theorized far beyond what can argued is a extrapolation of data and informed speculation from the SUSY string theorist. Just like with computer programming some abstractions eventually include so many levels of indirection in the application framework they become disconnected from the low-level details of how the hardware actually works and the limitations of current hardware.

 

The way I see it, the problem raises when physicists become pig-headed obstinate with the idea of applying perfect, beautiful and simple mathematics to the real world. And I can't say that I blame them. After all, math is beautiful. But it's also a human construct, in my humble point of view (although the debate about mathematical reality is still ongoing).

But this is the premise in question, whether physicists are actually prioritizing mathematical beauty over everything else. If you assume the premise, then sure, boo to physicists. But I highly dispute that notion! Physicists look for mathematical symmetries because (by Noether's theorem) they lead to conservation laws. Conservation laws, in turn, put constraints on the possible solutions in the solution space. In other words, conservation laws lead to physical laws, which we really want!

For example, Newton's third law of motion ("for every action there is an equal and opposite reaction") is not some axiomatic claim about the universe; rather, it's a consequence of the conservation of momentum. Mathematically, conservation of momentum is expressed as

\(\frac{dp}{dt} = 0\)

which in English says that the change in net momentum of an isolated system is identically zero. Let the system be two particles, of masses m1, m2 and velocities v1, v2. Then, assuming the masses are constant,

\(\begin{align}
\frac{dp}{dt} &= 0
\frac{d(p_1 + p_2)}{dt} &= 0
\frac{d p_1}{dt} + \frac{d p_2}{dt} &= 0
\frac{d(m_1 v_1)}{dt} + \frac{d(m_2 v_2)}{dt} &= 0
m_1 \frac{d v_1}{dt} + m_2 \frac{d v_2}{dt} &= 0
m_1 v_1 + m_2 v_2 &= 0
m_1 a_1 &= -m_2 a_2
F_1 &= -F_2
\end{align}\)

Out of the uncountably infinite number of ways that the forces between the two particles could be related, the conservation of momentum constrains the dynamics to a single relation, a physical law.

This is why physicists are drawn to symmetries; not because they're beautiful, but because they are enormously useful!

So there it is. Mathematicians are mostly motivated by their search for beauty. While physicists should be motivated by their search for truth, be it beautiful or not. And since all physicists are, to some degree or another, mathematicians (but not the other way around), it's very easy for them to fall into the beauty trap.

Not coincidentally, Hardy hated applied mathematics. And I disagree with the notion that all physicists are mathematicians (to any extent). Physicists and mathematicians tend to look at each other suspiciously; they use the same language to do two very different things. Generally speaking, physicists don't give a rat's ass about proofs or mathematical rigor, whilst that's the entire point for a mathematician.

Physicists, even the hyper-abstract theoretical ones, are more like engineers when it comes to math: they see it as something that helps them get the job done. The important bits aren't the math!

Here's an interesting fact: Einstein, in his older years, became close friends with Gödel, when the latter was in his younger years. Einstein started his career as a mathematician, but later became a physicist. While Gödel started out as a physicist, and later became a mathematician ... that pretty much explains their affinity ... imagine being witness to one of their numerous conversations.

I don't think you have this quite right. Einstein was never a mathematician; in fact, he needed significant mathematical help (including cracking the books to learn differential geometry) to work out general relativity. Not that he couldn't have been a mathematician if he wanted, just that math wasn't nearly as interesting to him as physics.

Godel was a logician, through and through, though it's fair to call him a mathematician. But I've never seen him referred to as a physicist. Where'd you read that?