stupid physics questions

[venusian]

Moving the pan is causing turbulence or mixing-up particles for the bubbles to form around?

[hairy_pete]

The bottom of the pan is hotter than the just-so-boiling water, steam wants to form there (bubbles!). The weight of the (undisturbed) water restricts that. When you disturb that equilibrium, lots of steam will release for a brief moment.

[KlaxonCow]

Bit mad, this.

But, basically, a DARPA researcher reckons that he's accidentally created a real-life "warp bubble".

https://thedebrief.org/darpa-funded-res ... rp-bubble/

Like, it's tiny. And, therefore, useless. But it's, apparently, the real deal and is actually warping spacetime, exactly as an "Alcubierre warp drive" is meant to.

In fairness, Alcubierre worked out how a warp drive would have to work back in 1994 - and the physics of it makes sense, confirmed by other physicists - but, like, no-one had a clue how to ever actually build one, as it had mad requirements like "negative energy". But, more recently, someone else worked out that you could do it without the "negative energy" thing - which is good, as no-one knows how to make "negative energy" or if it's even possible.

And now this DARPA scientist has actually made a very, very tiny "warp bubble" for real.

So, if this is all true and good, then it seems "warp bubbles" are a real thing that we can actually now make. Granted, there's a world of difference between a microscopic lab experiment and Patrick Stewart engaging warp 9 - I'm thinking very much that "where the hell do we get that much energy from?" is likely the biggest problem to ever making this real for space travel - but a staple of sci-fi apparently just quietly became science fact.

"Make it so", indeed.

[RedOktober]

If it's DARPA I wonder what they were actually trying to do.

[KlaxonCow]

If it's DARPA I wonder what they were actually trying to do.

The article says that it was "custom Casimir cavities".

Goodness knows what exactly they're doing with that. There's no more details beyond that.

[lazerwalker]

Not my area of physics particularly, but looks like bollocks to me.

The paper can be found here: https://epjc.epj.org/articles/epjc/abs/ ... _9484.html

The journal itself does appear legit.

First red flag is that it's a theoretical physics article, but none of the authors appear to be theoretical physicists. Yes I know, reverse appeal to authority yada yada...

Second is that the abstract is odd. The repeated references to the fact they 'discovered' this when researching something else with DARPA funding is them making a sort of 'adjacent to authority' argument (look, DARPA gave us money, we must be legit!). I've not seen that sort of thing in an abstract before.

I haven't the time or the expertise to go through the full article, but the claim seems to be that they have performed some simulations of Casimir type effects, and it produces energy densities that if you squint look a bit like something that might produce a warp bubble. As I say, not an expert, but I did look at their first reference, which has the same first author, and I'm way more certain saying that the physics in that paper is a load of rubbish, smashing together random equations to draw bizarre conclusions.

[KlaxonCow]

Not my area of physics particularly, but looks like bollocks to me.

Yeah, I've read articles by other physicists since, who're coming out of the woodwork to make much the same arguments.

Basically, yeah, DARPA's funding it and it's been published in a peer-reviewed journal, so it superficially looks legit, on first look. But, digging down, there could be a touch of "hype" / "wishful thinking" / "grossly overstating what you've actually demonstrated".

The main scientist, Harold White, has done stuff with Alcubierre warp drives before, and might very much be seeing what he wants to see in his results. Perhaps less conscious "fraud" and more subconscious "too passionate to see his own personal biases and that he's over-reading what his results are actually saying".

Well, the good thing is that this is science. It has mechanisms to deal with this. Others can conduct their own experiments independently, to confirm or deny it. More "peer review" will bang out those biases. It'll eventually come out in the wash.

But, yeah, the initial "hype" might have been over-stated. This Harold White a bit too passionate about the work he's done on warp drives, that he's seeing it everywhere and then very seriously over-stating things: He's claiming that they've actually made the warp bubble for real. But it sounds like they've only simulated that it ought to do it, if you did it for real. And, like, those are very different claims indeed, but he's not differentiating that.

So, yes, upon closer inspection - if one is not blinded by the DARPA funding and publication in a legit journal - this might not quite be as "slam dunk" as this Harold White character was claiming. It's not proven by actual experiment. Something to investigate, but he's definitely claiming "victory" way, way too soon.

[gilesgoat]

Ok I am reading about this "new discovery" where after using an AI to analyze data from hundreds of thousand of particle collisions they tried to give an answer about "WHY we ALWAYS have a small ( but statistically significant ) difference between the readings and what theory predicted" and the "AI" turned out with "the best possible thing that would fit all is IF the proton would actually have 5 quarks instead of 3".

Thing that apparently was theorized since 1969 or such but never been proven ( cause it's very difficult to ) but "suspected" by various to be.

Also I read that "matter with 5 quarks or even more" CAN be made artificially but "it's generally very unstable" and decays pretty fast, however is NOT known for sure that if "in extreme conditions" ( like start of Big Bang or around black holes or neutron stars ) there may exist "exotic matter" that is more stable and lasts much longer ( with properties we don't know ).

And the question is .. WTF is a Quark and a Gluon ????? "how do they look like" ????

Last thing I saw tells me that "the most accurate representation of a Proton so far" is like "a ball full of entagled filaments all fuzzy"

[The ghost of raids past]

Ok I am reading about this "new discovery" where after using an AI to analyze data from hundreds of thousand of particle collisions they tried to give an answer about "WHY we ALWAYS have a small ( but statistically significant ) difference between the readings and what theory predicted" and the "AI" turned out with "the best possible thing that would fit all is IF the proton would actually have 5 quarks instead of 3".

Thing that apparently was theorized since 1969 or such but never been proven ( cause it's very difficult to ) but "suspected" by various to be.

Also I read that "matter with 5 quarks or even more" CAN be made artificially but "it's generally very unstable" and decays pretty fast, however is NOT known for sure that if "in extreme conditions" ( like start of Big Bang or around black holes or neutron stars ) there may exist "exotic matter" that is more stable and lasts much longer ( with properties we don't know ).

And the question is .. WTF is a Quark and a Gluon ????? "how do they look like" ????

Last thing I saw tells me that "the most accurate representation of a Proton so far" is like "a ball full of entagled filaments all fuzzy"

https://en.wikipedia.org/wiki/Quark

https://en.wikipedia.org/wiki/Gluon

[Dio]

And the question is .. WTF is a Quark and a Gluon ????? "how do they look like" ????

Last thing I saw tells me that "the most accurate representation of a Proton so far" is like "a ball full of entagled filaments all fuzzy"

Yeah, that's about it.

One way to think about gluons (and what makes them much more crazy to visualise than electrons & photons) is that they're sort of "recursive" force carriers in that gluons not only carry the force but also feel it too, which means that as soon as you have quarks around you get a crazy number of gluons spawned between the quarks and then between the gluons between the quarks and then even more gluons. 1% of the mass of a proton is the actual quarks. The rest is the energy stored in the complex morass of gluons swapping between them.

But also remember none of these objects is a little ping-pong ball - you have to think of them quantum mechanically. Electrons don't 'orbit' atoms - they spread out into clouds around them, where the 'location' of the electron is just a probability function. You can 'find' a quark in the proton by blasting it with a high energy particle beam, but just because you can locate it doesn't mean that there are three hard little lumps swimming around in there. Instead they're very much overlapping probability fields.

[Orava]

So we are made of atoms and as such overlapping probability fields?

The tenuous grip to reality surfaces.

[Orava]

Does a photon have a mass? In the 1980s it did have (a very small) mass hence our physics question of "calculate the price of one gram of light based on a 100w light bulb and current electricity prices" - several million Finnish Marks btw.

But is seems current physics thinking is of a photon not having a mass?

[Dio]

There's been no point that photons have (seriously*) been thought to have rest mass. So either you're misremembering the question (one possibility is that you were being asked to use E=mc2 to calculate the energy-mass equivalence of the photon) or Jack Black was filling in for your physics teacher that week.

* there was a brief period when it was considered as an outside crazy possibility but even the people working on those theories would have said it was pretty unlikely.

[Orava]

There's been no point that photons have (seriously*) been thought to have rest mass. So either you're misremembering the question (one possibility is that you were being asked to use E=mc2 to calculate the energy-mass equivalence of the photon) or Jack Black was filling in for your physics teacher that week.

* there was a brief period when it was considered as an outside crazy possibility but even the people working on those theories would have said it was pretty unlikely.

e=mc2 rings a bell but does it still give an energy-equivalent of mass to a photon? My physics teacher was a legend, taking pupils on a table to demonstrate gravity by spinning them around.

[zip accident]

There's been no point that photons have (seriously*) been thought to have rest mass. So either you're misremembering the question (one possibility is that you were being asked to use E=mc2 to calculate the energy-mass equivalence of the photon) or Jack Black was filling in for your physics teacher that week.

* there was a brief period when it was considered as an outside crazy possibility but even the people working on those theories would have said it was pretty unlikely.

e=mc2 rings a bell but does it still give an energy-equivalent of mass to a photon? My physics teacher was a legend, taking pupils on a table to demonstrate gravity by spinning them around.

It is a strange one. The rest mass of a photon is zero, but the speed of light is effectively infinity (in terms of the energy needed to reach that speed), so zero multiplied by infinity is definitely less that infinity, and a photon is never at rest, so a photon in motion may have a tiny mass, because it has energy. It doesn't make sense whichever way you look at it.