I was reading about Peter Higgs on wiki. There are some seriously clever people out there and he's one of them. I've met one or two gifted people in my life, and their ability to join the dots almost instantly and correctly was almost frightening. I worked with one guy who had his PhD in solid-state physics at 23.
https://en.wikipedia.org/wiki/Peter_Higgs
A lay persons guide to the Higgs Boson https://www.ph.ed.ac.uk/higgs/laypersons-guide
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I found an interesting Physics channel this morning. I watched the one explaining electron spin in hope, but was really none the wiser at he end. 🙁
This one was good though. We have often puzzled how photons have no mass, yet have momentum.
You know, the full Einstein equation E^2 = m^2 x c^4 + p^2 x c^2 where m is zero...
Mahesh did a good job on this. Long story short, the photon momentum comes from the magnetic component. The electric component just makes the target electron wiggle up and down. The magnetic component then gives the moving electron a push along the axis!
First notice light pressure from the Sun moves a Comet's tail away so is imparting momentum:
And the full enchilada:
This is a Maxwell's Equations approach, of course. You can do it other ways too. Especially the full 4 Potential relativistic approach, where the electric and magnetic forces are just different aspects of one force called electromagnetism.
I shall be catching more of his stuff. Very visual, which I like. 😎
This one was good though. We have often puzzled how photons have no mass, yet have momentum.
You know, the full Einstein equation E^2 = m^2 x c^4 + p^2 x c^2 where m is zero...
Mahesh did a good job on this. Long story short, the photon momentum comes from the magnetic component. The electric component just makes the target electron wiggle up and down. The magnetic component then gives the moving electron a push along the axis!
First notice light pressure from the Sun moves a Comet's tail away so is imparting momentum:
And the full enchilada:
This is a Maxwell's Equations approach, of course. You can do it other ways too. Especially the full 4 Potential relativistic approach, where the electric and magnetic forces are just different aspects of one force called electromagnetism.
I shall be catching more of his stuff. Very visual, which I like. 😎
Mahesh looks too pleased with himself by far! 😀
Maxwell predicted that an electromagnetic wave carries momentum. An object absorbing an electromagnetic wave would experience a force in the direction of propagation of the wave.
As illustrated above for the special case of electrons whose motion is highly damped by the resistance of a sheet of metal.
Maxwell predicted that an electromagnetic wave carries momentum. An object absorbing an electromagnetic wave would experience a force in the direction of propagation of the wave.
As illustrated above for the special case of electrons whose motion is highly damped by the resistance of a sheet of metal.
If you think of a photon as a perturbation of a time field, this is pretty easy to grasp. As is the propagation of energy through a vacuum. No Ned for ‘ephemeral fermions’ or ‘quantum foam’.
"Ned" is a Scottish term applied to hooligans, louts or petty criminals. 😊
A Ned is identifiable both by his attire and by his fondness for the 'Buckie'.
The dust tail of a comet is formed by radiation pressure (photonic momentum) while the ion tail (gas tail) is formed by the solar wind.
There's a nice description here: https://astronomy.swin.edu.au/cosmos/C/cometary+tails
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We don't yet know enough about binary neutron star mergers to make any meaningful conclusions in respect of the observation described in your link.
Only two such mergers have so far been observed through their emission of gravitational waves, the first in 2017 and the second in 2019.
Only the 2017 marger was seen in both gravitational waves and in light, so it's early days to draw any conclusions regarding the observed time delay of 1.7 s between the cessation of the inspiral gravitational waves and the production of light at the point of merger.
What is impressive is that, considering the merger occurred 130 million light years away, the speed of gravitational waves has been found to be the same as the speed of light to better than 1 part in a quadrillion (10^15)!
I say this in the nicest possible way @Mister Audio, but I feel that if you post a time-consuming link, you should tell us why we should care and perhaps give a summary to the best of your ability.
Then we can discuss it.
Ethan Siegel is a respected journalistic hack in the Physics community, but I hit a big "So What?" on that one. 🙁
It is interesting to speculate whether Photons, Neutrinos or Gravitational Waves are faster.
Consider the case of the Monday February 23, 1987 07.05 UT Supernova event called SN1987A, much nearer at 168,000 light years:
https://en.wikipedia.org/wiki/SN_1987A
JWST has taken some goodish composite pictures recently, 35 years later:
What was weird is the neutrinos (which we think have a small mass) arrived 3 hours before the (massless) visible light.
There are other explanations involving scattering by interstellar dust and interstellar ions changing the refractive index of Space, but really, who knows?
https://www.aavso.org/vsots_sn1987a
For sure there is not much difference speedwise between photons, neutrinos and gravity. This is my limited conclusion. 🙂
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LIGO was interesting mostly for the challenge of developing a vibration isolation so great and effective that thry couid differentiate the difference between noise and a real gravity wave the amplitude of which is only the diameter of a lousy proton.
If there's anything that bothers me about that link, its that the article is watered down. I see the part after the colon as unnecessary:
I read it as repetitive, but maybe that's just me.
I read it as somewhat poetic. 😉
"Back when the merger took place, planet Earth was a vastly different place. Feathered birds had been around for only 20 million years; placental mammals for 10 million. The first flowering plants were just beginning to emerge, and the largest dinosaurs were still yet to come into being: something that wouldn’t occur until 30 million years in Earth’s future."
I didn't know there was some kind of rule re. posting a very recent article without having to present a summation.
Whether the article is time wasting surely rests with individual readers. You seem to have some kind of attitude going on.
Are readers aware of the quote of recent times: "Light doesn't always travel at the speed of light" ? ( I see this as truth )
* not to mention those pesky Italian neutrons called - Neutrinos *