Do Photons Cast Shadows?
598,865
Published 2019-11-06
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This video is about two-photon (gamma-gamma) physics, and how photons can interact with each other - either mediated by a passing lepton, or gravitationally via lensing, or via vacuum fluctuation pair production of vertical particles (electron-positron pair, for example). This is the so-called "box diagram" feynman diagram.
REFERENCES
Water waves interact with each other (weakly nonlinear shallow water waves)
en.wikipedia.org/wiki/Korteweg%E2%80%93deVriesequa…
mathworld.wolfram.com/Korteweg-deVriesEquation.htm…
Paper: Absorption of Very High Energy Gamma Rays in the Milky Way
arxiv.org/pdf/1608.01587.pdf
Paper: Observing light-by-light scattering at the Large Hadron Collider (LHC)
arxiv.org/pdf/1305.7142.pdf
Mass-Energy Scale
labs.minutelabs.io/Mass-Energy-Scale/
Optical Depth
en.wikipedia.org/wiki/Opticaldepth
The electromagnetic spectrum and photon energies
labman.phys.utk.edu/phys222core/modules/m6/The%20E…
Gravitational Lensing
andybohn.com/research/lensing.html
Ask an Astrophysicist on gamma ray scattering and energies in cosmology
teacherlink.ed.usu.edu/tlnasa/reference/imaginedvd…
Measuring Vacuum Polarisation with High Power Lasers
arxiv.org/pdf/1510.08456.pdf
Detecting vacuum birefringence with X-ray free electron lasers and high-power optical lasers
indico.desy.de/indico/event/12654/session/2/contri…
Vacuum birefringence in the head-on collision of XFEL and optical high-intensity laser pulses
arxiv.org/pdf/1807.03302.pdf
ATLAS makes first direct detection of Light-by-light scattering at the LHC
atlas.cern/updates/press-statement/atlas-sees-firs…
Two Photon Physics
www.hep.ucl.ac.uk/opal/gammagamma/gg-tutorial.html
en.wikipedia.org/wiki/Two-photonphysics
Thesis: The Opacity of the Universe for high and very high energy γ-rays
inspirehep.net/record/1254304/files/desy-thesis-13…
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All Comments (21)
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I guess knowing whether photons can cast shadows can help me complete my Eng Lit project due in 6 hours.
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"Well of course they d- wait... what do you mean by a... hm." ... click
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Me: about to go to sleep Also me: see title Also also me: "I dont need sleep. I need answer"
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I feel vindicated I asked this in class once and my professor looked at me like I was stupid
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YouTube algorithm: More watch time means more money Minute physics: makes a 3 minute video
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So basically: here are 3 possible ways. None of them work. Except it still happens.
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Me: "Oh! A MinutePhysics video! This won't take long..." Also me: spends 30 minutes reading the comments.
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Dont you hate it when your lamp casts a shadow and blocks out the sun!? I need to turn off the dark
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1:52 "Even very, very carefully controlled experiments with ridiculously high-powered lasers" draws red lasers with small amplitudes and large wavelengths
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You should add details in the description regarding the definition and difference of 'interact' vs 'constructive/destructive interference'.
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0:12 - Vsauce music plays
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The last minute or so about gamma waves interacting with comic microwaves literally disproves everything up until then
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Depends on how you define shadows, the interference patterns look as if they contain shadowy and brighter parts...
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Photons interacting with each other is a question I've had for so long, thank you very much
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"Bruh this scattering is legit dawg I'm tellin ya"
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Amazing video I always look forward to watching them
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1:11 Wait. So a very energetic photon can have gravitational field comparable to those of a DNA molecule?
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When two photons (oscillating electric and magnetic fields that satisfy Maxwell's equations) come together, they just superimpose, because the Maxwell equations are linear partial differential equations so any linear combination of solutions (superposition) will also be a solution. But physics is a model, so even Maxwell's equations have non linear corrections at higher energies. At an electric field of 10^18 volts/metre, (called the Schwinger limit) these corrections start appearing. The Maxwell's equations no longer remain linear and photons start scattering off each other. The mechanism of scattering is as explained, at such high oscillating electric field of the photons, they start decaying into electron positron pairs which scatter other photons.
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This was a really well made, well explained, and thought provoking video!
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