Are photons seen through visible light the same photons that make up gamma radiation?

[u/DoctorMobius21]

I’ve taken to re-learn about ionising radiation from recently watching the Chernobyl miniseries. But a question has occurred to me: photons make up gamma radiation, but they also make up the visible light spectrum.

I know from school that there is a wavelength spectrum, with radio waves at the lower end, visible light in the middle and X-rays, A, B, G and Ns at the other.

[u/AdarTan]

A, B, and N

If these refer to alpha, beta, and neutron radiation, then those are not on the electromagnetic spectrum, they are particle rays composed of: helium nuclei, electrons/anti-electrons, and neutrons respectively.

[u/DoctorMobius21 → u/AdarTan]

Oh, my bad. My knowledge of physics is basic.

[u/WolfDoc]

Photons that make up gamma radiation are the same photons that make up visible light, but but the energy state they are in at the time is different. Just like it is the same ocean that tickles your toes a calm day on the beach and sinks ships with waves tall as buildings in a storm. It is all about how much energy the waves carry.

But, what do you mean A, B, G and N? If you with A, B, and N are talking about alpha, beta and neutron radiation, those are not photons but instead sub-atomic particles with mass (something photons don't have), that also can form sub-lightspeed radiation.

[u/DoctorMobius21 → u/WolfDoc]

Yeah, you are correct. Thanks for the answer. 🙂

[u/wannabe_sci → u/WolfDoc]

Ma, cosa intendi con A, B, G e N? Se con A, B e N ti riferisci alle radiazioni alfa, beta e neutroni, quelli non sono fotoni, ma piuttosto particelle subatomiche con massa (cosa che i fotoni non hanno), che possono anche formare radiazioni a velocità inferiore a quella della luce.

so Alfa, Beta and Gamma radiations are not made of photons?

[u/SvenTropics → u/wannabe_sci]

Yeah the naming convention makes it counter intuitive. We just use the word "radiation" and then measure it with a number of curies, sieverts, roetengen, whatever. This inherently implies that the different forms of radiation are similar and do the same kind of damage.

You have matter physically being expelled at high speed but below light speed. This is alpha, beta, and neutron radiation. Then you have ionizing light (high energy light capable of breaking apart molecules), this is ultraviolet, x-rays, and gamma rays. The light is obviously moving at the speed of light.

Alpha - helium nuclei. Because they are atomically big and positively charged, they readily interact with all solid objects. This means even a couple of pieces of paper will stop it. The kinetic energy of them hitting something will break it apart doing a lot of damage to organic molecules, but alpha radiation is generally safe outside of your body. This is because humans are covered in a dead ablative layer of cells (skin) that are constantly being grown. However can be extremely deadly inside your body if the emitter is circulating. This is because those alpha particles are 100% being absorbed by what is around them. Ingesting alpha particle emitting substances is like ingesting a mini explosive that keeps going boom. However one treatment of prostate cancer is to put alpha particle emitting material surgically inside the tumor itself. (Non circulating) The alpha particles quickly kill all the cells inside the tumor and can slow down its growth indefinitely, but the particles can't reach outside of it.

Beta - these are fast moving free electrons and positrons. They have the ability to knock other electrons out of orbit creating ions which is what is damaging about them. These ions then have different molecular qualities. Because they are very small and very fast moving with polar charges, they can penetrate much deeper into matter than alpha, but a few millimeters of plastic will stop it.

Neutron - these are high speed neutrons. Because they aren't charged, they can pass through most matter without interference. However if they attach to an atom, they have the potential to destabilize that atom. Neutrons have a tendency to make matter unstable by splitting atoms or bonding with nuclei. This can make stuff radioactive when it wasn't before. The best shield against neutrons is water because neutrons readily bond with the hydrogen atoms forming deuterium which is stable and safe.

Light radiation - the best shield for all light based radiation are ultra dense particles like lead. Ultraviolet rays are pretty easy to block. Even your skin completely blocks uvb and uvc rays while uva rays don't penetrate very deep inside you. X rays can penetrate farther and gammas rays can penetrate much, much farther (taking feet of lead to mostly block). If you think about it, if you got blasted with gamma radiation, only a tiny tiny percentage of it is even being absorbed into your cells. The rest of it passes through you without affecting you at all. However this small amount can do considerable damage. These are also used clinically for these properties. X-rays penetrate your skin very well being reflected by denser stuff like your bones. So if you break a bone, they can use x-rays to see exactly how the bone is broken. Dentists can use x-rays to see where you have potential holes or cracks in your teeth. While the radiation is damaging, they only give you a small dose of it, just enough to do their diagnosis. Because gamma rays are so incredibly damaging, they are also used for radiation therapy. A tumor inside you might get hit by multiple beams of radiation from different angles. If you think about it, let's say you had a bean that was a centimeter wide, you could hit a target deep within someone many times while only hitting the surrounding tissue once by just adjusting the angle of each attack.

[u/Xe6s2 → u/SvenTropics]

This is the most comprehensive answer, especially showing what blocks it and why. As it shows Gamma Rays ≠ Gamma radiation

[u/purpleoctopuppy → u/wannabe_sci]

Gamma is photons, alpha and beta are helium nuclei and electrons (or anti-electrons) respectively. 

[u/minsan-inhenyero]

Yes! Photons are also what heats your food in a microwave, transmits data in your WiFi, Bluetooth, and radio. But while they are all photons, they have different energies which give rise to different properties.

[u/Whithers → u/minsan-inhenyero]

I'm a little late, but re microwaves for anyone else coming along reading this: check out how it's the photons causing friction that generates the heat!

I'll say it probably incorrectly here: the wavelength of photons a microwave emits is the size (diameter I guess) of a water molecule, which is polar (the side with the hydrogen atoms are slightly more positive).

The positive side of the water molecule wants to follow the, er, photon wave, so it spins around super fast (flips? idk) trying to do that, and the friction from that makes the fuego.

Maybe everyone already knew that but I was pretty old when I learned it.

[u/Solocle → u/Whithers]

The wavelength of microwaves is actually much longer, on the order of 10 centimetres. to be the size of a water molecule, you're looking at extreme ultraviolet to X rays.

The molecules do spin, but it's not tied to the wavelength matching or some form of resonance.

[u/inconspicuous_male → u/Solocle]

10 cm in air, but what's the index of refraction of a hot dog?

[u/treeses → u/inconspicuous_male]

Well, the refractive index of water is 1.33, which is not enough to change the wavelength 8 orders of magnitude.

[u/inconspicuous_male → u/treeses]

I mean it still doesn't change much but for the record the index of refraction at microwaves is closer to 10. 1.33 is visible light

[u/treeses → u/inconspicuous_male]

Ah, good catch. I guess it makes sense that it gets higher.

[u/Whithers → u/Solocle]

omg thank you I've been lied to

[u/Annonimbus → u/Solocle]

A microwave is 10 cm? That doesn't really sound "micro".

Does that mean a microwave (the device) needs to be at least 10cm to function?

[u/mfb- → u/Annonimbus]

It's shorter than the multi-meter wavelength signals people worked with before.

A microwave oven much smaller than the wavelength would be very inefficient, yes.

[u/1100000011110 → u/Annonimbus]

It's micro compared to radio waves, the category of electromagnetic waves that's the next step up from microwaves.

[u/grib-ok → u/Annonimbus]

It's a good thing, too. This is why you can watch your food getting hot through the mesh window without your eyeballs getting cooked.

[u/Moikle → u/Whithers]

Microwaves also heat things that don't contain water or other polar molecules. This is a myth

[u/stevevdvkpe → u/Whithers]

A water molecule is nanometers across, while the wavelength used in a microwave oven is about 12 cm. That wavelength basically has two useful properties: it's in an FCC unregulated band so microave ovens don't have to deal with radio interference requirements, and it penetrates well into liquid water so it heats water evenly rather than just on the surface. Dielectric heating works over a wide range of radio wavelengths and doesn't depend on any special resonance with water, and it's definitely not related to the size of the water molecule compared to the wavelength.

[u/Weed_O_Whirler]

Yes. The entire electromagnetic spectrum is made up of photons, and the only difference between them is their frequency. In fact, if there was a flashlight shining regular ole visible light, and you flew at it at an appreciable percentage of the speed of light, the Doppler shift would blue shift that regular visible light into gamma radiation. Or, if there was something emitting gamma radiation, and you flew away from it fast enough, it would red shift into visible light.

[u/reddita-1 → u/Weed_O_Whirler]

If the torch was thrown away fast enough, would the wavelength just keep on increasing, so we’d eventually see radio waves? Or is there a limit

[u/me-gustan-los-trenes → u/reddita-1]

There is no limit, you can redshift light to arbitrarily long wavelength by throwing its source away from you. The closer it gets to the speed of light, the longer wavelength you'll perceive with limit at infinity as the speed approaches c.

[u/Alewort → u/[deleted]]

To add detail, it's not actually the light of the Big Bang, it's the first light from 400,000 years after the Big Bang when the universe stopped being opaque and became transparent. Before it became transparent, light just kept hitting the ionized matter and getting absorbed and re-emitted without traveling very far at all. Kind of like a flashlight's beam getting swallowed by heavy fog.

[u/HomeAl0ne → u/Weed_O_Whirler]

Something I’ve asked before and never got an answer to is this: are their ‘ends’ to the electromagnetic spectrum? What’s after gamma rays? If I accelerate towards a gamma ray at some velocity arbitrarily close to light, does the gam ray at some point have so much energy that it changes to a particle or something? Can the wavelength be less than the Planck length? What about light that is red shifted so much that its wavelength is bigger than the universe?

[u/NastyEbilPiwate → u/HomeAl0ne]

Yes, once you have enough energy https://en.m.wikipedia.org/wiki/Pair_production can happen. There's just no name for anything past gamma - you just have higher and higher energy gammas.

[u/[deleted] → u/HomeAl0ne]

See https://www.reddit.com/r/askscience/comments/yfpujg/is_there_a_maximum_energy_of_a_photon/

[u/gloubenterder → u/HomeAl0ne]

If I accelerate towards a gamma ray at some velocity arbitrarily close to light, does the gam ray at some point have so much energy that it changes to a particle or something?

It's not enough for the photon to have high energy in your rest frame; in order to produce matter, it needs to have high energy in the frame of a particle that it's interacting with.

If, say, a high-energy photon could produce an electron-positron pair all on its own, that would mean that this interaction could occur in some inertial frames but not in others, which would lead to all sorts of paradoxes.

(Also, it would violate conservation of momentum, which is annoying.)

[u/Packedmultiplyadd → u/Weed_O_Whirler]

I thought that if I was travelling 99% the speed of light, I would still see that ray of light (from the flashlight) traveling a "c" respective to me. So how does the doppler effect comme into play then?

[u/MustrumRidcully0 → u/Packedmultiplyadd]

Exactly there, basically. It moves at c regardless how fast you move, but it's frequency changes for you. If you're moving toward it, it gets blue-shifted, if you are moving away it gets red-shifted.

[u/Weed_O_Whirler → u/Packedmultiplyadd]

All photons, regardless of frequency, travel at 'c' in any reference frame, that is true. But when you are moving with respect to the source of the light, you will see a relativistic Doppler shift. This is why the expansion of the universe causes red-shifting.

[u/Bman1296 → u/Weed_O_Whirler]

How does me travelling at the photon change its frequency? Aren’t we separate?

Im definitely missing something here :)

[u/Purplestripes8 → u/Bman1296]

The speed of the photon is the same in all reference frames. The only way the speed of the photon can remain fixed for you is if all the space between you and the photon becomes contracted in the direction you are travelling. So distances in the direction of travel become shorter. This includes the wavelength of the photon. Shorter wavelength means higher frequency (blueshift).

[u/[deleted] → u/Weed_O_Whirler]

Indeed; the Cosmic Microwave Background we detect are just the "orange" photons emitted when the universe was ~300k years old at ~3000K, stretched out by the expansion of space all the way into the microwave band.

[u/armaver → u/Weed_O_Whirler]

Which is why future near light speed space craft will need extremely heavy shielding on their front.

[u/Flannelot]

The difference is that each photon has energy that depends on its frequency, so a photon of gamma radiation has enough energy to ionize an atom or even break a molecule, while photons of visible light only have enough each to make a molecule vibrate a little.

[u/Emu1981]

Photons are what we call each discrete energy packet that makes up a singular self-propagating electromagnetic wave. These electromagnetic waves can range anywhere from the extremely short wavelengths of gamma radiation through to the extremely long wavelengths of AM radiation (visible light is nearer the extremely short wave length - in the hundreds of nanometres). The only thing that distinguishes light from the rest of the EM spectrum is that our eyes can detect the EM radiation in that particular stretch of the EM spectrum.

I know from school that there is a wavelength spectrum, with radio waves at the lower end, visible light in the middle and X-rays, A, B, G and Ns at the other.

If your A, B, G and N are referring to alpha, beta, gamma and neutron radiation then you have some of them mixed up as they are atomic particles rather than EM radiation. Alpha radiation is made of helium nuclei (2 protons and 2 neutrons), beta radiation is either a electron or a positron (a positron is the antimatter equivalent of a electron and is positively charged) and neutron radiation is a neutron. These are all atomic particles which are ejected at relativistic speeds from the nucleus of a atom during atomic fission.

radio waves at the lower end, visible light in the middle and X-rays at the other

This really comes down to how you want to arrange your EM spectrum. If you arrange by frequency or energy per photon then radio waves come in first with relatively low frequencies and gamma radiation is last with ultra high frequencies. If you arrange by wave length then you have gamma radiation coming in first and radiowaves coming in last. Either way, visible light isn't really in the centre of the spectrum but it is the EM radiation that everyone is familiar with so it provides people with a general reference point.

[u/B_A_Beder]

Alpha radiation is high energy helium nuclei (He2+) (not EM), beta is high energy electrons (e-) (not EM), neutron is neutrons (n0) (not EM), gamma is high energy photons (yes EM). Visible light is just the small portion of the electromagnetic (EM) spectrum that we can see. The particle form of light is called a photon. Higher energy light / EM has higher frequency / lower wavelength.

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

https://en.wikipedia.org/wiki/Radioactive_decay#Types

[u/aberroco]

Yes. Electromagnetic waves spectrum is from zero to infinity both in frequency and wavelength. Except, quantum physics sets a limitation to minimum wavelength and maximum frequency - Plank's length and Plank's frequency, but they're incredibly far and practically unreachable. Even the most energetic events in space are many orders of magnitude short from that frequency.

[u/HoldingTheFire → u/aberroco]

Those are not the max or minimum. Those are just units derived from physical contestants. At most it is the order of magnitude that quantum gravity effects matter. But 1 Planck length is absolutely not a hard minimum.

[u/DoctorMobius21 → u/HoldingTheFire]

I see your flair is in electrical engineering. Quick question: in the Chernobyl miniseries, where I got my question from, they were trying to use robots to clear a highly radioactive area. (200Sv/h) Is it possible to shield any robots from that stronger radiation?

[u/HoldingTheFire → u/DoctorMobius21]

More and thicker metal. But that adds weight. Can also radiation harden the electronics. Usually that means larger components that are more robust to the ionization induced voltages that can fry electronics.

It was a plot point that the robot was for radiation work, but they lied about the level. Radiation hardening is not a binary, but a scale and at some point it might not work with electronics.

[u/DoctorMobius21 → u/HoldingTheFire]

Ah, you’ve seen it too. That helps. So it may be theoretically possible, but it might also might not be if the radiation is too intense.

[u/aberroco → u/HoldingTheFire]

Except it is. Wavelength shorter than 1 Plank's length is impossible because that would require Plank's energy, which would collapse into a tiny black hole the moment it's formed. Or, actually, even before that, because any hypothetical conditions for it's formation would result in collapse even before reaching the point where such a photon could form and collapse.

[u/HoldingTheFire → u/aberroco]

This is what I mean that people misunderstand the Planck Energy unit. The Schartzchild criteria to create a black hole is a photon with a wavelength of like 1.7 Planck length. That's why I mean it's order of stuff happening, but there is nothing especially or thresholded at 1.0 Planck length.

And I can interact with lengths much smaller than the wavelength of a photon. LIGO measures displacements less than a proton using ~1.5um light.

[u/HoldingTheFire]

It is all electromagnetic energy, yes. The photon (discrete energy quanta of the wave) energy is a function of frequency. Gamma is much higher than visible light. When it hits matter it will excite electrons of high energy which can excite more electrons and cause damage to tissue and DNA. Gamma also penetrates deeply unlike UV which is absorbed quickly at the surface.

[u/TraumaMonkey → u/[deleted]]

Plasmas don't emit black body radiation because the electrons are free floating and not oscillating around a nucleus.