Eli5: Are photons “dangerous”, as in are they cutting through things, based on the fact that some lasers can damage solid materials?

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Eli5: Are photons “dangerous”, as in are they cutting through things, based on the fact that some lasers can damage solid materials?

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Anonymous 0 Comments

> Are photons “dangerous”

Yes*.

> are they cutting through things

No, they heat things until they explosively boil off.

* Depends on total light intensity and photon energy. X-rays are not great for you. Being 30cm in front of a stadium floodlight is not great for you (and your clothes unless you are wearing fireproof duds). Feel free to bask in the light of your kitchen lightbulb.

Anonymous 0 Comments

Photons *can* be dangerous. But they can also be completely safe.

Just like how water *can* be dangerous but I think we all agree that being afraid of consuming any water would be utterly insane.

There’s two ways photons can be dangerous. In a pretty major simplification, it’s when each individual photon has a ton of energy or where there’s a huge number of photons.

For the first thing you have probably heard of UV light, that’s why it’s dangerous. Each individual photon can do damage. This is also the case for x-rays, and gamma rays. But *not* the case for other types of light. Like visible light, infrared, microwaves, radio waves, etc.

The 2nd thing is mostly how lasers work (at least the visible light ones), you just blast a ton of photons at something. And each time a photon hits the object the object heats up just a tiny bit but is otherwise fine. Under normal conditions this is completely harmless. But when that’s unrelenting the object starts heating up more and more and doesn’t have a chance to cool down.

Of course, you can combine both of these together, and they you have something really dangerous.

Anonymous 0 Comments

Photons are fundamental particles. They can be harmless or harmful depending on how they interact with the rest of the world.

What’s really dangerous is the amount of energy. The more energy something have, the more it can disrupt (break) things. The energy you absorb from photons is the difference between your wifi, the light you see and a deadly gamma ray from the sun.

Anonymous 0 Comments

Too much or the wrong type of anything is dangerous.

Countless photons are flying around constantly. Visible light are photons. Sunlight, X-rays, microwaves, radio waves, are all photons as well. 

Photons are dangerous when used like a laser to cut things the same way pressurized water or air can be dangerous.

Sunlight can be healthy, but too much and you’ll have problems. Same thing with water. 

Anonymous 0 Comments

Photons aren’t inherently dangerous, any more than a plank of wood is inherently dangerous. It can certainly cause damage if it carries enough energy/force. This is the difference between safe EM radiation and ionising EM radiation. Radiation that can ionise means that it can ‘knock’ electrons out of atoms, and a photon can’t be a little bit ionising. It either is or it isn’t. This is dangerous to humans because our very complicated cellular clockwork depends on the electrons being in the right place. Non ionising radiation is described as a feather landing on a clock, but ionising EM radiation as a bullet through the clock. One kind of photon is completely harmless and the other will obliterate your DNA.

This is NOT to be confused with alpha and beta radiation, both of these are also dangerous but calling them “radiation” is a bit of a misnomer since they’re not from photons but from atom ions.

Anonymous 0 Comments

Doesn’t the photon not release the energy until it hits a specific point?