Photons affect physical attributes of a person?

Question

In theory, could photons affect, lets say, your hand, if you were to hold a flashlight pointed at it long enough? Photons are the very smallest particles (without any mass or electrical charge) that make up light. If photons can change quanta (quantum particles) speed, acceleration, direction, etc, can they have an influence over whole atoms? Or even electrons of an atom that make up something like humans.

Basically, what I want to know is your thoughts on this. If light has photons traveling at unimaginable speeds, if one was to strike an atom, could it change that atom? And, if given enough time and enough light, could that change be noticeable under certain circumstances?

I realize comparing quantas to atoms is like comparing the earth to a galaxy, but my questions are endless the more i study quantum physics. Next question will be about quantum suicide (an endless debate).

Answer 1

Of course photons change atoms, and you don't have to wait. It's constantly noticeable. How else did you think we *see* them?

Answer 2

High energy photons will cause sunburn in your skin.

Enough photons of any energy will cause your skin to heat up, and even more of them will cause it to cook.  That is what happens under a grill.  If you have enough your skin will vaporise immediately, as happens if a nuclear device explodes within a mile or so of you.

Don't be put off by complicated scientific jargon: keep in mind what is happening even if it is quantum theory.

Answer 3

Photons, being that much smaller than atoms, generally cannot directly affect atoms, at least not at the level you suggest.

The forces binding our atoms together are very much stronger than the average photon.  of course, given enough photons (like a laser, maybe?) we could change the structure of matter.

And let's not forget those special instances where certain elemets or compounds are photo-sensitive, like solar cells or photographic paper, laser printer drums, and even over the long term skin cells.

But also remember that the very basis of an element is the nucleus.  Those subatomic bonds are very much stronger than most photons, so changing one element into another with photons alone (ie, the photon weakens or destroys the nuclear bonds) is not common.