# What does the photon feel when it hits an asteroid on its path to earth [duplicate]

This question already has an answer here:

If a photon was approaching earth, after 1 minute(from earths reference frame) an asteroid comes on the photons path. And it hits the asteroid, but from the photons reference frame time doesn't pass so there shouldn't have been an asteroid in the first place (from the photons perspective).So it shouldn't have collided. So does the photon feel(assuming it can) that it got absorbed without hitting anything?

## marked as duplicate by Aaron Stevens, Kyle Kanos, knzhou, John Rennie general-relativity StackExchange.ready(function() { if (StackExchange.options.isMobile) return; $('.dupe-hammer-message-hover:not(.hover-bound)').each(function() { var$hover = $(this).addClass('hover-bound'),$msg = $hover.siblings('.dupe-hammer-message');$hover.hover( function() { $hover.showInfoMessage('', { messageElement:$msg.clone().show(), transient: false, position: { my: 'bottom left', at: 'top center', offsetTop: -7 }, dismissable: false, relativeToBody: true }); }, function() { StackExchange.helpers.removeMessages(); } ); }); }); Feb 4 at 17:09

• Also this and links therein – Aaron Stevens Feb 4 at 15:43
• I don't think a photon feels much of anything, so I don't think this question is about physics. – Jon Custer Feb 4 at 15:50

And it hits the asteroid, but from the photons reference frame time doesn't pass so there shouldn't have been an asteroid in the first place (from the photons perspective).So it shouldn't have collided. So does the photon feel(assuming it can) that it got absorbed without hitting anything?

The problem is that you are imagining the photon as a sort of "thing" that is moving through space. It is not. Well, not really. What follows is a toy model.

What is travelling through space is not this little ball, but instead a message. That message says "I have such-and-such energy and such-and-such electrical charge (0 in this case) and...". Over long distances, and this is important, that message has a spherical wavefront. It's not the photon, it's the "message" about that photon, or its wavefunction.

Anyone that intercepts that message and decides to accept it makes that wavefunction "collapse", and what was a completely indeterminate location suddenly becomes very determinate indeed. Don't ask how that happens, we've been arguing for 100 years and still no one really knows.

So back to your example: In this case the wavefunction is expanding through space and it comes across an asteroid who says "sure, I'll accept the charges". At that point the photon appears at that location. It did not "exist" before that instant. So from it's perspective it took zero time and didn't go anywhere.

It's very important that you rid yourself of the entire concept of a trajectory when you're dealing with quantum objects.

• "I'll accept the charges" -> Energy? – Jasper Feb 4 at 16:00
• It's a joke about collect calls. – Maury Markowitz Feb 4 at 16:06