Does a photon observe other photons moving past it at the speed of light?
They say that the speed of light is the same for all inertial observers, but what if the observer is a particular photon within a laser beam? Each photon in a laser beam would see all the other photons passing it at speed c, therefore the laser beam would instantly break up. How do you solve this conundrum?
The answer is that a photon can't count as an observer. Time slows down for objects that move at close to the speed of light. For an object moving *at* the speed of light, time would grind to a halt. So how fast you clock something moving past you if you can't measure time turns out to be a nonsensical question.
Get More 'Curious?' with Our New PODCAST:
- Podcast? Subscribe? Tell me about the Ask an Astronomer Podcast
- Subscribe to our Podcast | Listen to our current Episode
- Cool! But I can't now. Send me a quick reminder now for later.
- Why can't relative velocities add up to more than the speed of light?
- Why doesn't light from distant galaxies reach us instantaneously?
How to ask a question:
If you have a follow-up question concerning the above subject, submit it here. If you have a question about another area of astronomy, find the topic you're interested in from the archive on our site menu, or go here for help.Table 'curious.Referrers' doesn't existTable 'curious.Referrers' doesn't exist
This page has been accessed 21273 times since September 16, 2003.
Last modified: September 16, 2003 11:28:20 PM
Ask an Astronomer is hosted by the Astronomy Department at Cornell University and is produced with PHP and MySQL.
Warning: Your browser is misbehaving! This page might look ugly. (Details)