**Question:** Is it true that a photon can be at everywhere at one time?

Keywords: electromagnetism, light, photon

Keywords: electromagnetism, light, photon

Short link to this page http://ias.im/67.1145

Yes, in theory, Quantum physics allows matter and light to behave like a wave (so a particle can be everywhere at once) or a particle (so it’s in one particular place). But it can’t really be both at once – once you’ve observed a particle in a specific place it can’t be everywhere else as well!

0I believe this one has something to do with someone putting a cat in a box?

0Well funny you should ask this, I’ve spent all day explaining to people how things can be in two places at once and how things can be in two states at once.

http://www.thebigbangfair.co.uk/viewitem.cfm?cit_id=384673

Some experiments show that when you measure it then previously it must have been in two places at exactly the same time.

Its pretty cool and pretty mind blowing.

0Sure. There are a few ways that quantum mechanics lets something be everywhere (or at least several places) at once. One way is the Heisenberg uncertainty principle. It basically tells us that the more you know where something is, the less you know about how fast it’s going. Similarly, the more you know it’s speed, the less you know about where it is. So if we know pretty much exactly how fast the photon is going, it will be spread out completely.

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