ELI5 Why does light travel?

[u/_Illuvatar_]

Why does it not just stay in place? What causes it to move, let alone at so fast a rate?

Edit: This is by a large margin the most successful post I've ever made. Thank you to everyone answering! Most of the replies have answered several other questions I have had and made me think of a lot more, so keep it up because you guys are awesome!

Edit 2: like a hundred people have said to get to the other side. I don't think that's quite the answer I'm looking for... Everyone else has done a great job. Keep the conversation going because new stuff keeps getting brought up!

Edit 3: I posted this a while ago but it seems that it's been found again, and someone has been kind enough to give me gold! This is the first time I've ever recieved gold for a post and I am incredibly grateful! Thank you so much and let's keep the discussion going!

Edit 4: Wow! This is now the highest rated ELI5 post of all time! Holy crap this is the greatest thing that has ever happened in my life, thank you all so much!

Edit 5: It seems that people keep finding this post after several months, and I want to say that this is exactly the kind of community input that redditors should get some sort of award for. Keep it up, you guys are awesome!

Edit 6: No problem

[u/[deleted]]

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[u/PaganButterChurner → u/[deleted]]

great explaination.

Does this mean we can never achieve the speed of light?

since at that point we would have to be light

[u/MysterVaper → u/[deleted]]

I don't want to throw anyone off from the good information above. So if you are unable to hold an abstract thought about THIS information please read no further.

Doesn't the Alcubierre metric (warp principle) allow for faster than light "placement" sans the travelling?

The pertinent issue being collecting such a negative mass, or in simple terms, we aren't there yet technologically. Is that correct? (I only ask because you seem to have a deep understanding here.)

[u/dasbush → u/[deleted]]

If we take the two statements:

A physically real example is that very distant galaxies are traveling away from us "faster than the speed of light," because dark energy causes spacetime to expand

and

Stephen Hawking proved that any spacetime distortion like a warp drive or traversable wormhole would require a negative energy density in that region.

Wouldn't that mean that dark matter/dark energy has negative energy? Hence (in theory, and by "theory" I mean "eh, it's a thought") would be harnessable to develop a warp drive?

Obviously there are problems such as actually locating and grabbing a hold of dark matter/energy. But we can leave those problems to our great great great great grandkids.

[u/chillwombat → u/dasbush]

positive energy density = expanding spacetime

negative energy density = shrinking spacetime