I am watching these images from James Webb telescope, and it talks about light that travelled 13 billion years!! And I am wondering then, what in this light is never disintegrating as most thing with time…?
In: 6
As far as we know, photons are a single unit that cannot be split. With that, the photon either reaches us, or goes in another direction, but there’s no real decay process that can happen
This has more to do with the fact that space is almost entirely empty. Like…so freakin empty.
So just about *anything* traveling throughout space will basically last forever unless it hits something, which is astronomically unlikely.
No, there’s not enough in the way to stop it from keeping going.
Light is a combination of a changing electric field and a changing magnetic field moving together, keeping each other going. The physics works out that when left on its own, those fields don’t get any weaker as they move. And since space doesn’t have much in it, there’s a lot of “them being left on their own”.
You could ask the same sort of thing about Voyager 1, the space probe that’s currently roaming the stars. “Won’t it eventually stop?” And the answer would be the same. “No, there’s not enough in the way to stop it.”
Light, like anything else, will keep going until something makes it stop. Sometimes you’ll have a nebula or the like that’s big/dense enough to [block out all light behind it](https://en.wikipedia.org/wiki/Barnard_68) but it’s not common.
The light does spread out, just like light here on Earth does, and the vast majority of the emitted photons miss us. But the objects we’re looking at are extremely bright, and the JWST is better at capturing light than anything else mankind has ever built. So even the extremely dim bit of light – the very few photons that happen to have been fired in the precise right direction to hit us from all the way across the cosmos – is enough.
Yeah, light keeps on going forever until it hits something.
However, unless it’s an absolutely perfect laser (which is impossible) the light spreads out over time, and since we live in a 3D space, it follows the inverse square law. The further you get away from something, it.gets dimmer by the same factor squared. Ie two identical stars, but one is 3x further away will look 9x dimmer.
Also, since the universe is expanding, light gets redshifted, meaning the wavelength increases, it gets harder and harder to make out objects from lower wavelengths, and then eventually we see the cosmic microwave background, which is an image of what the universe was like right after the big bang.
Latest Answers