Hacker News Reader

Comment by devoutsalsa | Hacker News Reader

Not from the video… What blew my mind was to learn that a black hole get bigger when it absorbs light. Light from a campfire you had as a kid could be feeding a black hole right now.

View on HN

> Light from a campfire you had as a kid could be feeding a black hole right now.

I don't think we have a close enough black hole for this to be true for anyone reading this right now.

Maybe, there's a theory that the 9th planet is a black hole, and that's why it's very hard to detect outside of the gravitational effects. Amusingly there's a diagram in the paper that's a 1:1 diagram (life size) in the paper.

Would be crazy if true, we could verify all kinds of things by tinkering with a live black hole.

Well, yeah, it is weird at first. But once you think about it, it is not unintuitive: if the light was just gone, that would be wrong, too, right? Also, energy == mass, so of course, it is equivalent to throw mass into a black hole or energy. The longer I think about it, the more it is mass that is the weird thing. What is mass? Something like frozen energy...

The Earth gets bigger as well, and by the same mass per photon, when it absorbs light.

It loses this mass through radiation, but then, so does a black hole. That's fancy Proper Noun Hawking Radiation, but radiation it remains.

Not trying to be a downer, I find the fact that a photon doesn't /have/ mass but still /is/ mass endlessly fascinating.

Reply on news.ycombinator.com