Comment by dataflow

Comment by dataflow 20 hours ago

4 replies

> If you're standing on a planet, you're accelerating under gravity, and therefore don't you see Unruh radiation?

Layman here, but if you're standing, you're not actually accelerating, right? You'd only be accelerating if there was nothing under you holding you up, meaning if you were falling down.

qnleigh 19 hours ago

Ah yeah there are multiple definitions of 'acceleration' here. Unruh radiation occurs when you're not 'in an inertial reference frame,' loosely meaning that you feel acceleration. So in a rocket in space or (presumably) standing on Earth's surface.

What you say makes intuitive sense, but it was actually the opposite logic that lead Einstein to his general theory of relativity. Here's a slightly dorky but very good Veritasium video that explains this issue and general relativity https://youtu.be/XRr1kaXKBsU?si=1iudoAx5kWgWHHt-

  • dataflow 19 hours ago

    Ah gotcha! Yeah I'm familiar with Einstein's happiest thought - it just escaped me what was meant by acceleration here for the Unruh effect. Cool!

nazgul17 19 hours ago

Also a layman. But as long as your temperature is not absolute zero, particles inside you are moving, and if they have mass, they would indeed radiate gravitationally - until they slow down to a stop, that being absolute zero.

My understanding from pop science videos is that they can indeed evaporate, but only through decay mediated by the weak force.

varjag 12 hours ago

No, you are in fact accelerating when you are standing on the planet.