this post was submitted on 24 Feb 2024
1355 points (99.5% liked)

xkcd

8632 readers
1 users here now

A community for a webcomic of romance, sarcasm, math, and language.

founded 2 years ago
MODERATORS
 

https://xkcd.com/2898

Alt text:

"Some people say light is waves, and some say it's particles, so I bet light is some in-between thing that's both wave and particle depending on how you look at it. Am I right?" "YES, BUT YOU SHOULDN'T BE!"

you are viewing a single comment's thread
view the rest of the comments
[–] [email protected] 11 points 10 months ago (1 children)

Pretty sure you can chose earth as fix point and have everything rotate around it on really strange orbits. Everything is kind of relative.

[–] [email protected] 4 points 10 months ago (3 children)

Wouldn't that break relativity tho if you treat the earth as a fixed point? Stuff really far out would have to be going absurdly faster than light to orbit the earth once every 24h. I feel like that's one of the ways to tell whether or not you're rotating, or stuff is orbiting you.

[–] [email protected] 8 points 10 months ago* (last edited 10 months ago)

Relativity works when earth is the center because it's relative, we just calculate everything with earth as the frame of reference. It does make a lot of math harder, but that's what we already are doing when using earth based telescopes (although we try to shift the math to a more reasonable frame of reference for most stuff, but earth is always the starting point because we're making all the measurements from here)

[–] [email protected] 5 points 10 months ago

If the earth is fixed (not just in position, but in rotation), you're using a non-inertial reference frame, and things get wonky. But you can make the math work.

[–] [email protected] 2 points 10 months ago

Why would objects far out need to orbit earth every 24h?

Wouldn’t that break relativity tho if you treat the earth as a fixed point?

To be honest, physics was never my strong point. If I remember correctly you could chose any point as your observational (?) point but maybe someone with some real physics cred can chime in.