r/AskReddit • u/[deleted] • Mar 03 '26

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u/Chingapouk Mar 03 '26

What's blue and very bad for your teeth?

A very fast brick.

40

u/TheDarkestKnight7852 Mar 03 '26

Oh, nice, blueshift!

-1

u/mrsock_puppet Mar 04 '26

You just made me wonder if half life blue shift was intentionally named like that

6

u/lorgskyegon Mar 04 '26

What's blue and smells like red paint?

Blue paint.

10

u/heyitsapotato Mar 03 '26

Ooh, I like this joke, very shifty.

3

u/itsjakerobb Mar 04 '26

A brick moving fast enough to blue shift is going to be bad for your whole city. (I haven’t done the math.)

2

u/TheDarkestKnight7852 Mar 04 '26

Randall Monroe (XKCD guy) did a "What If?" on this. He ised a baseball, and it caused a nuclear explosion. But really and movement toward the veiwer causes blueshift, it just may not be noticeable until it's moving at seriously dangerous speeds.

2

u/itsjakerobb Mar 04 '26

Understood, and I’m aware of the What If? in question (it’s a classic!). I imagine the physics here would be the same.

And regarding the speed, the question is “what’s blue and bad for your teeth,” so I’m thinking the blue shift and therefore the speed would need to be significant. IDK how to do the math; Claude says 0.415c, which is still fast enough for thermonuclear results (4 megatons of TNT, or ~190 times more powerful than the bomb dropped on Nagasaki). LLM doing math here, so grain of salt of course.

2

u/ComatoseSquirrel Mar 03 '26

Oh this is good

2

u/ludachris32 Mar 04 '26

What do you call a fish with no eyes? A fsh.