What a blow when I saw this sticker on the car in front of me:
"It this sticker is blue than you are driving too fast."
I was driving near the engineering faculty.

Now I'm curious. Why would it be blue?

I suppose It's releated to the blue shift phenomenon.

https://en.wikipedia.org/wiki/...

Hope you weren't driving then

https://en.wikipedia.org/wiki/...

If you move with high speeds, lets say at least 10-20% of the speed of light, the colors (wavelength and frequency of light) you see changes because of your motion. There are more effects present that would distort the picture, so it would be harder to read.

It's kinda the same idea when you are driving in the rain, the faster you drive, the more frequent the raindrop hits. It's not quite the same, but you get the idea. Another non-relativistic example is an ambulance driving by with sirens on: while moving towards you, you hear the sirens in a higher than actual frequency, and when driving away from you you hear it in a lower frequency.

Theres another nice relativistic example: if you drove fast enough, a red traffic light would appear green to you.

@Quirinus Yeah, I figured that'd be the case, but the probablity of driving at those speeds (fast enough to see Dopler's effect on light waves) seemed a bit too low :D

It didn't cross my mind it could be a nerd joke :D

It totally makes sense with Doppler Effekt / redshift.

@Haxk20 thanks for the bump-up!

whats the fine for driving 0.5c too fast?

Damn, I was hoping for some kind of active color change tech...

@Jedidja dying

@Jedidja Life, the universe and everything

It may be for relativistic speeds, but I wonder if something such as a metamaterial could e used to make it work in practice? Like for more terrestrial friendly speeds?

You ever see those images that change based on the angle you view them at?

Cops.

I stumbled upon this again and now I want to calculate how fast you have to go to see it blue... based on the standard blue and the shade of red.