šŸ‘ļø šŸŒ¹ šŸ’Ø šŸ’Ø
from BB84@mander.xyz to science_memes@mander.xyz on 24 Aug 2024 06:35
https://mander.xyz/post/17123445

cross-posted from: lemmy.ml/post/19504984

Itā€™s all relative

#science_memes

threaded - newest

lugal@lemmy.dbzer0.com on 24 Aug 2024 08:26 next collapse

Color is a social construct

JackGreenEarth@lemm.ee on 24 Aug 2024 08:34 collapse

Well, the names for different parts of the color spectrum are, I suppose. Wavelength of EM radiation, and how your brain interprets it as color, is ā€˜realā€™.

tate@lemmy.sdf.org on 24 Aug 2024 15:04 next collapse

I think they were alluding to a different use of the word color.

JackGreenEarth@lemm.ee on 24 Aug 2024 21:09 collapse

What use? The only thing I can think of is ā€˜colourfulā€™ language, which doesnā€™t seem to really make sense in this context.

tate@lemmy.sdf.org on 24 Aug 2024 22:58 collapse

ā€œPeople of color.ā€

rambling_lunatic@sh.itjust.works on 25 Aug 2024 01:47 collapse

This technically goes down a very interesting line of thought that Vsauce covered once.

Sam_Bass@lemmy.world on 24 Aug 2024 08:38 next collapse

Speed chills

[deleted] on 24 Aug 2024 12:32 next collapse

.

andrew_bidlaw@sh.itjust.works on 24 Aug 2024 12:44 collapse

<img alt="" src="https://www.youtube.com/watch?v=Ixqm8zeMD6w">

Speed kills, coming down the mountain
Speed kills, coming down the street
Speed kills with presence of mind
Speed kills, if you know what I mean

TheSlad@sh.itjust.works on 24 Aug 2024 11:42 next collapse

How fast would the rose have to be going to blueshift that much? Someone please do the math

tacosanonymous@lemm.ee on 24 Aug 2024 11:54 next collapse

Impossibly fast and it would have to be coming right at us.

vrek@programming.dev on 24 Aug 2024 12:32 next collapse

I donā€™t know about blue but here is all the math to turn a red light greenā€¦ Donā€™t think of doing it though while you could probably get out of a ticket for running a red light I donā€™t even know what the fine is for driving many thousand times the speed limit is.

Edit: just realized I forgot to post the actual linkā€¦ sciencenotes.org/fast-go-make-red-light-look-greeā€¦.

itslilith@lemmy.blahaj.zone on 24 Aug 2024 13:05 collapse

To bad the traffic light is in the speed radarā€™s reference frame, when your licence plate is on the photo I doubt the judge will care that your yellow car is clearly blue in the photo

vrek@programming.dev on 24 Aug 2024 13:49 collapse

Actually I think that would then add a additional charge for registration fraud

itslilith@lemmy.blahaj.zone on 24 Aug 2024 13:03 next collapse

For a shift from about 700nm to 350nm: coming right at you at 0.6c

It would also have a kinetic energy of about 1.1234 Petajoules, on the order of magnitude of the Tsar Bomba

BB84@mander.xyz on 24 Aug 2024 16:49 collapse

Kinetic energy or total energy? Assuming the rose weight 10 grams I get that 1.12PJ total energy, but only 0.23PJ is kinetic.

itslilith@lemmy.blahaj.zone on 24 Aug 2024 20:10 collapse

In hindsight I was a bit generous with the weight, I assumed 50g

BB84@mander.xyz on 24 Aug 2024 21:50 collapse

chonk rose šŸ˜³

Fuck_u_spez_@sh.itjust.works on 25 Aug 2024 01:27 collapse

Only 10MT instead of 50 then?

BB84@mander.xyz on 25 Aug 2024 06:57 collapse

One ton of TNT is 1E9 calories which is 4 gigajoules. So 0.2 petajoules should be only 50 kilotons of TNT?

Fuck_u_spez_@sh.itjust.works on 25 Aug 2024 07:19 collapse

A fart in the wind next to the Tsar Bomba. My disappointment is immeasurable and my day is ruined.

FleetingTit@feddit.org on 24 Aug 2024 13:08 collapse

60% of lightspeed, according to another commenter.

noodles@sh.itjust.works on 24 Aug 2024 11:45 next collapse

OK I need someone to explain this to me cause AFAIK light speed is constant no matter how fast moving the source is

bjoern_tantau@swg-empire.de on 24 Aug 2024 11:49 next collapse

Which is achieved by spacetime dilation which can in turn stretch or compress the light waves.

BB84@mander.xyz on 25 Aug 2024 07:01 collapse

While it is true that space time dilation can cause red/blueshift, that is a distinct from the doppler effect which is the primary effect here.

(dilation plays only a small role: without time dilation our answer going from 700nm to 350nm would be 0.5c instead of the 0.6c calculated below)

gnutrino@programming.dev on 24 Aug 2024 11:50 next collapse

Light speed is constant but the apparent frequency and wavelength (which roughly corresponds to what colour we see) change due to the Doppler effect

Track_Shovel@slrpnk.net on 24 Aug 2024 12:08 collapse

Fascinating

tate@lemmy.sdf.org on 24 Aug 2024 15:05 collapse

Chill, Spock.

[deleted] on 24 Aug 2024 13:00 next collapse

.

captainlezbian@lemmy.world on 24 Aug 2024 23:07 next collapse

So light is a wave. Shorter wavelengths are bluer longer wavelengths are redder. When you walk towards a wave you hit the peaks and troughs faster than had you been still. They come slower if youā€™re walking away from it. The Doppler effect is that but with light waves and velocities that make it relevant

Skalix@lemmy.world on 25 Aug 2024 15:20 collapse

Adding to the other comments; I once saw a interesting video of a visual demonstration of that effect and other weird things that happen close to the speed of light. It was this one if i remember correctly: www.youtube.com/watch?v=ge_j31Yx_yk

itslilith@lemmy.blahaj.zone on 24 Aug 2024 12:40 collapse

<img alt="" src="https://files.catbox.moe/sj2pa2.jpg">