Open Menu
AllLocalCommunitiesAbout
lotide
AllLocalCommunitiesAbout
Login

Doppler

⁨1290⁩ ⁨likes⁩

Submitted ⁨⁨3⁩ ⁨months⁩ ago⁩ by ⁨lena@gregtech.eu⁩ to ⁨science_memes@mander.xyz⁩

https://gregtech.eu/pictrs/image/4ca8ed3d-20de-43e8-9354-0e2cb0c2987b.jpeg

source

Comments

Sort:hotnewtop
  • Omgboom@lemmy.zip ⁨3⁩ ⁨months⁩ ago

    That car is speeding

    source
    • Evil_incarnate@lemm.ee ⁨3⁩ ⁨months⁩ ago

      They’d only get a light sentence anyway.

      source
      • Aurenkin@sh.itjust.works ⁨3⁩ ⁨months⁩ ago

        Depending on the frequency of the offence

        source
        • -> View More Comments
    • DogWater@lemmy.world ⁨3⁩ ⁨months⁩ ago

      I bet that guy feels like he gets where he’s going in no time at all!

      source
  • troyunrau@lemmy.ca ⁨3⁩ ⁨months⁩ ago

    Okay, just back of the envelope math. Assuming the car is truly 550nm, so the blue car is 400nm, and the red car is 700nm… How fast is the car going?

    Napkin math says 0.27c.

    Δλ=λ(V/c)

    Now someone else can figure out the kinetic energy of the car and why the whole continent just exploded…

    source
    • passiveaggressivesonar@lemmy.world ⁨3⁩ ⁨months⁩ ago

      OK now how fast did old man’s head move

      source
      • troyunrau@lemmy.ca ⁨3⁩ ⁨months⁩ ago

        Okay, napkin math… his nose is about 20cm long, and assuming it rotated about a perfect circle. The car moved say 10m. At the speed the car is moving, it covers that distance in ~120ns. So he has to move the end of his nose around a quarter circle of radius 20cm in 120ns. Let’s say 30cm total movement, for easy math. 0.25cm/ns or 0.00025m/ns. The speed of light is 0.300m/ns, so we’re talking about ~0.001c at the tip of his nose. Which is incidentally very close to the speed of sound in air.

        So, probably not quite a sonic boom off the end of his nose. Assuming my math is correct. Very strong neck muscles. Also, he’s been vapourized.

        source
        • -> View More Comments
    • Speiser0@feddit.org ⁨3⁩ ⁨months⁩ ago

      Did you take into account that the car is not driving directly towards the viewer?

      source
      • troyunrau@lemmy.ca ⁨3⁩ ⁨months⁩ ago

        I ain’t doing hyperbolic equations on my napkin ;)

        source
    • burgersc12@mander.xyz ⁨3⁩ ⁨months⁩ ago

      So about 180 million MPH. I hope he doesn’t get a ticket!

      source
    • stebo02@lemmy.dbzer0.com ⁨3⁩ ⁨months⁩ ago

      now calculate the Lorentz contraction

      source
      • troyunrau@lemmy.ca ⁨3⁩ ⁨months⁩ ago

        Instructions unclear, car stuck in dick.

        source
    • lefixxx@lemmy.world ⁨3⁩ ⁨months⁩ ago

      Why explode, the car didn’t accelerate or interact with the continent

      source
      • roscoe@lemmy.dbzer0.com ⁨3⁩ ⁨months⁩ ago

        Even ignoring the tires interacting with the road, you have air molecules.

        Here is a cool What If?" from xkcd about throwing a baseball at 0.9c.

        source
        • -> View More Comments
      • rowanthorpe@lemmy.ml ⁨3⁩ ⁨months⁩ ago

        For the same reason this baseball causes an expanding plasma-ball disintegrating everything. Fusion with air molecules that can’t get out of the way fast enough what-if.xkcd.com/1/

        source
    • Venator@lemmy.nz ⁨3⁩ ⁨months⁩ ago

      someone else can figure out the kinetic energy of the car and why the whole continent just exploded…

      It’s not on fire or melting the asphalt beneath it, so it must be really aerodynamic, and have really low rolling resistance tyres…

      source
  • gofsckyourself@lemmy.world ⁨3⁩ ⁨months⁩ ago

    Here’s the original image. It was originally posted in 2017 and has been shared so many times it was difficult to find a good copy. I had to use wayback to get this copy.

    Image

    source
  • Alabaster_Mango@lemmy.ca ⁨3⁩ ⁨months⁩ ago

    One shift Two shift Red shift Blue shift

    source
    • lena@gregtech.eu ⁨3⁩ ⁨months⁩ ago

      Blue Shift?

      source
      • danc4498@lemmy.world ⁨3⁩ ⁨months⁩ ago

        Damn, remember when Valve made half life games? It was a better time back then.

        source
        • -> View More Comments
  • ThisIsAManWhoKnowsHowToGling@lemmy.dbzer0.com ⁨3⁩ ⁨months⁩ ago

    Pretty sure the sonic boom of this car passing will kill this poor man

    source
    • marcos@lemmy.world ⁨3⁩ ⁨months⁩ ago

      Well, when that finally happens the car will be fine, far away from Earth.

      source
  • drthunder@midwest.social ⁨3⁩ ⁨months⁩ ago

    Image

    source
  • Rudee@lemmy.ml ⁨3⁩ ⁨months⁩ ago

    If that guy is keeping track of that car, his neck is def broken

    source
    • lena@gregtech.eu ⁨3⁩ ⁨months⁩ ago

      Everything around the car would be broken too, including the car

      source
  • umbrella@lemmy.ml ⁨3⁩ ⁨months⁩ ago

    thats one FAST car

    source
    • jol@discuss.tchncs.de ⁨3⁩ ⁨months⁩ ago

      And one fast head turn

      source
    • RizzRustbolt@lemmy.world ⁨3⁩ ⁨months⁩ ago

      Only as it’s moving away.

      source
  • DavidGarcia@feddit.nl ⁨3⁩ ⁨months⁩ ago

    what a beatiful green car

    source
  • Kbobabob@lemmy.world ⁨3⁩ ⁨months⁩ ago

    For some reason I can never remember which causes red or blue shift, but with this I might actually remember it

    source
    • lena@gregtech.eu ⁨3⁩ ⁨months⁩ ago

      Blue has a smaller wavelength, so when something is approaching fast it “squishes” the light, making a smaller wavelength.

      source
    • 0ops@lemm.ee ⁨3⁩ ⁨months⁩ ago

      Maybe it’s slightly convoluted but here’s how I tackle it in my head: I just think of infrared and ultraviolet, ultraviolet being greater frequencies than violet and infrared being the opposite for red. Blue is on the way from infrared to ultraviolet, so blue has a greater frequency than red.

      Image

      source
  • OhStopYellingAtMe@lemmy.world ⁨3⁩ ⁨months⁩ ago

    You can either know the position of the car or the momentum, but not both.

    source
  • Speiser0@feddit.org ⁨3⁩ ⁨months⁩ ago

    But why is the car stretched? And why doesn’t it appear rotated?

    source
    • Hazelnutcookiez@lemmy.blahaj.zone ⁨3⁩ ⁨months⁩ ago

      It’s how Doppler works.

      I don’t understand it enough to actually explain but Wiki does a pretty good job.

      source
      • nialv7@lemmy.world ⁨3⁩ ⁨months⁩ ago

        The poster you are replying to is pointing out the inaccuracies that this comic didn’t consider relativistic effects.

        source
      • Speiser0@feddit.org ⁨3⁩ ⁨months⁩ ago

        (Relativistic doppler effect)

        But does it affect the object that is emitting the wave?

        source
    • Wizard_Pope@lemmy.world ⁨3⁩ ⁨months⁩ ago

      How would you rotate it?

      source
      • Speiser0@feddit.org ⁨3⁩ ⁨months⁩ ago

        If you look at an object that is moving near the speed of light, it appears rotated, see en.wikipedia.org/wiki/Terrell_rotation.

        source
  • LovableSidekick@lemmy.world ⁨3⁩ ⁨months⁩ ago

    eeeeeeeeeeeeeeeeeeeyowwwwwwwwwwww

    source
  • DarkCloud@lemmy.world ⁨3⁩ ⁨months⁩ ago

    This is also playing on red-shift/blue-shift.

    source
    • DavidGarcia@feddit.nl ⁨3⁩ ⁨months⁩ ago

      what do you mean “also”?

      source
    • CheeseNoodle@lemmy.world ⁨3⁩ ⁨months⁩ ago

      They are the same effect just using different kinds of wave.

      source
  • BillTongg@lemmy.world ⁨3⁩ ⁨months⁩ ago

    I know just enough about the light spectrum and the red shift to understand why this is funny (thanks Prof. Brian Cox!), but it underlines how shallow my knowledge is. So much cosmology, so little time…

    source
  • Sprocketfree@sh.itjust.works ⁨3⁩ ⁨months⁩ ago

    YEA! SCIENCE JOKES!

    source
  • Gerprimus@feddit.org ⁨3⁩ ⁨months⁩ ago

    I love it!

    source
  • IDKWhatUsernametoPutHereLolol@lemmy.dbzer0.com ⁨3⁩ ⁨months⁩ ago

    Doppler’s Politics

    source