The Doppler Bus Ride Of Cosmic Proportions

Behold the visual representation of redshift vs. blueshift in action! Left guy's experiencing the cosmic downer of light waves stretching away (redshift), while right guy's vibing with approaching light waves (blueshift). It's basically the Doppler effect's greatest hits album, but for electromagnetic radiation. Physics nerds know this as the reason galaxies appear to be fleeing the scene of the cosmic crime—the universe's way of saying "it's not you, it's me" as everything drifts apart. Meanwhile, astronomers use this phenomenon to calculate how fast celestial objects are moving relative to Earth, all while these "Gabriel's horns" (a mathematical pun on the infinitely long trumpet shape) point to our universe's expansion. The ultimate cosmic mood swing, captured in one bus ride!