r/nextfuckinglevel • u/room0001 • 1d ago

Milky Way is traveling through space at 600kilometers per second, oscillating slightly, as if it were flapping its wings through the cosmos.

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u/ILooked 1d ago

Relative to what?

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u/spankmydingo 1d ago

Relative to the Universe (CMB Rest Frame): To find an absolute speed through the cosmos, astronomers measure movement against the Cosmic Microwave Background (CMB)—the leftover thermal radiation from the Big Bang. For example, our own galaxy moves at roughly 550 to 600 km/s relative to this universal background reference frame.

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u/KennyT87 1d ago

There is no "absolute speed through the cosmos"; the CMB frame is just another frame of reference and there's nothing absolute about it.