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submitted 21 hours ago by The_Picard_Maneuver@lemmy.world to c/science_memes@mander.xyz

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[-] wolframhydroxide@sh.itjust.works 9 points 17 hours ago

So, what I'm taking away from this is that, if I ever see a blue rose, it's already too late, and the object moving at relativistic speeds toward me has already probably ignited a thermonuclear reaction in the air around it, but the light from the fusion bomb before me has not yet reached me?

[-] JohnAnthony@lemmy.dbzer0.com 1 points 8 hours ago

It's fine! My math says the rose is actually moving away from you, at around a third of the speed of light.

At this speed, it orbits the earth (at sea level) 2.5 times in a second. Maybe it shoots for the moon, which it reaches in less than 4 seconds. Or it might be on its way to Neptune, which will take it 12 hours!

Also, if this red rose was actually moving towards you at the same speed, I guess it would look black, since you would receive a wavelength you can't see? Ignoring the pesky thermonuclear reaction stuff...

[-] Hadriscus@jlai.lu 3 points 17 hours ago

It's not necessarily too late ! it could be far, far from you. Far enough.

[-] wolframhydroxide@sh.itjust.works 2 points 17 hours ago* (last edited 17 hours ago)

In that case, given that a rose would need to have a certain minimum angular size to be recognisably a rose, and it would have to be outside the atmosphere to not be a guarantee of the imminent cessation of my existence, that would have to be a VERY big rose, which doesn't bode well for life on earth if it's approaching at relativistic speeds. Or are you suggesting that it's a galactic - scale rose, and we've got a few million years before it obliterates the Milky Way?