# What would happen if a needle traveling at the speed of light collided with Jupiter

Originally published at: What would happen if a needle traveling at the speed of light collided with Jupiter | Boing Boing

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does this first assume a spherical needle?

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I’m glad we’ve cleared this up. I was worried.

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I assume the first thing to happen would be the dispersal of the haystack housing the needle.

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I didn’t watch the full video but it kept saying “at the speed of light” rather than something like “at 99.999% c,” which is actually a pretty important distinction because theoretically no particles that have a mass could ever quite reach that speed, so it’s a hypothetical that we don’t have a real physical model to answer. Unless I missed something?

Surely something traveling very close to the speed of light would cause tremendous damage to any planet, though.

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The needle would have infinite mass and require infinite energy to move as matter at the speed of light.

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https://what-if.xkcd.com/1/

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More like very thin disc, according to Messrs. Lorentz and FitzGerald.

There was a young fencer named Fisk,
Whose speed was incredibly brisk.
So fast was his action,
That Lorentz contraction,
Foreshortend his foil to a disc.

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It assumes an ordinary needle, made of ordinary unobtanium, traveling at the speed ordinarily associated with light.

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You didn’t miss anything. What is more, the differences in energy between 99% and 99.99% and 99.9999% get way bigger than the difference in energy from say 50% to 99%, which makes the rounding kind of meaningless.

Did Jupiter just get hit with something whose mass-energy is bigger than its own, or bigger than a galaxy, or bigger than that of the whole known universe? Because at some point the impact is the least of its worries.

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Maybe s/foil/blade/ there? Foil has two syllables so it doesn’t scan.

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So - nothing with a rest mass can go the speed of light. I’m assuming here we speed up the needle to some point arbitrarily close to the speed of light. You do that - the mass of the needle increases (and it shortens in the direction of travel, and time dialates). Make it massive enough - tiny black hole. Super tiny black holes evaporate almost instantaneously - although maybe time dilation can mess that up? So my gut says if you could accelerate a needle up to the speed of light - it will self destruct in a shower of hard radiation and cease to be. Jupiter should be fine? I could swear I read an article about what would happen if a small black hole punched thru the earth at high speed, and the answer was “very localized damage” simply because it wouldn’t interact with most of the matter due to a very small event horizon - it’d just pass thru. Can’t find the article though…

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It does? I suppose you could stretch it out to foy-ill, but most people would have no trouble saying that line so it scanned. Substitute “sword” if you wish.

(Google that limerick and see how badly many versions trash the scansion. Some try to fit “Lorentz–FitzGerald” into a line.)

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Einstein’s annus mirabilis papers were published OVER A HUNDRED YEARS OLD. There’s no excuse for someone claiming to be any sort of technical, or any kind of science popularizer, not to know that a massed particle can’t be accelerated to the speed of light in the first place.

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Former fencer here, nobody said it with a dipthong

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Well boy-ill me in oy-ill! Foy-illed again.

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Can’t tell if this channel is trying to be earnest about answering real scientific questions, or simply trying to mimic xkcd’s style.

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The Jovians would smoke it.

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