I got as far as “our hot needle might ignite the hydrogen layer and we’d be responsible for setting fire to Jupiter.”
(ETA they did correct that at least)
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This video is just silly if you excuse gross scientific illiteracy, or plain ol’ stupid if you don’t.
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As others have indicated here: the video’s repeated assertion of the needle moving “at the speed of light” means the whole thing can be thrown in the bin.
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Yep. I understand dumbing it down—as a dumb person myself I don’t consume anything that’s not—but you have to keep one foot in reality when you do that. Otherwise you’re just making shit up, presumably because you don’t know any better.
But hey, we clicked.
Anyway, here’s the content we were actually looking for. Bonus: no video. (Oh look, the widget is telling me someone already posted it too! Good job, team audience.)
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Well, I’ll make an exception for any scientific explanations from Egon Spengler. He was clearly smarter than the rest of us.
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Musk already has the needle and is working on the delivery. Part of his program evolves a self-driving Tesla. Keep your eye on the shy, it’ll happen any day now
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Go into your local municipality’s subreddit and see just how many people post questions like “What time does McDonald’s close?” and weep at the state of the world.
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Let’s say our ridiculous indestructible ceramic needle were traveling not at the speed of light but rather at a mere 0.92c (like Pellegrino’s Valkyrie); then, if my numbers are right, it would explode at Jupiter with a blast of about 67 kilotons of TNT, or ~4.5 Hiroshimas.
Good for some fireworks but hardly a threat to planetary integrity. The solar system is safe … for now.
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What if the solar system was filled with soup and a needle traveling at the speed of light collided with Jupiter?
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No object at rest can be accelerated to the speed of light, as others have pointed out. But if through some as yet unknown (magic) process a needle was found to be travelling faster than light, it could be slowed to the speed of light meeting the criteria for this conjecture. Einstein’s math doesnt explicitly rule out this possibility.
Dont hold your breath though.
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@frauenfelder “This video takes a look at this scenario since it is quite likely to happen.” How is this quite likely to happen? Kind of alarmist, Mark.
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… AIUI slowing a superluminal needle to the speed of light would also require infinite energy 
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That suggests an interesting calculation. We know the binding gravitational energy of Jupiter. How fast would such a needle have to be traveling to have sufficient energy to blast Jupiter apart?
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Einstein’s math doesn’t work with a needle moving faster than light in the first place. The relationship between momentum p and energy E for any moving object is:
E2 = (mc2)2 + p2c2
That means p and E…which together determine the direction something moves through spacetime…are a point on a hyperbola. There’s one branch in the future and one branch in the past, with the speed of light as asymptotes. You can’t go anywhere else unless m2 ≤ 0 (and then you have to).
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Assuming I didn’t bodge the calculations a 0.2g needle travelling at 1 - 7.6×10-47 the speed of light would have sufficient energy to blast Jupiter apart. Thing is though at high speeds you get relativistic beaming and the needle would probably just punch through without depositing all that much energy into the planet.
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It’s a pretty goofy video, most of which stems from ignoring this important point.
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This is true but there are caveats. The relativistic mass and the Lorentz-contracted length are not intrinsic properties of the needle but are relative to the reference frame you’re measuring them in. The relevant intrinsic properties of the needle are the rest mass and the proper length, and they don’t change as it is sped up. It’s not going to form a tiny black hole. Although if it’s going fast enough some of the cosmic microwave background will be blueshifted into gamma rays and start destroying the needle.
Yeah that’s my understanding too.
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That sounds right. At 90+% the speed of light, that needle goes through in a 10^-something-big of a second. I’m doing my seasonal eggnog workout, so I’m not up for calculating much right now.
At 0.9c, our magical indestructible Teflon-coated needle should pass through the middle of Jupiter in a little over half a second.
A real, nonmagical needle going that fast would blow up as I described above.
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Huh. That bugs me - not that I’m wrong about the black hole thing (I’m wrong a lot) - but that during all of my school and such, nobody called out that relativistic mass isn’t, well, the same as intrinsic mass. In hindsight it makes sense, and the needle goes boom anyway, but that leaves open the question of what a needle could potentially do if it was to hit at max velocity, presumably in the form of a ball of plasma traveling at a significant fraction of the speed of light. My gut says “Still not much” - because a half gram of wildly energetic plasma against Jupiter is super lopsided - but I have no way to even get a handle on it now. 
