Talk:2413: Pulsar Analogy

Explain xkcd: It's 'cause you're dumb.
Revision as of 17:41, 19 January 2021 by 172.69.63.183 (talk)
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I tried applying the right-hand-rule with the y-axis pointing to the right. :( I hurt my hand. Avitzur (talk) 23:22, 18 January 2021 (UTC)

Rotate your paper then do the right hand rule :)
Hand joint exercises. Gentle motions with the wrist bent backwards, and bent forwards; 3-5 circles in both directions and both postures, twice a day. 162.158.62.41 00:48, 19 January 2021 (UTC)

172.69.35.149 23:38, 18 January 2021 (UTC)

The analogy doesn't seem to be inaccurate in the way currently indicated. In both cases (tape measure and pulsar), conservation of angular momentum is what produces the result. With the tape measure, a small fast-spinning thing turns into a large slow-spinning thing; the opposite happens with a pulsar. 172.69.35.150 00:05, 19 January 2021 (UTC)

Isn't a tape measure bigger, not smaller, and slow-spinning, not fast-spinning, when it is elongated? This is very confusing. Thinking of how pulling the tape out stores energy. 162.158.62.41 00:49, 19 January 2021 (UTC)
A tape measure starts off not spinning. It's the acceleration of the tape as it moves in that starts the rotation, because the motion of the tape measure is not precisely radial. Same principle, different problem. Ltmauve (talk) 02:29, 19 January 2021 (UTC)
As the tape retracts, the tape inside the case is spinning. Once it is fully retracted, the case spins. Small spinny --> large spinny.
Of course, on a frictionless surface there's some slow retrograde rotation of the case + extended tape that speeds up as the tape retracts, but the case should completely stop spinning once the tape is fully retracted in that scenario, which is opposite of the analogy being drawn. 172.69.34.12 02:43, 19 January 2021 (UTC)

Currently the description starts off “Pulsars are dead stellar cores” and that phrase seems very bizarre to me, since all stellar objects are dead. Do astronomers routinely anthropomorphize to such a degree as to call some stars alive and others dead? I would think more literal language like “A pulsar is the very compact and highly magnetized remains of a star after a nova or supernova explosion” but if the acceptable astronomical parlance is to say “dead star” far be it for me to demand a change162.158.63.94 05:26, 19 January 2021 (UTC)

I find the "dead star" also odd. Sure, I know what is meant, but in the same way I know what is meant by the tape measure analogy. Neither is accurate. Side note: I removed the part about the measures' lifespan and how you could repair it as this gives no benefit for the explanation and is totally irrelevant. Elektrizikekswerk (talk) 10:18, 19 January 2021 (UTC)
The word "dead" can be used to refer to inactivity in an object that was never classically alive. i.e. dead volcanoes --188.114.102.60 15:55, 19 January 2021 (UTC)
Humans aren't the only things that can be alive or dead, so calling it anthropomorphization is way off mark. But besides that, stellar objects aren't all "dead", they're non-living. You have to be alive and then die to be dead, in the biological sense. But in this case, it's called a "dead stellar core" because it no longer has sustained fusion reactions which is what stars are known for. Since that's generally what stars are known for, that's why they're called "Dead", just like a battery that's used up all of its charge is called "Dead" - not because we're assigning human qualities, but because it doesn't do what it's supposed to. Same with any non-living thing that doesn't function as expected being referred to as dead. --172.69.63.183 17:41, 19 January 2021 (UTC)