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level 1

You'd lose a perfectly good nuke with nothing to show for it.

There are a few issues that come up. The first one is that you probably wouldn't even be able to detonate it by the time it reached the sun. The operation of an atomic bomb is fairly precise, and it wouldn't really be able to function once the key parts start melting. Uranium melts at only 1405 kelvin and boils at 4404K, the surface of the sun is 5772K and the corona is even hotter. So the bomb would have long since vaporized by then. Plutonium wouldn't even need to get that hot.

There's also no fusion going on at the surface of the sun - the exact surface is a somewhat arbitrary question, but it's still fairly close to a vacuum at the relevant points, with a density under 1% of the Earth's atmosphere at sea level.

So you'd barely be hitting the Sun itself there, for that, you'd have to get down to the core. Needless to say, if your bomb wasn't holding together well at the surface, it's going to be long gone by the time it reaches the core. And of course, it's so hot there, that the center of a nuclear explosion would be a cool spot.

Finally, you've got an even bigger energy issue: by the time you've dropped a nuclear bomb from the Earth's orbit into the sun, the nuclear explosion is much less energetic than the kinetic energy of any similarly-sized infalling object. You'd first need to de-orbit the thing, which would involve a delta-v of 30 km/sec, which itself would require more power than a nuke could offer. But then as it accelerates down that long gravity well, it would be going incredibly fast, so that the collision itself would pack a much bigger punch.

level 2
Numerical Simulations | Galaxies | ISM0 points · 1 month ago · edited 1 month ago

You'd first need to de-orbit the thing, which would involve a delta-v of 30 km/sec, which itself would require more power than a nuke could offer

It looks like it's not nearly that bad - a high yield H-bomb might be 1 megaton kiloton per kg, but the kinetic energy of a 30 km/s object is about 0.1 TNT-equivalent tonnes per kg. The potential energy difference from here to the Sun is about 0.05 kilotons per kg.

level 3

There's ABSOLUTELY no way any conceived or built weapon is anywhere near 1 megaton/kg. That's a fantastically mass efficient nuclear weapon that's orders of magnitude better than everything else.

Even the W54 was ~1 ton/kg and that was meant as artillery or as a backpack carried weapon platform.

level 4
Numerical Simulations | Galaxies | ISM2 points · 1 month ago

Sorry, I think I misread and it was 1 kiloton per kilogram. They get more efficient at larger scale, so a ten tonne H-bomb can get up to about ten megatons.

level 5
History of Science and Technology | Nuclear Technology2 points · 1 month ago

The most efficient weapon the US ever made was the Mk-41, which had a yield of 25 megatons in a 4,760 kg package. So 5.2 kt/kg. For whatever that information is worth...

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