Massive thermonuclear explosions occur naturally on a daily basis on the surface of the Sun. Could the star (and by extension we humans who depend on it) survive without them? Are they necessary to the Sun?
I ask because I’ve seen so much stuff labeling nuclear detonations as unnatural and that humans by building the bomb have released terrible forces into the world that should never have been tampered with. Some, like Lynch in the new Twin Peaks, even play with the notion that the first atomic explosion, or rather first one created by humans, in 1945 broke some sort of barrier and let all sorts of evil shit into the world. Why that barrier hadn’t been breached a gazillion times over already I’m at loss to say. There’s nothing special about a nuclear explosion initiated by humans (other than its tiny size), in both cases it’s Nature at one end of the process and Nature at the other end. Sure, atom bombs can kill a lot of people, but so can ordinary bombs, and shells and bullets and gas and poison, etc, yet we don’t regard those with horrified fascination.
I guess what I’m also saying in addition to asking the initial question is whether the thermonuclear explosion has been unjustly maligned.
Strictly speaking, the nuclear explosion is what makes a star a star … otherwise the Sun would just be a glob of hydrogen … certainly any life that evolved depending on the nuclear radiation from the Sun would quickly die without it …
Thermonuclear explosions in the Sun = Good
Thermonuclear explosions in London, England = Bad
Could we survive without them? Unlikely. There are small, isolated ecosystems in the deep ocean that do not depend directly on sunlight; the geothermal activity that sustains them would continue to do so (including maintaining pockets of liquid water even as the rest of the oceans freeze solid) even if the sun were somehow snuffed out. We would not fare as well: the earth as a whole would get damn cold in fairly short order. Even if we could stay warm, we’d soon go rather hungry. I would guess that at some point the atmosphere would condense to liquid, and then freeze solid.
Could the sun survive without them? Are they necessary to the sun? Odd questions. The ongoing fusion reaction is a natural and inevitable consequence of putting so many hydrogen atoms within gravitational reach of each other. The only way to end the reaction is to take away the hydrogen, eliminating the sun itself.
It’s true that we were doing a fine job of killing people and breaking things before nukes came along; witness Dresden and Tokyo. Nukes are of interest because one bomb can do so much damage. The firebombing of Tokyo required about 300 aircraft dropping 1.6 kilotons of ordnance; Hiroshima, OTOH, was leveled by a single aircraft. The historic concern over nuclear proliferation was that someday a raging asshole somewhere might acquire the ability to kill an entire city by delivering one bomb. It turns out that Kim Jong Un is just about to become that raging asshole, and Seoul (or possibly Tokyo) may be the city that gets killed. With conventional weapons it takes a lot of time and effort to wipe out a city, and the damage can be limited by a defensive effort: the greater your defense, the less damage the guy does. But with nukes, it’s much more either-or: either the bomb never gets delivered, or it does and the target gets completely erased from the map.
Not only do the nuclear reactions occur deep in the core of the Sun, not on its surface, but it’s really a stretch to call them “explosions”. On a per-mass or per-volume basis, the Sun generates heat at about the same rate as a compost pile.
Now, how hot a compost pile will get depends on how quickly it can dump heat to its surroundings, and so larger compost piles get hotter. And a compost pile the size of the Sun turns out to need to be several thousand degrees to dump all that heat, and so that’s the temperature it gets to. But compared to its size, the reactions are still proceeding quite slowly.
And of course, that’s a good thing. The reactions are proceeding so slowly that the Sun’s fuel will last for billions of years. Explosions, by contrast, by definition use up all of their fuel in a very short time.
IIRC the earth is also warmed by nuclear reactions. The energy released by spontaneous nuclear decay is one of the main sources of core heat (and feeding those underwater hot vents). Its the classic scenario of the spontaneously burning haystack; allow a heat-generating process in a large enough volume, and don’t allow that heat to escape easily, and pretty soon the temperature gets very high.
There’s nothing particularly horrible about nuclear processes, except unfamiliarity. We understand fire, and projectiles, and we can see what hey do. Gas, horrible but generally visible. (The worst gasses are invisible).
Nuclear, besides getting so much more bang for the buck or ton, is also horrific in that it can create damage invisibly, it can have effects days, months, and years later. It’s not something we see and relate to in our daily lives.
The sun burns its fuel so slowly because it produces energy via the proton-proton chain reaction. This is a multistep process. First, two protons fuse into a diproton (which can also be viewed as a helium nucleus with no neutrons). Then, before the diproton falls apart, one of the protons undergoes beta decay and becomes a neutron, resulting in a deuterium nucleus (a proton and a neutron). This step is very rare and is mostly why the process is so inefficient. The diproton is unstable and doesn’t last long, and beta decay is rare, so for the beta decay to happen during the brief time the diproton exists is a very rare event.
Of course, this slow step is not involved in the process by which hydrogen bombs produce their energy. Hydrogen bombs start with deuterium (or tritium) as fuel.
It’s only tangentially related, but you don’t have to go as far as the Sun to find natural self sustaining nuclear chain reactions. They have happened here on Earth.
When I read this in Wikipedia years ago, I was once again floored by how *astronomical *astronomical processes are. The sun’s core generates less heat per cc than human tissue? But there’s soooo much of it that it creates that inferno in the sky! Amazing!
This also clued me in a bit about why it’s so hard to do commercially viable fusion. We don’t want our city’s power generator to only create less heat per cc of reactant than a human body; it would have to be a truly massive power plant! (We also don’t want it to be quite as active as a thermonuclear bomb.) So the sun’s fusion mechanism isn’t good enough for commercially viable power generation.
Only a very small fraction of sun’s volume is actually involved in the thermonuclear reaction. The small amount of generated heat that was quoted was not “per cc of reactant”. It was “per cc of the whole sun’s volume”.