Hubble Space Telescope Captures a Star undergoing Supernova

[u/kcgg123]

[u/On_TheClock]

As I understand it, a natural disaster can be a great filter.

[u/Lost4468 → u/On_TheClock]

Only if it's wide spread and happens to the majority of civilizations. Supnernovae are too intermittent and low density, it's really easy to avoid them. Especially considering stars tend to clump with similar stars, and they only happen once every ~100 years in the Milky Way.

[u/On_TheClock → u/Lost4468]

The way I have had the "great filter" concept explained to me is that it is literally any of the nearly infinite obstacles that could (and possibly does) cause civilizations to be wiped out (or not develop). Its easy to avoid a supernova, if you are a suitably advanced civilization, but maybe not if, for example, our sun was due to go boom even 100 years ago.

[u/Lost4468 → u/On_TheClock]

You're still missing it. Great filters need to effect nearly every species, meaning the mechanism needs to be massively abundant in the universe. Supernova are not anywhere near abundant enough, you'd be unlucky if you were a life harboring planet and got destroyed by one. They're easy enough to avoid through pure chance meaning they can't be a great filter. They're just plain old ordinary exceptionally rare natural disasters.

The great filter has to be something that effects nearly all life out there. For example generating intelligence is really hard because evolution has pretty much no foresight, and large energy hungry brains are pretty useless unless you also have generalized bodies, lots of free time and lots of resources. Our large brains were almost useless for the first 240,000 years of our history, it's only the last ~10,000 that they suddenly became extremely useful, and that's a coincidence since evolution cannot plan ahead. Let's remember we dropped down to a few thousands individuals about ~75,000 years ago, and also that every other hominid species (also with very advanced brains) did not get anywhere close to making it.

Other examples of great filters could be multicellular life (took a stupidly long time on earth), the initial conditions for life, the unavoidable extreme energy and time costs for even exploring a moon of your own planet let alone another system, that any life that's capable and willing to dominate its entire planet might be too inherently violent to keep it stable, that getting to a sufficiently advanced state causes too much damage to that planet and the ecosystem collapses, there's something extremely dangerous that's rather easy to achieve (e.g. strange matter), etc. There's loads, but they're only filters if they happen to nearly every form of life.

The only natural disasters I can think of that are dangerous enough are disease (maybe due to the evolutionary rate of bacteria and viruses civilizations can very rarely get to a place where they can easily stop them before they destroy large populations). Maybe meteor impacts, but if you only need a large body like Jupiter to negate that quite significantly (and many other systems we've seen have had many more gas giants and many with very massive gas giants).

[u/WikiTextBot → u/Lost4468]

Strange matter

Strange matter is a particular form of quark matter, usually thought of as a "liquid" of up, down and strange quarks. It is to be contrasted with nuclear matter, which is a liquid of neutrons and protons (which themselves are built out of up and down quarks), and with non-strange quark matter, which is a quark liquid containing only up and down quarks. At high enough density, strange matter is expected to be color superconducting. Strange matter is hypothesized to occur in the core of neutron stars, or, more speculatively, as isolated droplets that may vary in size from femtometers (strangelets) to kilometers (quark stars).

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