[spetznaz]

I was watching some documentary on various types of extinction level events that can destroy life on Earth (e.g. say a major asteroid strike etc). One of the more interesting ones was a gamma-ray burst from some collapsing star within our galaxy. As it collapses, two bursts come out of opposite ends, and any thing in its path that is an organic lifeform is done (apparently even the most radiation resistant organism on Earth, some bacteria, would not be able to escape the effects). According to the program, one of the largest mass extinctions on Earth (there have been 5 of them ...some interesting reading there) called the Ordovician Extinction that killed the second largest number of lifeforms of the 5 mass extinctions was probably caused by a gamma-ray burst.

The good news? Most people exposed to it would go quickly. It is only those not directly affected who would die slowly.

Which is why I always say that one shouldn't worry too much, because if something bad ever happens it will probably be like the end of the Sopranos ...the screen will simply go black.

[SunkenCiv]

I’d like to read more about that hypothesis.

The Ordovician extinction was due to massive and worldwide glaciation that came on kinda sudden-like. I don’t find gradualist models for ice ages compelling.

There’s an iridium abundance in the terminal Ordovician stratum, but this is regarded as inconclusive (it sez here). Iridium abundance (as well as chromium) is attested at the K-T boundary, pretty much everywhere it’s been studied since Walter and Luis Alvarez articulated their theory. Iridium is also associated with the Eltanin impact which happened circa 2 million years ago.

A supernova more or less in proximity would generate (among other things) Plutonium 244 (it sez here), which is sufficiently long-lived (half-life is 80 million years) to be possibly diagnostic of a supernova explosion.