[ninininino]

I don't quite understand the meaning of your comment, it reads to me like "one time people worried about something but their worries were unfounded" with the subtext/implication that "therefore we don't need to worry" - about this? Or maybe need to worry in general? Or is it just to feel a bit more optimism that not every doomsday fear ends up coming to fruition?

[gwbas1c]

> Or is it just to feel a bit more optimism that not every doomsday fear ends up coming to fruition?

Exactly.

I suspect mirror-image molecule life hasn't evolved because it wouldn't be fit enough to be self-sustaining.

[ceejayoz]

Many invasive species get into new ecosystems only with human help. They can’t do it on their own, but once they’re there… Asian carp and zebra mussels.

[mlyle]

I'm not in favor of a full-on precautionary principle for everything.

But if you take on too many 1 in 1000 or 1 in 10000 risks, eventually things go badly.

Russian roulette or reckless driving looks safe-- for awhile.

Note the person who really advanced the view of "igniting the atmosphere" with fission was Teller back in 1942, who was about the most pro-nuclear scientist you can find. They didn't just shrug and push the button: Bethe and others did a lot of math to conclude that it was exceptionally unlikely.

(Was it too much of a risk, given that we didn't have much experimental data about nitrogen-nitrogen cross-sections? Probably not, but we can't conclude that it was a reasonable risk purely on the basis of "we didn't die.")