Would we be able to predict one with reasonable precision [1] before it wipes off the face of the Earth, or would we fry with gamma rays before we knew what was going on?
1: "by this time next year we'll all be dead with 99% certainty"
Betelgeuse, the only star that I know of within the range to produce a supernova dangerous to us, has scientists looking at it closely. Mostly because it's a closeby giant and those are interesting.
I think most estimates range between 40'000 and 140'000 years until core hydrogen is exhausted. It's ejecta are unlikely to reach earth or cause harm (either radiation or otherwise). So while it lasts, you can enjoy reading a book under the light of a dying star at night for a few days.
Eta Carinae is another candidate but it's too far away and unlikely to outshine Venus significantly. It's also not due for some due. There is also the possibility it'll just collapse into a black hole with no fanfare or extra light emission, it'll just be gone one day.
Supernovae usually come from very bright stars, those are easily detectable and visible. From what I remember, there aren't any candidates even close to us that are about to expire minus Betelgeuse, which isn't aiming it's poles at us and won't do much harm.
I would like to add that in the even we could predict that a supernova is about to wipe us out, there isn't anything we could do. Any nearby object we could use as shelter, such as Venus, Mars, the Jupiter Moons etc would likely be just as affected if not more (Jupiter's magnetic field will likely make a Supernova hit more deadly IMO). It would be over within the span of a few days and nobody will survive. Just lean back and enjoy the show, tbh.
I wonder if there are any sci-fi books with a doomed planet along these lines. Pick up 10 years before the planet gets destroyed. People of the past lived with the futility of trying to escape, doing almost nothing, and now people are desperate and taking insane scientific risks to try to save the species.
If you're talking about a massive gamma burst sterilizing life on the surface of the planet there are some continuation of the planet options with a 10 year timescale. Ark submarines full of embryos that are mass produced by a world that somehow puts aside their differences and comes together for the singular goal of saving life.
Restarting the carbon cycle would require a massive effort, but with planning and lots of hard work it might be possible. The post apocalyptic world would be a strange place full of dead plants and animals that take a long time to start decaying because all of the microbiota that normally cause decay were also killed off. It would be interesting to see how fast they would spread afterward. It would give humanity a small buffer before they start releasing gigatons of CO2 into the atmosphere at least. It really depends on how well the oceans survive. If algae can come back reasonably quick the planet can be saved.
I don’t think there would be much in the way of dead plants and animals lying around. In an oxygen atmosphere any organic material would ignite, and a sufficiently intense burst would melt anything on the surface of the crust that doesn’t burn.
I loved Seveneves but I disagree that it provides an indication of how one would face this kind of emergency. For sure one would not venture into space if one fears an onslaught of harsh gamma-ray radiation. It’s an entirely different kind of disaster.
(SPOILER: Admittedly, the underground and underwater subplots might be more applicable but... they’re side-shows at best.)
There's a trilogy starting with The Last Policeman with a similar scenario: kilometer-scale asteroid projected to hit in about a year. To a first approximation everyone just says "Well, fuck, guess we're going to die." Thinking about the ways that seemed unrealistic and how I thought it would go instead, Seveneves turned out a lot more like it (though with exciting-story elements injected, and also in Seveneves they're starting from maybe a decade ahead of us in space tech). (The Last Policeman is still interesting in other ways.)
Egan's Diaspora is another good match, with an astrophysical cataclysm instead of a merely planetary one. It happens to a much more advanced future society, though.
Larry Niven has a short inconstant moon where the main character looks up at the moon which brightens to 1000 times normal brightness, what that means dawns on him shortly later.
Years ago, and it might have stolen the story from somewhere else, there was a Twilight Zone/Outer Limits/Tales from the Darkside type show and in one episode space explorers are visiting the remains of a charred planet ~2,000 light years away. They learn the star that went supernovae and that it is the star the three wise men followed to Bethlehem.
In Ring World there is a massive burst in the galaxy center and there is a race that, instead, puts its planets in formation and moves them to the edge of the galaxy.
Ultimately I'm not sure it matters if we detect a supernova that will kill us within a year. That's not enough time to do anything about it, but enough time for worldwide panic and massive suffering before we all die anyway.
We'd really need to know at least 10-20 years out. Enough time to rally the world to find a solution but not enough time that it ceases to be a concern (like thousands of years).
That's an interesting thought. Severe consequences of climate change can be expected within decades, but apparently that is still to far off and hard to imagine for many people, and hard to sell for politicians. This leaves me wondering if people would accept decades of worsening quality of life (moving into caves etc.) even if the alternative was certain death by gamma rays.
I think the climate change thing has little to do with how far off it is. It's just that the people who stand to benefit from not mitigating climate change are both powerful politically and wealthy enough that the effects, even if they happened much sooner than predicted, wouldn't likely effect them. Sure, they may lose one of their homes on the coastline. The mass migration away from coastlines will be devastating to humanity, but not to those people or their children. Heck, even worst case scenarios like massive social unrest or resource wars aren't likely to effect these people. Their kids certainly won't be going off to war!
In other words, it's not a problem of being able to imagine the effects. I suspect the powerful people resisting climate change mitigation can imagine the effects, they just know those effects won't touch them.
I presume that if the astronomers did spot an imminent supernova that threatens to extinguish life on earth, we’d collectively respond by lowering interest rates to stimulate the economy...
I think that’s the real problem. We have no first hand observations of the processes around a supernova before it blows up. It may take a very long time until we will get these observations.
Would we be able to predict one with reasonable precision [1] before it wipes off the face of the Earth, or would we fry with gamma rays before we knew what was going on?
1: "by this time next year we'll all be dead with 99% certainty"