Context: I did my diploma thesis work at that lab, and shared the office with those guys. This is a result almost 10 years in the making.
EDIT: The AMS was built and used in a lot of experiments before that. Among other things done with that instrument was measuring the neutron flux of the nuclear blast at various locations in Hiroshima, by determining the isotopic composition of the copper on building facade elements. Neutron capture produces some radioactive as well as "unnatural" stable isotopes and by determining their ratio, one can determine the neutron flux and energies.
It saddens me, that the accelerator they (and I for that matter) used for their research, has been decommissioned as of last year and is being dismantled right now :( – I could start a major rant about it, that would touch the subjects of funding, some people's personal pride and good science vs. fashionable science.
Recessions will also hit even harder - when the next grant cycle hits in the winter/fall, a lot of good teams are going to get screwed. I really hate the inconsistency and the waxing and waning - fwiw, there were times my team just grabbed grant money and spun wheels on old research, so it's not just that the money dries up easily, I don't think there's good accountability when the money is flowing either.
As someone with inside knowledge, can you review my reasoning that it fits, and it probably was?
No idea. I left that particular lab a few months after I graduated which was 8 years ago.
Would we be able to predict one with reasonable precision  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"
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.
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.
N2+O2 -> dissociated N and O plasmas -> NO2
Which means the air might become not breathable.
(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.
Yes they did. It was Arthur C. Clarke's "The Star". And it was "The Twilight Zone" (1980s version).
While the TV episode was interesting, the short story itself is much better. I highly recommend it.
The story was in the "The Nine Billion Names of God" collection. The title story is also interesting in its religious focus.
It's a matter of when it gets to Fe56 and exceed Chandrasakhar limit
Why is that?
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).
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.
Why do people keep fretting about Betelgeuse?? No, it's extremely unlikely it will harm earth when it goes nova: https://arxiv.org/pdf/1406.3143v2.pdf
> When this supernova explodes it will be closer than any known supernova observed to date, and about 19 times closer than Kepler’s supernova. Assuming it explodes as an average Type II super-nova, the optical luminosity will be approximately -12.4, becoming brighter than the full moon.
Science reporting is so very bad.
Would we know if we were sucked into an alternate timeline via that kind of science? Would it matter to us? Could we change it?
I'm sure there's a YA novel in there somewhere.
> Briefly stated, the Gell-Mann Amnesia effect is as follows. You open the newspaper to an article on some subject you know well. In Murray’s case, physics. In mine, show business. You read the article and see the journalist has absolutely no understanding of either the facts or the issues. Often, the article is so wrong it actually presents the story backward—reversing cause and effect. I call these the “wet streets cause rain” stories. Paper’s full of them.
> In any case, you read with exasperation or amusement the multiple errors in a story, and then turn the page to national or international affairs, and read as if the rest of the newspaper was somehow more accurate about Palestine than the baloney you just read. You turn the page, and forget what you know.
– Michael Crichton (1942-2008)
2. Reasonably solid understanding and low risk notwithstanding (Beteleuse, at 300 light years, is well outside the 50 l.y. danger zone), some people will harbour some uncertainty, warranted or not.
3. It'll still be the biggest pop in the neighbourhood for a while.
> a very close supernova could inflict massive harm to life on Earth
...but they fail to mention how close this "very close" is. I assume 700 light years (Betelgeuse) is a little bit far away to qualify? As a total amateur in astronomy/astrophysics, I would assume that if there were any "very close" stars that are massive enough to go supernova, they would already be known?!
Updating with link: https://phys.org/news/2020-08-hubble-betelgeuse-mysterious-d...
My "worry" was based only on losing one of the nicest stars in the Heavens, although a certain excitement of the idea at the same time.
The gas arrived here 2.5 million years ago. According to https://en.wikipedia.org/wiki/Local_Bubble it seems that the Local Bubble was created 10-20 million years ago by a supernova, and we've been traveling through an area currently occupied it for the last 5-10 million years.
If we've been traveling through that region for 5 million years, and the bubble is expanding as fast as we are moving (and we are moving at a pretty good clip), then we would have encountered the edge of the bubble 2.5 million years ago. Which would be exactly right for that to be this.
And it is hard to imagine that there has been another supernova near us that it could have been, without it having left obvious signs of its existence. So Occam's razor says that this has to be right. The supernova that we know from astronomy had to happen near where we are now is the one that dumped detectable amounts of material on us 2.5 million years ago.
Edit: Here's a more recent paper - https://link.springer.com/referenceworkentry/10.1007%2F978-3... :
> "More detailed models for the origins of the Local Bubble have found that it requires anywhere from 3 (Smith and Cox 2001) to 20 (Fuchs et al. 2006) SNe to create a bubble with the correct characteristics in terms of size, pressure, and emission characteristics."
Astronomically and geologically an eyeblink.
Not saying this paper isn't good or anything, just that extrapolating a supernova from a few atoms of an isotope of a metal seems... a long fetch. Though probably better than nothing.
As for direct evidence, I know what you mean. There so way to observe the supernova, but how often do the jury get to watch a murder happen on film? Yet we still convict murderers.
There are assumptions in play, but I doubt they are the ones you are thinking of.
The two main ones are that physics is the same everywhere, and physics is the same all the time. We have no way to say if these assumptions are correct, but we don't have evidence that they are wrong and we do have observations that are consistent with them being correct.
If we take those two assumptions as true, then astrophyiscs is squarely in the middle of the model and measure of hard sciences.
Modelling in particular is wide open for speculation, but there is no reason to think speculative models will be maintained if they are not consistent with measurement. Even the simplest speculative models necessarily have falsifiable and testable claims - if they don't then they don't say much about how the world is.
The nature of astrophysics means that we are able to test and measure in so many ways: near and far, in the present and in the past, atomic scale and galaxy scale. As long as we hold those two assumptions above, we have a lot of evidence and reason to believe our current astrophysical models of the universe.