"a 300,000-year decline in biodiversity leading up to the Devonian-Carboniferous mass extinction"
Is this a real thing? I ask, because paleontologists have had a bad record of interpreting statistical samples around an event. I.e. misinterpreting the mean interval between the last recorded fossil before an event as evidence of 'gradual extinction'.
There is never a bad time to plug Egan on HN. Diaspora is one of his novels around just this topic. If you decide to read it, strap in, you're going for a mind bending ride.
https://www.goodreads.com/book/show/156785.Diaspora
If I remember correctly part of the book is set in a universe with 6 spatial dimensions - and that's possibly one of the relatively straightforward parts....
Another recommendation for this book - I am pretty sure its my favorite fiction novel and I have read it many times. So many interesting and thought provoking parts.
Ill chime in and say that Egan is my favorite author alive right now. He is absolutely producing the best hard sci-fi there is and I have consumed everything he has written that I can get my hands on.
I would also suggest reading Permutation City and the Clockwork Rocket trilogy by him.
The first chapter is utterly uninspiring. I almost put the novel down due to the cheesiness of the cyberspaceness of it.
Well thank goodness I didn’t. This novel was eye opening as a treatise on small and large scale mortality. One of the most thought provoking pieces of science fiction out there.
I've not read Diaspora, but I have read Schild's Ladder. I found it difficult to follow in parts ( the science explanations ) but some of the themes it touches on are absolutely fascinating. Fans of hard science fiction novels will enjoy.
It looks like there's no risk from this now as there are no supernova candidates near enough to have that strong an effect. With stellar drift though. That could change in the course of tens or hundreds of millions of years with stellar drift.
What could we do to mitigate this though. Would enclosed habitats, greenhouses and pastures covered by UV blocking screens be enough to maintain habitability and a sustainable agriculture?
> That could change in the course of tens or hundreds of millions of years with stellar drift.
Not worth worrying that much about it then - in a mere billion years (IIRC) the sun's output is predicted to have increased enough that it's unlikely liquid water could exist on the surface of the earth, effectively ending most life. Though it's possible that the level of CO2 in the atmosphere will have dropped enough to make photosynthesis impossible for most plants in around half that time.
So we only have about 500 megayears to both attain a K2 scale civilization and find a way to use that power to protect our cradle world (or work around the extinction of life as we know it). Got it. No pressure.
Bear in mind that our species has only existed for a rough upper limit of 500 KILOyears. The first electric motor was built only ~200 years ago, and we've only been technically spacefaring for ~60 years. We went from first heavier-than-air flight to first space station in 70 years.
Our species has a thousand times our current age to figure things out. To unironically quote Dennis Reynolds from It's Always Sunny: we haven't peaked. We haven't even begun to peak. (https://www.youtube.com/watch?v=tS7ifk26tJc)
I’m afraid I don’t see it that way. Technologies don’t improve exponentially for ever, they follow an S curve. The physical properties of the universe are fixed and finite. Eventually we will discover all the technologies that are practical, and we may not be all that far from doing so. Maybe only a few hundred years, and we may be quite far along the S curve of some of the best of them.
While I think there is an "S" curve, I see we have quite a lot more to learn, much longer than a few hundred years' worth. I'd say more on the order of hundreds of millennia more at a minimum, because the scales I see possible are so vast. My metric is where we are on the Kardashev scale, how resilient we are to extinction-level events, and our time horizon. The ultimate "we're pretty close to knowing all the practical stuff" level being figuring out how to work around the entropic end of the universe. I count indefinite life extension among the practical tech tree, and once we accomplish that, the range of "practical" also expands.
Even before all that, we're nowhere close to various practical limits we've calculated as theoretically possible in energy extraction, energy conversion, energy conservation, matter properties (compression strength, tension strength, torsion strength, and so on), computational density, information density, etc.
For most of our species' history in geological time, we've barely edged over from sentience to sapience. On that scale, we're still at the boundary layer edge, and have yet to really delve into and establish ourselves within the time stream into sapience.
At that point, and with that much time, and assuming we live that long, I imagine humanity could park a larger asteroid slightly outside of Earth orbit to gradually grow Earth's orbit outwards. Of course that would take a while, but a "while" is a relatively small amount of time when you're talking hundreds of millions of years.
My guess is that we gonna move to the planets of the solar system farther away from the sun until we reach the last one (Neptune?), then we will make some attempts to go to the next closest remaining star, attempts that will probably fail.
There are no massive stars capable of causing a damaging core collapse SN near the Earth.
However, there could be binary white dwarfs capable of causing a "double degenerate" type I SN, unless recent data has now ruled that out. As of 2002 there were estimated to be ~50 undiscovered white dwarfs within 20 parsecs on our solar system.
The Gaia data have found all white dwarfs out to at least 100 parsecs, I believe. There are some double degenerate pairs within 20 parsecs, although I don't know how short the orbital periods are (probably not very).
My understanding is that this only applies at long distances. The center of the galaxy can only block things farther away than that (10s of thousands of light years or more). The kill distance is very close at 25 light years, and stars must be quite big and bright to go supernova.
You and I both know that any event that is 1000 years away nobody will put any effort into protecting against today...
And in 1000 years, humans will have forgotten the XRay blast (do you remember the mysterious plague of 1020AD where lots of people died of cancer? No - didn't think so...), and therefore won't prepare.
>do you remember the mysterious plague of 1020AD where lots of people died of cancer?
I'd love to have a source on this? Particularly in relation to cancer rates at the time? I googled but the only thing I could find was a ref to an outbreak of bubonic plague in germany in 1022AD.
We can see very large populations of sun like stars, and there are no observations of this kind of behaviour, so it seems unlikely. The large full sky survey telescopes coming on-line in the next few years will rule this out our in after a decade or so though. If billion sun like stars are watched for five years at least fifty should pop in a micro nova if the theory has any legs.
If this is accurate, then it raises the question of whether the Sun is inherently and always less active or whether it just happens to be quiet while human civilization has arisen.
Watched enough 'PBS Space Time' to not be illiterate, but still a CompSci background so take my physics with a huge grain of salt. ;)
Is there some way we could tell a distinction between a local event and a long range event with a method (for example: an alignment of particles or minerals in rocks in a particular direction)?
It's great to see articles like this. but I encourage people to treat things like this, and the other thread making rounds about how all the stars that have been made are most that will ever be made as having a chance of being correct at 0.000001%. Not that this percentage isn't an amazing breakthrough, but just don't turn this into - the debate is settled in 5 years.
https://www.pnas.org/content/early/2020/08/17/2013774117