"Well whatever it is, we probably have 1000+ years to save ourselves right?"
No. That time has already passed. If we see signs that the star will go nova "in one year", we have one year, not 1481.
The popular idea that we see "the past" in the sky is not really the best way to think about it. It is far more accurate to say that there is no such thing as "the" present, and what we see in the sky really is our present. The view that we're seeing "the past" is ironically perhaps less sophisticated than the more naive idea that it is simply our present we are seeing in the sky. (And at the moment, there aren't any other "presents" that we much care about.)
The thing that really saves us is that even supernovas that far away can't really hurt us because of the inverse square law. A quick Google search shows one site estimating that a supernova would have to be 50 ly or closer or so: http://www.howitworksdaily.com/could-a-supernova-destroy-ear... Something would have to be beamed specifically at us, and the only natural phenomena I know that can do that are black holes and pulsars, neither of which seem to be what is at that star, and probably still wouldn't be powerful enough to hurt us at that distance.
From an intelligent life angle, what would really save us is that, aside from a number of planets to observe, we haven't really been all that interesting until the last 100-200 years; when we started actually emitting signs of intelligent life in to space.
Ah, but this is only true about we, humans rather than earth/solar system.
It cannot be excluded that other sources of radio have been around here in the past :)
It also assumes that outside observers have the same difficulty understanding the make-up and probable evolution of a system as we do. If they were able to observe that Earth would have some properties they were interested in, or would be a likely candidate for such, then they wouldn't need us to announce our presence to guess it.
IMHO the aliens will not be specifically seeking life that is intelligent. Singularities and interstellar traveling alien civilizations share a problem. If one is in essence immortal the only purpose that can endure forever is the pursuit of new knowledge. Even if alien entities are able to learn all there is to know about all the other sciences, biology will be inexhaustible as the novel patterns that can be produced by evolution are effectively infinite. The biosphere of just our planet where the latest estimates are that there are a trillion species if you count all the microorganisms, probably contains more information than all the lifeless planets and stars in the galaxy combined. The aliens will value biodiversity more than we do. And if they arrive they will oppress us "only" to the extent required to counteract our propensity to cause species extinctions (including our suicidal alteration of the planet's climate). I actually would prefer that the Singularity or the aliens arrive sooner rather than later as I have less and less hope of our species getting its act together on its own.
>> biology will be inexhaustible as the novel patterns that can be produced by evolution are effectively infinite
But why do you assume they would be interested in observing the patterns that actually have been produced, instead of running high-precision evolutionary emulators that can generate patterns that could be produced at a much higher rate, and maybe even some automated filters to condense it down to "interesting" stuff? It's still knowledge, and there's no innate value scale for knowledge which says that things that have "actually happened" are more valuable.
In fact, how's that for Fermi paradox? Civilizations that are sufficiently technologically advanced to communicate, much less travel, across the stars, are also sufficiently technologically advanced to simulate the things they are interested about and get answers faster that way.
Basically, the end result of any civilization is creating, maintaining and expanding a simulation of the universe. Which, of course, goes recursive...
Thermodynamics still limits what you can compute and, given the output of a single star, you're still limited in what can be computed.
But I think it's a mistake to try to characterize any civilization by a single motivation. People on Earth do things for many different reasons and I think we should expect the same of alien civilizations even if single motivations tax our imaginations less. The questions is if any of the motivations driving a stellar civilization would be enough to prompt the establishment of colonies. I don't think you can say that the answer will be 'no' reliably for every civilization that might arise and it only takes on to colonize a galaxy in short order (by cosmic standards). Hence sophisticated life is probably very rare.
In a similar vein, a possible Fermi paradox solution would be that civilizations sufficiently technologically advanced to travel between stars are also advanced enough to develop good VR and learn which buttons of their brains to push, so they all end up stuck in virtual worlds, or even wireheaded.
A counterargument to that would go along the the similar lines as to why we don't, and can't, resolve wars by e.g. playing chess (or StarCraft). Even if all nations mutually agreed that the shall will be won bloodlessly by some other kind of competition, the first nation to nuke its enemies would be a winner. In conflict situations, you want to seek as much advantage from the "most real" reality as you can get. So, in your recursion example, you'd travel up the call stack...
You can't just wave a wand called "emulation" to hypothesize whatever speed, precision, or rate of calculation you want. Emulators are physical objects and you'd need to show that it's possible to build an emulator that calculates the same amount of information as the Earth's biosphere, but faster, more precise, etc.
Then, once you have the attributes of that emulator, you'd have to calculate how long it would take that emulator to deliver the same information that can be harvested today on Earth with simple observations. And even if it completed, how would you confirm it is indeed the same information without traveling here to check?
The energy budget would be immense of course, but heat management might be the limiting issue on how fast it can run. It's hard to dump heat into space.
I'm not intending to argue one or another about hypothetical god-like alien civilizations. It's just a pet peeve when programmers make open-ended claims about simulations or emulations without considering physical constraints. We tend to think of electronic computers as powerful, but their information handling capabilities are quite slow and diffuse compared to what biology has produced on Earth so far.
Thinking that pursuit of knowledge is only activity for immortal is naively idealistic.
Elimination of of all life not like me. Or simply eliminate life that might singularity and become a threat. Even if, who's to say one aliens pursuit of knowledge latest experiment dose not require and earth sized amount of raw materials.
Our aggression reflects the zero sum physical resource context of our evolutionary past. Knowledge in contrast grows fastest through cooperation. As power including the power to defend oneself grows with knowledge, knowledge seeking entities will quickly evolve to maximize cooperation. And as many have pointed out, unlike most of our sci fi, it is very unlikely for two alien civilizations to meet where their technology levels are similar - one will be permanently vastly advantaged over the other. Aggression will be pointless - the pecking order will be obvious. As to your last point I am sure lifeless planets will do for any experiments.
My unprovable assumption is that only beings who value knowledge and cooperation highly enough will get to the point of crossing the difficult technological threshold of achieving singularity or space travel. I think the more likely Achilles heel for my scenario is sexual selection - the trap that perpetuates selfish behavior in both sexes even when there is no resource scarcity. Even in this, humans at least are sometimes able to escape the trap by being meta enough to see kindness as strength and beauty. I think the fastest, and most likely first, route to our singularity will start with reverse engineering one human mind, and I will hold onto hope that that mind will hear the call of light, and the truth and beauty feedback loop will be unstoppable. It helps that I also believe that as information increases, morality converges on a process for maximizing the long term preservation of information (where on this planet, human minds are the most information dense and therefore the most valuable things we can preserve). /end sci fi sermon
An anthill-like species can value cooperation among themselves without necessarily valuing knowledge for knowledge's sake - imagine the Hive Queens from Ender's Game, or MorningLightMountain.
Hmm, that's actually not true. For example a spectroscopical analysis of the composition of be earth's atmosphere would reveal very unusual properties which would be a sure telling sign of photosynthesis, and that has been occurring for billions of years.
Yeah, it looks like a supernova 1500 ly away might produce enough gamma rays that we could actually measure their effect on the ozone layer but not enough that it would be concerning.
Unexplained dimmings do give rise to the question of "Is it about to explode" but we have a good sense of how often large explosions occur in galaxies because they're so obvious and so I suppose I shouldn't be concerned about natural phenomenon. And given the potential expansion rates of being who could create megastructures like this our priors on that explanation have to be pretty low.
So what's the risk if it turns supernova in one year? As you say, it's 1500 ly away, not <50.
You sound way more expert on this than me (I had no idea lightyears had a notation, ly, nor that supernovas are dangerous to us as far as 50ly away), so I'll assume what you say is accurate, but I still see no imminent threat.
I'm also not suggesting we'd have the full 1481 years, since we don't see what's presently there but what was there, but as long as the phenomenon doesn't travel at the speed of light (and it doesn't, or we would be experiencing it already, since we can observe the effect) we still have time.
Finding information on this appears to be kinda hard, but it looks like the best estimate for the 'kill radius' of a supernova (i.e. will cause mass extinctions) is 30 light years. So this is about two orders of magnitudes away, which means the effect will be two orders of magnitude lesser.
Eta Corina is a double star containing at least one hypergiant that's going to go supernova any epoch now, so it gets studied a lot. It's 7500 light years away and I believe it's judged not to be a threat, although there may be ozone layer damage and it's probably not healthy to be an unshielded astronaut.
However supernovae appear to emit gamma ray bursts along their axes. These can travel very large distances. Eta Corina's isn't point our way, but Tabby's Star? Who knows. 1500 light years is basically point blank range for a GRB, so if one is coming our way that would be very bad news. Like, worse than mass extinction grade bad news.
"So this is about two orders of magnitudes away, which means the effect will be two orders of magnitude lesser."
Inverse square applies here; moving 100 times farther away makes the effect 10,000 times less.
(I have to say it "applies here" because people sometimes overapply the law. It only applies when something is spreading out in an even sphere. However, that applies to supernovae, or at least close enough.)
You're right that I neglected gamma ray bursts. But it also doesn't seem like this star could be building up to that, since it requires conditions not evident there. (I'm just following up on my point, not implying that you claimed otherwise.)
I believe the most powerful gamma ray bursts, the ones that are powerful enough to strip away our atmosphere at thousands of light years, are caused by superluminous supernovae (aka hypernovae) and weaker GRBs like the ones we usually see are caused by type 1c and 2b/n supernovae, although it is unclear whether they are different or closely related to hypernovae. The latter create long duration gamma ray bursts which last a lot longer than the usual burst and carry significantly more energy.
No. That time has already passed. If we see signs that the star will go nova "in one year", we have one year, not 1481.
The popular idea that we see "the past" in the sky is not really the best way to think about it. It is far more accurate to say that there is no such thing as "the" present, and what we see in the sky really is our present. The view that we're seeing "the past" is ironically perhaps less sophisticated than the more naive idea that it is simply our present we are seeing in the sky. (And at the moment, there aren't any other "presents" that we much care about.)
The thing that really saves us is that even supernovas that far away can't really hurt us because of the inverse square law. A quick Google search shows one site estimating that a supernova would have to be 50 ly or closer or so: http://www.howitworksdaily.com/could-a-supernova-destroy-ear... Something would have to be beamed specifically at us, and the only natural phenomena I know that can do that are black holes and pulsars, neither of which seem to be what is at that star, and probably still wouldn't be powerful enough to hurt us at that distance.