Happy New Gregorian Year!

human/robot merger to create bodies that are indestructible?

If we colonize many star-systems, there would be a great diversity of 'humans'. Their divergence would be inevitable as colonies are established and new technologies are invented. Physical and mental differences might stem from technological modification, evolutionary adaptations to alien worlds over vast periods of time, hybrids of our Earth-animals or even hybrids of homo sapiens sapiens and any aliens we encounter (barring any obvious biochemical differences of course). And that isn't even considering the virtual entities and AI's we'll have made. Point is, there won't be a homo sapiens sapiens anymore - we would have been bred out long ago. Instead, a menagerie of our descendants and modified cousins will inherit the stars. If we ever get there and somehow establish a star-civilization of any appreciable size .

I kind of want to see the two supermassive black holes merging in the galaxies and see what that would result in.

Yeah, me too.

How long have Saturn's rings lasted?

It depends what Ring-formation theory you believe and how it is interpreted. The most commonly-held theory is that of the ring being the result of a moon disintegrating during the Late Heavy Bombardment about 4 billion years ago. This moon was thought to be a Mimas-sized planetoid about 800km in diameter, but more recent theories suggest it could have been a Titan-like satellite.

Recently though, data received by the Cassini probe tell us that a majority of Saturn's rings are quite young - a mere 100 million years old, and have been created and maintained by micrometeorite, comet and icy-moon detritus sucked in by magnetic flux in Saturn's radiation fields. 

human/robot merger to create bodies that are indestructible?

If we colonize many star-systems, there would be a great diversity of 'humans'. Their divergence would be inevitable as colonies are established and new technologies are invented. Physical and mental differences might stem from technological modification, evolutionary adaptations to alien worlds over vast periods of time, hybrids of our Earth-animals or even hybrids of homo sapiens sapiens and any aliens we encounter (barring any obvious biochemical differences of course). And that isn't even considering the virtual entities and AI's we'll have made. Point is, there won't be a homo sapiens sapiens anymore - we would have been bred out long ago. Instead, a menagerie of our descendants and modified cousins will inherit the stars. If we ever get there and somehow establish a star-civilization of any appreciable size .

I kind of want to see the two supermassive black holes merging in the galaxies and see what that would result in.

Yeah, me too.

How long have Saturn's rings lasted?

It depends what Ring-formation theory you believe and how it is interpreted. The most commonly-held theory is that of the ring being the result of a moon disintegrating during the Late Heavy Bombardment about 4 billion years ago. This moon was thought to be a Mimas-sized planetoid about 800km in diameter, but more recent theories suggest it could have been a Titan-like satellite.

Recently though, data received by the Cassini probe tell us that a majority of Saturn's rings are quite young - a mere 100 million years old, and have been created and maintained by micrometeorite, comet and icy-moon detritus sucked in by magnetic flux in Saturn's radiation fields. 

Right, evolution always results in the destruction of the evolving species.  Even if we unfortunately always remain on Earth, evolution into a new species is inevitable.  Studies have even shown that evolution is occurring faster now than it did in the past.  Something I think about with bemusement is how the differing gravity would cause humans to evolve differently on different worlds.  Not only that, but staying in space for any extended period where gravity is vastly different from what it is on Earth would require extensive reconditioning for those humans to be able to live on Earth again!
Something fascinating about Saturn's moons and rings is how some moons "shepherd" the rings, that is keep them in place.  Also, some of the smaller ringlets cross over each other several times.  I wonder if there is a mathematical relationship between the distances from Saturn to each ring and ringlet as well as between the rings and ringlets themselves.  Remember Bode's "Law" that shows a nice pattern for the distances between the planets and from each planet to the sun?

Super weird coincidence, a NASA person just came on TV literally minutes after I posted this talking about the Cassini mission recently finding out that the inner ring on Saturn is raining down on the planet, and based on this, it's estimated that ring will only last another 100 million years!

I wonder if there is a mathematical relationship between the distances from Saturn to each ring and ringlet as well as between the rings and ringlets themselves.  Remember Bode's "Law" that shows a nice pattern for the distances between the planets and from each planet to the sun?

https://www.space.com/30197-saturn-rings-math-rule.html

Thanks, very interesting and to be expected!  The NASA person also said that he expected some biosignatures for extraterrestrial life either inside or outside our solar system to be found within the next 20 years.  I hope it's actually inside our solar system because (unless it has a common source to ours) having two bodies with some sort of life on them in the same solar system greatly increases the chances of life elsewhere too.

The NASA person also said that he expected some biosignatures for extraterrestrial life either inside or outside our solar system to be found within the next 20 years.

I suspect that "biosignature" would be a "may have been cause by life".  So, if it's inside our solar system, we might have ways to verify.  Otherwise, such claims would likely be unverified, or unverifiable, for a very long time.  Anyway, I look forward to see data gathered on the atmospheres of exoplanets which seems doable in the coming decades.

The NASA person also said that he expected some biosignatures for extraterrestrial life either inside or outside our solar system to be found within the next 20 years.

I suspect that "biosignature" would be a "may have been cause by life".  So, if it's inside our solar system, we might have ways to verify.  Otherwise, such claims would likely be unverified, or unverifiable, for a very long time.  Anyway, I look forward to see data gathered on the atmospheres of exoplanets which seems doable in the coming decades.

I see that water has been detected in the atmosphere of 51 Pegasi B.... but is that a uninhabitable planet because it's a gas giant?
I also read somewhere that water has been detected in the Trappist-1 system exoplanets' atmospheres?
To be honest I'm most excited about the Tau Ceti system right now, it has a sunlike star and earthlike exoplanets (two of them in the habitable zone!)  I think we should put some focus there.

Water is not a biosignature, but we can't expect to find any biosignatures unless there is also water.

but we can't expect to find any biosignatures unless there is also water.

In most cases, but exotic life could exist without it. We would however have some difficulty recognizing it though, so yes, lets just stick to what we think is more likely. H₂O thalassogen solvent-based life .

I see that water has been detected in the atmosphere of 51 Pegasi B.... but is that a uninhabitable planet because it's a gas giant?
I also read somewhere that water has been detected in the Trappist-1 system exoplanets' atmospheres?
To be honest I'm most excited about the Tau Ceti system right now, it has a sunlike star and earthlike exoplanets (two of them in the habitable zone!)  I think we should put some focus there.

Water has been detected in the atmospheres of a lot of planets with our current detection methods. These exoworlds range from Superjovian hot-gas giants to scalding superearths. None of them are very likely to host Earth-like life beyond extremophiles. The same goes for Tau Ceti e (Tau Ceti f only recently migrated into it's current orbit less then a billion years ago). While this exoplanet resides in a scientifically interesting system, it's characteristics make it an unlikely abode for life of any sort. Maybe we could terraform it in the future, but it would require a lot of effort on our part, if we ever go there.

The NASA person also said that he expected some biosignatures for extraterrestrial life either inside or outside our solar system to be found within the next 20 years.

I suspect that "biosignature" would be a "may have been cause by life".  So, if it's inside our solar system, we might have ways to verify.  Otherwise, such claims would likely be unverified, or unverifiable, for a very long time.  Anyway, I look forward to see data gathered on the atmospheres of exoplanets which seems doable in the coming decades.

I see that water has been detected in the atmosphere of 51 Pegasi B.... but is that a uninhabitable planet because it's a gas giant?
I also read somewhere that water has been detected in the Trappist-1 system exoplanets' atmospheres?
To be honest I'm most excited about the Tau Ceti system right now, it has a sunlike star and earthlike exoplanets (two of them in the habitable zone!)  I think we should put some focus there.

If life could evolve to exist and float permanently in the atmosphere of a relatively calm gas giant, then there's a slim chance life might exist [s]on[/s] [s]in[/s] [s]around[/s] gas giants.

then there's a slim chance life might exist on in around gas giants.

Sagan hypothesised the existence of floaters, sinkers and hunters in such atmospheres, possibly reaching sizes in the kilometers.

Somewhat off topic, I find it fascinating that the northern coast of Greenland was inhabited most of the time for a few millennia until the 1st century BC.

What technology level were these peoples at? Were they roughly equivalent to the Inuits?

Also, did you happen study the Norse colonization of the southern coasts of Greenland? The behavior of the pioneering Scandinavians there was a poignant reminder of the dangers of non-adaptation to a changing environment, together with rigid adherence to a political system unsuited to the new land.

Trade with the Norse Greenlanders might have stopped for several reasons, and without that they were probably doomed.  Climate, yes, but this was a remote place and perhaps simply not worth the effort to keep going to (regardless of climate).

Climate seems likely. My knowledge of this comes from the work of Hans Rosling when he used these colonies as an example of a dogmatic society's issues with adaptation. So yes, the climate cooled a little, rendering the colonist's original agricultural and hunting techniques ineffective at best. For religious reasons, they refused to use the native Inuit's methods of survival because it was too pagan. It is also possible they became inbred due to a smaller population. Coupled with a lack of political interest in the region, and they died out. As I recall, the last record of those colonies was a wedding taking place in Hvalsey. Rosling used them to illustrate that we as a society should be ready to change our lifestyles to further our survival should the need arise (as it is now with climate change).

Somewhat off topic, I find it fascinating that the northern coast of Greenland was inhabited most of the time for a few millennia until the 1st century BC.

What technology level were these peoples at? Were they roughly equivalent to the Inuits?

Also, did you happen study the Norse colonization of the southern coasts of Greenland? The behavior of the pioneering Scandinavians there was a poignant reminder of the dangers of non-adaptation to a changing environment, together with rigid adherence to a political system unsuited to the new land.

What was their political system?  Didn't the Vikings have some kind of navigational stone they used during their voyages? I had read they made it to North America- Labrador and possibly as far south as Cape Cod?  There were even some Viking artifacts found in Minnesota!

The inuits were "too pagan?"  That's ridiculous if they thought that, ugh another reason for me to dislike religion lol- especially monotheistic ones.

I think the Mayans also died out because of a change to a much drier climate (persistent La Nina conditions.)

Also, about prospects for life, do you put the Trappist-1 system near the top?  But since it's a red dwarf, what sunlike stars would you say have planets that are near the top of the list?

And I saw floaters being mentioned as possible signs of life above gas giants, can the same be said for life existing in the atmospheres of cool brown dwarfs?