Where we are in space

Here's something you don't see all the time that gives a little perspective of "where we are".  The photo is a spiral galaxy more or less similar to the Milky Way seen almost exactly edge on. Think of it as a stand-in for our Galaxy. Then the diagram, obviously not at all to scale, depicts the angle of the plane of the solar system, about 66° to the plane of the Galaxy. (In reality, the Solar System would be invisibly small at this scale, as the Sun is but one of nearly 300 billion stars in the Galaxy.

  We are about 27,000 light years from the center, and the disk as seen in this image would be about 85,000 light years in diameter in the Milky Way. The Sun is located in a spur of one of the spiral arm, and its orbit and position with respect to the central "bar" (the MW is a "barred spiral" type galaxy) is shown in the image below.

  

Star Trek and Reality

 I felt a little guilty signing up for Paramount+ (formerly, it would seem, "CBS All Access"), just to watch Star Trek Discovery, then cancel. At least I did pay them for one month. And in truth they don't have much else on there I care to watch. Star Trek is an indulgence. It's both surprisingly good and really, really awful at the same time. As plausible science fiction, it gets the big things totally wrong (and doesn't really try or care about them, I would say), but gets a lot of details intriguingly plausible. Pace Albucierre fans (if you watch him actually describe his theroy on YouTube, you quickly realize that a "real" warp drive would require massive amounts of energy and/or massive amounts of "negative energy," which, in terms of practical physics, simply isn't a thing). There is no plausible scenario for developing widespread faster than light travel. It's a science fiction "Deus Ex Machina" because stories without it tend to be dull. But in all the wide universe, including beyond the Timelike horizon (outside of which information and photons (same thing) can never reach here from there), there is no such thing. We can be quite sure of that for two reasons. FTL violates causality, which seems to be a fundamental pricniple of nature, and, Fermi. If civilizations capable of this technology existed, even if they were really really rare, the universe would be a very different place, because locally, on the scale of galaxies, and, especially, in the past when the expansion of the universe hadn't progressed as far, anyone capable of FTL could colonize vast tracts of space in times only minute fractions of the ages of the stars and planets that gave rise to them. The universe may be yet young, at 13.7+ billion years, but if FTL is possible and even one in a thousand galaxies has given rise to it sometime in the last few billion years, "they" would already be everywhere. And they're not. (This may not be obvious, but if you really think it through, it's pretty ironclad).

Transporters also create all kinds of problems. If you've ever read Daniel Dennett on consciousness and what might constitute the instigation and continutiy of particular self-awareness (i.e., the sense of being "me" and not an abstraction), you would never get in one of those things even if they did exist. Captain Kirk gets in. "A" Captain Kirk walks away from the transport site on the planet and blithely believes himself to have just been transported. But you will never convince me that the first Captain Kirk is not dead, and the second Captain Kirk is not a remarkably accurate simulacrum, with its own instigation of consciousness at the moment of reassembly. But the planck-time to planck-time chain of causation of one conscious state to the next is broken, and the new Kirk is not the old one. Or so I believe, and it's an issue that is never really dealt with in the fictional universe.

But littler things. The original Star Trek famously anticipated flip phones. In the current shows, people just talk, and the computer network figures out who they want to talk to, sets it all up, and that person hears them. This technology is not only plausible, it's almost here. As is the miniaturization of communicaition devices (including nerual interfaces) will likely mean that a time subcutaneous implant will connect us to the "net" all the time just by mentally activating it. This seemed like wild fantasy 50 years ago but will probably happen in the lifetime of people alive right now.

And medicine. The Tricorder and the ability to use genetic treatments to cure almost anything. While there are numerous fraught issues implicit in these technological developments, it does seem likely that humanity is close to figuring out the language of life, and how to fix things when they go wrong, pretty much perfectly. I've had arguments with people who don't think this is true, but it seems pretty obvious to me that we're heading in that direction. Some of the inevitable consequences of that kind of technology will be pretty dystopian, but it's inevitable.

And the same goes for environmental technology. We have a crisis on our hands right now; we've stressed the planet's resources to a breaking point, and have upset balances that have been in place a long time. Not forever, though. Google the PETM (Paleocene/Eocene Thermal Maximum). Nature has given us (several times) global thermal and atmospheric composition crises at least an order of magnitude worse than this one. And from what I've read of it, I'm pretty sure our species (or a descendant species) would survive such a global catastrophe. And once we have established a presence in space (which we will; there's just no reason not to), we will have learned how to regulate environments and steward the habitability of our home world. THIS, I believe, advanced civilizations, albeit very rare, DO tend to learn to do. Out there somewhere is NOT a Star Trek universe, but there are advanced civilizations that have learned to focus and harness the remarkable adaptation that is "humanlike" intelligence to cohere and expand the living systems of their worlds and create the seeds of a new era of life in the universe that will endure for an unimaginably long time.

Doesn't make for exciting science fiction adventure stories, but the reality is pretty amazing too.

Escape to Space?

I wrote a version of this to a friend with whom I'd had a debate about whether humanity will have to save itself from coming catastrophes by literally escaping into space. This is an idea which I find preposterous on several levels, but I take it seriously and address it, in an admittedly somewhat disorganized fashion.

 

Let me try to lay out my reasons for why I'm so insistent that "escaping" from a "dying Earth" is a hopeless, but in any case implausible, scenario. Obviously, you're entitled to a different view, but I honestly think the case is so overwhelming that only insistence in the face of reasonable inference from facts can lead to any other conclusion. I don't have a "stake" in convincing you of anything, but I'm interested in these issues and think they are of vital importance to humanity's future, so I'm going to try to at least explain why I think the way I do. This is all rather off the cuff, but I've thought about it a fair amount and read quite a lot about the underlying facts, so I'm happy to go into whatever depth you think we can or should.

 

First, why I believe that even if the Earth were so compromised that human survival could be achieved only by transporting a large number of people to some other place, such an enterprise, at any time in the foreseeable future, is almost certainly doomed to failure. As an aside, you seem to be thinking some other planet, but I'm pretty sure if it came to this the attempt would have to be made to build a space habitat in near-to-earth solar orbit. Where materials from the moon and the rapidly deteriorating Earth could at least be used to jumpstart the project. The only plausible scenarios in which I see this playing out involve the collision of an enormous bolide that would literally wipe out life on Earth. Even a Permian level extinction event would probably be better addressed primarily on the surface of the planet, whereas a major solar system wide event, such as a sudden change in the sun's output or the approach of another star or black hole (or dark matter disruptor), would probably be curtains for us at any stage of technological development we're likely to achieve in the next several millennia at least, and technology could not save us. More about what kinds of catastrophes might occur and how we might deal with them later.

 

I'm sure you're familiar with the "Gaia" hypothesis, wherein life on Earth is interwoven in extremely complex reciprocal self-regulating systems that keep the atmosphere breathable, the ocean salinity within a livable range, the carbon cycle regulated so as to keep global temperatures and life-chemistry (nutrients) at livable levels, etc. There's nothing mystical about this, it's just that evolution works on many different levels, and the highest tier is planetary ecosystem. Natural selection tends to optimize aspects of even this system, because the optimizations succeed where the poorer adjusted systems fail. I mention all this because it has proven to be essentially impossible, with anything like present technology, to replicate these kinds of reciprocally self-regulating systems artificially on small scales. In other words, without a lot of energy and supplies from home, it is... so far... impossible to create a self-sustaining colony in space. Attempts to do this in controlled experiments failed miserably in a fairly short period of time. (Biosphere I and II).

 

OK, sure, eventually, it's undoubtedly possible, but even with all the resources of a thriving civilization, the creation of sustainable artificial habitats has proven to be beyond our capability. Incidentally, the example of something like the USS Enterprise (not that such exists), or an O'Neill space habitat, which seems like a feasible enterprise, are not counterexamples. Such habitats would be dependent on supplies, personnel, technology, assistance, and synergistics from and with the planetary civilization that created them. Sure, again, eventually, we will build things big enough and understand well enough how to ensure their independence and long term stability. But it appears quite clear to me that we are nowhere near this level of technological ability or understanding at present, and that if faced with the immediate necessity to construct a sustainable habitat with no input from Earth anytime in the foreseeable future, such efforts would almost certainly fail. Happy to talk about this in greater depth, but my conclusion is this: if our species has to abandon Earth at any time in the next few thousand years due to catastrophic failure of the habitability of our planet, we are simply doomed, full stop. We cannot possibly manage to replicate a planetary ecosystem in miniature without resources and supplies from a planetary civilization. In the bolide scenario I mentioned, we would surely try, but I think our chances of success are extremely bleak.

 

As far as reaching already existing planetary biospheres on exoplanets goes, there are myriad problems that make this completely nonviable in the foreseeable future. Not least of which is that, except possibly for tiny automated probes, we are nowhere near the capability of constructing interstellar vehicles that could transport large numbers of people. In any case, there is no reason to believe from what we know of exoplanets that there are any anywhere near the Sun that would be easier to adapt to and live on than artificial habitats, or planets or moons, in the Solar System. We have no evidence that any of them has an oxygen atmosphere, or conditions anywhere near similar to Earth, even if some of them could sustain, potentially, some form of life. Again, eventually, I feel sure humans will venture to the stars, but as a short term survival option, this prospect is completely off the table. Of that I am quite sure.

 

But this is really getting ahead of the main issue, as I see it. Which is this: apart from the bolide or solar system wide catastrophes mentioned, we are more likely to be able to survive an ecological catastrophe on our planet by adapting to it here, on the planet, rather than trying to escape from it. We may use space resources to deal with the crisis, whatever it may be, but the core of humanity that survives, if it does, will remain on Earth.

 

Let's consider some of the possible near term catastrophes that might happen, excluding a killer asteroid of the sun going nova. A less-killer asteroid, including even the Mesozoic/Paleogene extinction level event 66 million years ago, would actually probably be survivable. We would have very little warning of it, and not be able to transport any significant fraction of the population off the planet anyway. Surely it would be truly terrible; perhaps 90% of humanity would perish within a short time. But from what I understand of what happened then, we could harden our habitations in places not actually vaporized or destroyed, and probably manage to survive. Not in space, but on Earth.

 

A worse scenario would be something like the Permian Extinction, which is believed to have been cause by the wholesale poisoning of the atmosphere by massive traps of continental basalt, in what is now Siberia. (There may have been other factors as well). 99% of sea and land based species became extinct. But this kind of thing does not happen overnight; we would see it coming and could start preparing for it, figuring out how to mitigate the effects. Some effort to build space habitats would no doubt be involved, but the great mass of humanity would remain on Earth while our species tried to figure out how to live through such a crisis. Life, including advanced animal life, survived the original event, without the benefit of intelligence or technology, so my bet would be we would figure out how to survive too.

 

The most frequently considered catastrophe humanity is faced with, which we are already in the midst of, is of course the Climate Crisis. Human beings are, in fact, very busily engaged in innovation and technological transformation to deal with this crisis, and I am actually pretty optimistic that we will achieve zero carbon energy technology and transition to sustainable advanced energy infrastructures in the relatively near term (let's say 200 years). There may be some really nasty episodes in the interim, but from what I understand, the chances that this will just run away from us and we will actually face extinction are quite low. As an interesting precedent, consider the PETM (Paleocene/Eocene Thermal Maximum). This event occurred a little under 56 million years ago and lasted about 200,000 years. Probably caused by massive volcanism that raised the CO2 levels in the atmosphere far beyond anything seen since, including the present global increase. Global temperatures rose by 8°C or so (from a higher baseline that the recent Antrhopocene baseline of ca. 1750 AD). Palms throve at the poles. The equatorial regions were in some cases beyond habitability (although not as hot as during the drying out of the Mediterranean, when local temperatures reached as high as 175°F, but that's another story). But here's the point. There was a lot of extinction, but the global ecosystem did not fail. Evolution actually got a kick in the ass, but if humans were somehow transported to that time, we would have been able to rather easily adapt.

 

My point is that, even without the mitigation and control efforts we are already beginning to undertake, Climate Change is not a true mass extinction level event. If it did somehow result in the extinction of humanity, it would self-correct in about 1000 years, but that's very unlikely; what's more likely is that we will respond to it, and deal with it. Escape into space will play essentially no role, although of course space technology will continue to develop.

 

Let me go off on yet another tangent. I regard the evolution of advanced intelligence on earth as just getting started. And it is a fundamental evolutionary development, comparable to the evolution of photosynthesis, oxygen respiration, eukaryotism, sex, multicellularity, or possibly one or two other huge changes in the course of life. Our species is only a vehicle for this change. Just as the first plants no longer exist or have given rise to a whole spectrum of widely diverse descendants, we will give rise to advanced intelligence that is not strictly speaking Homo sapiens, and there is no reason to expect that an adaptation as clearly advantageous as this one will not continue to exist almost literally forever… it will give life the ability and opportunity to survive in places other than Earth in the distant future. I am not talking about that here. I do believe that intelligent beings, probably originating on Earth (and perhaps other places) will eventually inhabit the cosmos in general, and in ways we can scarcely imagine. So things like the eventual loss of the oceans from Earth as the sun continues to heat up, which is expected to occur as early as 800 million years from now, are not relevant to this discussion. Why? Because that is so long a time from now that I believe intelligent civilization will have emerged and be thriving in a vast region of space by then, and what happens to one star, and one planet, however historically significant, will be of minor importance.

 

Anyway, the PETM was the warmest period on Earth, since it happened. Overall, the level of CO2 in the atmosphere was falling pretty continuously since then, and the last 3 million years have been marked by the onset of global ice ages. Partly caused by orbital irregularities, continental positioning, and other factors, but, as various atmospheric and planetary scientists have argued, probably also caused by the gradual failure of the carbon cycle as the Earth ages. Our atmosphere was, until we came along and started burning fossil fuels, actually moving towards a crisis of low carbon. CO2 is essential for plant life, and it is was actually likely, in a few million years, that macroscopic plant life would start failing as a result of ultralow carbon in the atmosphere. But this is a long term trend that would not have affected us that much were it not for our technology. But the point is that, while the Climate Crisis is very real, and if we want to maintain a sustainable world without major disruptions in our societies and civilization, we must deal with it, on a longer term scale, it is an anomaly in a bigger picture that has the Earth's biosphere stressed by cold not heat, low carbon not carbon excess. And in any case, it is not likely to be an extinction level event for our species. (A lot of bad things can happen short of extinction, though, so the technological innovation needed to redress and mitigate the problem is vital). 

 

And the solutions to the Climate Crisis are going to be implemented on Earth, for the most part, not be escaping into space. I think of this as noncontroversial, but if you have a different view, I'd be happy to talk about it further.

 

 

Rubisco, Evolution, and the implications of rational intervention in the future of life

 If you're unfamiliar with the most abundant enzyme on Earth, Rubisco, (upon which essentially all plant and animal life is totally dependent), you might wish to read this. For those who are curious about life, the universe and everything. What is truly amazing is that a long, LONG time ago, nature came up with an OK, but not great, way to fix carbon into the very stuff of life, but it was before there was a lot of oxygen in the atmosphere, so it's not quite good enough at distinguishing CO2 from Oxygen. But humans, whose adaptive intelligence is THE most significant development since the evolution of photosynthesis, are about to dramatically improve the efficiency of Rubisco, after 3½ billion years, by modifying its natural form to make it better at rejecting oxygen and latching on to CO2, which is its function.

I never learned this stuff in school...the importance, function, and name for Rubisco wasn't really understood until about 1980. But it is a truly fundamental aspect of life that everyone should know about in basic outline.

This passage near the end of the admittedly highly technical article is to me the most interesting.

"Even though evolution is generally considered to be a highly creative force, its nature is actually rather conservative. Once a biological solution is found by evolution, the space to explore new evolutionary paths dramatically narrows, as evolution rather tends to work in a tinkering fashion by improving and recombining existing parts and pieces. This pattern is also reflected in RubisCO's history: ....

"With the advent of synthetic biology, however, it becomes possible to realize completely novel biological solutions that are based on rational considerations and not bound by historical-evolutionary constraints. Currently, several ideas are followed to overcome RubisCO's inefficiency with synthetic biological methods: Some approaches aim at replaying the evolution of RubisCO with RubisCO variants [54] or resurrected ancestors [10•], which are placed under strong O2 selection to create alternate RubisCOs that could break the Pareto front of modern-day RubisCOs. ....

"The most radical approaches, however, aim at completely redesigning photosynthetic carbon metabolism. Some efforts aim at realizing a synthetic photorespiration that would allow for additional CO2 fixation and could cover up for RubisCO's side reaction with O2 [56]. ...

"Only the future will tell whether carbon fixation through an alternatively evolved RubisCO, a neo-RubisCO, or RubisCO-independent synthetic pathways will allow us to rewrite or even overwrite the chapter of RubisCO's evolution."

Implicit in this whole discussion is a concept I think is emerging and will become dominant in our civilization before too long. And that is that, whether you think of it teleologically or not, one function of the evolution of humanity is that evolution will become free of the conservatism mentioned in this passage, and truly novel solutions that will allow life to thrive and exist in ways it never has before, in environments far beyond earth in space and time, will come about, with the intervention of human intelligence as a critical factor in future evolution. A Brave New World, which I think will happen whether as individual humans we want it to or not. https://www.sciencedirect.com/science/article/pii/S095816691730099X

A Humble Request

Farflung correspondents, 

Please. I am humbly asking you. Download and listen to the latest Deconstructed Podcast with Ryan Grim (Intercept Media, available anywhere) on the vital importance of HR1/S1, the bills which will only pass with Herculean effort because of the filibuster rules, and which, quite simply, probably mean the difference between whether we are able to restore some semblance of democracy in America or will ultimately lose to the oligarchy/corporate interests who pretty much own the place at present.

If you value democracy and resistance to authoritarian control in our country, you need to understand how vital this is.

Thank you.

 

https://theintercept.com/2021/02/01/deconstructed-hr1-save-american-democracy/ 

What if....?

I had rather hoped that VP Harris would take a radically new approach to being the tie breaking Senate President. Namely, just say, well..... "given the fact that the two parties are tied 50/50, I will simply follow the plain words of the Constitution, and preside over the Senate. All the time. Forget about the "president pro tempore," and organizing rules. I will preside, thank you very much. And you, Senator McConnell, may sit down."

It's never been done before. And, alas, she did not take this step. But I wonder what it would've been like had she done so. She would only vote when there was an actual tie, but as far as I am aware, there is nothing actually stopping her from asserting her constitutional prerogative to preside over the Senate at all times. 

Truly excellent presentation by physicist Sean Carroll on the predicament of American Democracy at the present moment • HIGHLY RECOMMENDED

Farflung correspondents, 

I'm not particularly shy about recommending podcasts and other media presentations, but this one is truly special. It is one of the episodes of the excellent Mindscape podcast presented by the theoretical physicist Sean Carroll. But it is not in any way about physics.
 

https://www.preposterousuniverse.com/podcast/2021/01/11/129-solo-democracy-in-america/

 We've all heard a ton of commentary on the events of 1/6/21 and the threat to our democracy, etc., but this one, which is incredibly thoughtful and explicitly takes the point of view of discussing our predicament as if explaining it to people in the distant future, is just excellent and not to be missed. Carroll is a physicist, but he's also a philosopher and polymath, and what he says, and the people he interviews, are almost always incredibly interesting and well-informed. In this case, he does all the talking himself, but what he has to say should be given some thought by literally everyone living through this moment in time in the history of the world. 

Thanks for considering giving it your attention.

David 

Fwd: January 6, 2021

Even if you've been following the horrific events of yesterday's insurrection and coup attempt, this "first draft of history" by America's historian, Heather Cox Richardson, is worth reading, and I commend it to all my farflung correspondents. We are in an inflection point. If we get through the next two weeks, we may well be in a position to break away from Trump and Trumpism once and for all. But this is not yet over. Hang on.

From: Heather Cox Richardson from Letters from an American <heathercoxrichardson@substack.com>
Date: Thu, Jan 7, 2021 at 12:55 AM
Subject: January 6, 2021
 

Today the Confederate flag flew in the United States Capitol. This morning, results from the Georgia Senatorial runoff elections showed that Democrats Raphael Warnock and Jon Ossoff had beaten their Republican opponents—both incumbents—by more than the threshold that would require a recount. The Senate is now split 50-50 between Republicans and Democrats, so the position of majority leader goes to a Democrat. Mitch McConnell, who has bent the government to his will since he took over the position of majority leader in 2007, will be replaced. ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌ ‌

	January 6, 2021 Heather Cox Richardson Jan 7 Today the Confederate flag flew in the United States Capitol. This morning, results from the Georgia Senatorial runoff elections showed that Democrats Raphael Warnock and Jon Ossoff had beaten their Republican opponents—both incumbents—by more than the threshold that would require a recount. The Senate is now split 50-50 between Republicans and Democrats, so the position of majority leader goes to a Democrat. Mitch McConnell, who has bent the government to his will since he took over the position of majority leader in 2007, will be replaced. With the Democrats in control of both Congress and the Executive Branch, it is reasonable to expect we will see voting rights legislation, which will doom the current-day Republican Party, depending as it has on voter suppression to stay in power. Trump Republicans and McConnell Republicans had just begun to blame each other for the debacle when Congress began to count the certified electoral votes from the states to establish that Democrat Joe Biden won the 2020 presidential election. The election was not close—Biden won the popular vote by more than 7 million votes and the Electoral College by 306 to 232—but Trump contends that he won the election in a landslide and "fraud" made Biden the winner. Trump has never had a case. His campaign filed and either lost or had dismissed 62 out of 63 lawsuits because it could produce no evidence for any of its wild accusations. Nonetheless, radical lawmakers courted Trump's base by echoing Trump's charges, then tried to argue that the fact voters no longer trusted the vote was reason to contest the certified votes. More than 100 members of the House announced they would object to counting the votes of certain states. About 13 senators, led by Josh Hawley (R-MO) and Ted Cruz (R-TX), agreed to join them. The move would slow down the count as each chamber would have to debate and take a separate vote on whether to accept the state votes, but the objectors never had anywhere near the votes they needed to make their objections stick. So Trump turned to pressuring Vice President Mike Pence, who would preside over the counting, to throw out the Biden votes. On Monday, Trump tweeted that "the Vice President has the power to reject fraudulently chosen electors." This would throw the blame for the loss onto Pence, but the vice president has no constitutional power to do any such thing, and this morning he made that clear in a statement. Trump then tweeted that Pence "didn't have the courage to do what should have been done." It seemed clear that the voting would be heated, but it was also clear that most of the lawmakers opposing the count were posturing to court Trump's base for future elections. Congress would count Biden's win. But Trump had urged his supporters for weeks to descend on Washington, D.C., to stop what he insisted was the stealing of the election. They did so and, this morning, began to congregate near the Capitol, where the counting would take place. As he passed them on the east side of the Capitol, Hawley raised a power fist. In the middle of the day, Trump's lawyer Rudy Giuliani spoke to the crowd, telling them: "Let's have trial by combat." Trump followed, lying that he had won the election and saying "we are going to have to fight much harder." He warned that Pence had better "come through for us, and if he doesn't, that will be a sad day for our country." He warned that Chinese-driven socialists are taking over the country. And he told them to march on Congress to "save our democracy." As rioters took Trump at his word, Congress was counting the votes alphabetically by state. When they got to Arizona, Senator Ted Cruz (R-TX) stood up to echo the rhetoric radicals had been using to discredit the certified votes, saying that public distrust in the election—created out of thin air by Republicans—justified an investigation.  Within an hour, a violent mob stormed the Capitol and Cruz, along with the rest of the lawmakers, was rushed to safety (four quick-thinking staffers brought along the electoral ballots, in their ceremonial boxes). As the rioters broke in, police shot and killed one of them: Ashli Babbitt, an Air Force veteran from San Diego, QAnon believer, and staunch Trump supporter. The insurrectionists broke into the Senate chamber, where one was photographed on the dais of the Senate, shirtless and wearing a bull costume that revealed a Ku Klux Klan tattoo on his abdomen. They roamed the Capitol looking for Pence and other lawmakers they considered enemies. Not finding them, they ransacked offices. One rioter photographed himself sitting at House Speaker Nancy Pelosi's desk with his feet on it. They carried with them the Confederate flag. Capitol police provided little obstruction, apparently eager to avoid confrontations that could be used as propaganda on social media. The intruders seemed a little surprised at their success, taking selfies and wandering around like tourists. One stole a lectern. As the White House, the FBI, the Justice Department, and the Department of Homeland Security all remained silent, President-Elect Joe Biden spoke to cameras urging calm and calling on Trump to tell his supporters to go home. But CNN White House Correspondent Kaitlan Collins later reported that she spoke to White House officials who were "genuinely freaked… out" that Trump was "borderline enthusiastic" about the storming of the Capitol because "it meant the certification was being derailed." At 4:17, Trump issued his own video, reiterating his false claims that he had been cheated of victory. Only then did he conclude with: "Go home, we love you, you're very special." Twitter immediately took the video down. By nighttime Trump's Twitter feed seemed to blame his enemies for the violence the president had incited (although the rhythm of the words did not sound to me like Trump's own usual cadence): "These are the things and events that happen when a sacred landslide election victory is so unceremoniously & viciously stripped away from great patriots who have been badly & unfairly treated for so long. Go home with love & in peace. Remember this day forever!" Twitter took down the tweet and banned the president for at least twelve hours for inciting violence; Facebook and Instagram followed suit. As the afternoon wore on, police found two pipe bombs near the headquarters of the Republican National Committee and the Democratic National Committee in Washington, D.C., as well as a truck full of weapons and ammunition, and mobs gathered at statehouses across the country, including in Kansas, Ohio, Minnesota, California, and Georgia. By 5:00, acting Secretary of Defense Christopher Miller issued a statement saying he had conferred with Chairman of the Joint Chiefs of Staff Mark Milley, Vice President Pence, House Speaker Nancy Pelosi (D-CA), Senate Minority Leader Chuck Schumer (D-NY), and Representative Steny Hoyer (D-MD) and had fully activated the D.C. National Guard. He did not mention the president. By late evening, Washington, D.C., police chief Robert J. Contee III announced that at least 52 people had been arrested and 14 law enforcement officers injured. A total of four people died, including one who died of a heart attack and one who tased themself. White House Counsel Pat Cipollone urged people to stay away from Trump to limit their chances of being prosecuted for treason under the Sedition Act. By midnight, four staffers had resigned, as well as Deputy National Security Adviser Matthew Pottinger, with other, higher level officials also talking about leaving. Even Trump adviser Stephen Miller admitted it was a bad day. Quickly, pro-Trump media began to insist that the attack was a false-flag operation of "Antifa," despite the selfies and videos posted by known right-wing agitators, and the fact that Trump had invited, incited, and praised them. Former Secretary of Defense James Mattis laid the blame for today's attack squarely at the feet of Trump himself: "Today's violent assault on our Capitol, and effort to subjugate American democracy by mob rule, was fomented by Mr. Trump. His use of the Presidency to destroy trust in our election and to poison our respect for fellow citizens has been enabled by pseudo political leaders whose names will live in infamy as profiles in cowardice." The attempted coup drew condemnation from all but the radical Trump supporters in government. Former President George W. Bush issued a statement "on insurrection at the Capitol," saying "it is a sickening and heartbreaking sight." "I am appalled by the reckless behavior of some political leaders since the election," he said, and accused such leaders of enflaming the rioters with lies and false hopes. Senator Mitt Romney (R-UT) was more direct: "What happened here today was an insurrection incited by the President of the United States." Across the country tonight are calls for Trump's removal through the 25th amendment, impeachment, or resignation. The Democrats on the House Judiciary Committee have joined the chorus, writing to Pence urging him to invoke the 25th. Angry at Trump's sabotaging of the Georgia elections in addition to the attack on our democracy, prominent Republicans are rumored to be doing the same. At 8:00, heavily armed guards escorted the lawmakers back to the Capitol, thoroughly scrubbed by janitors, where the senators and representatives resumed their counting of the certified votes. The events of the afternoon had broken some of the Republicans away from their determination to challenge the votes. Fourteen Republican senators had announced they would object to counting the certified votes from Arizona; in the evening count the number dropped to six: Cruz (R-TX), Hawley (R-MO), Cindy Hyde-Smith (R-MS), John Kennedy (R-LA), Roger Marshall (R-KS), and Tommy Tuberville (R-AL). In the House, 121 Republicans, more than half the Republican caucus, voted to throw out Biden's electors from Arizona. As in the Senate, they lost when 303 Representatives voted in favor. Six senators and more than half of the House Republicans backed an attempt to overthrow our government, in favor of a man caught on tape just four days ago trying to strong-arm a state election official into falsifying the election results. Today the Confederate flag flew in the United States Capitol. —-

An Open Letter to Vice President Elect Kamala Harris and President Elect Joe Biden

On an ignominious day for our democracy, the good news that the Democratic Party has regained control of the U.S. Senate going forward was almost completely eclipsed. But, of course, it is of paramount importance.

I will be brief. As an engaged citizen, I want to urge you to recognize that after four years of the most destructive administration in recent history, there is very considerable urgency facing your incoming administration. We need a bold legislative agenda, and as well as a bold regulatory and executive agenda.

The pandemic requires a response that is the near-equivalent of a full-scale war. Not to carp on the matter, but 100 million vaccinations in 100 days is not enough. We need an all-out war on the virus, on all fronts, with the goal victory and the timeline just as soon as humanly possible. A commission to create detailed plans and put them into effect, including invoking the Defense Production Act of 1950, needs to be created.

Bold action on reversing Trump's tax cuts for the very rich, climate change, global alliances and security, environmental protection, jobs and mitigation of the economic impact of the pandemic, and 21stcentury infrastructure will pose tremendous and urgent challenges that call for the most activist and energetic administration at least since 1933. You are capable of this. This is your challenge. The American people are counting on you.

Vice President Harris should come to the Senate and announce that given the 50/50 split, she will sit and preside over the Senate just as the Constitution provides for. The filibuster must be immediately done away with, and the rules of both bodies need to be modified to make efficient and practical legislation possible, without unnecessary and counterproductive obstruction from any faction or party.

As president, Mr. Biden must call for the elimination of the Electoral College by amendment or interstate compact as an interim solution. A recommitment to democracy and service to all the people will go a long way to disabusing followers of the former president of the delusions the deliberate false propaganda which was his stock in trade. When Democrats achieve real results which benefit the great majority of Americans, support for our policies will grow and our ability to further our policy agenda will be well established for years to come.

Thank you.

War on the Virus

Don't want to start carping on Biden already, but the goal of 100 million vaccinations in 100 days isn't adequate or good policy. He should be lobbying Astra Zeneca, J&J, and especially Moderna and Pfizer to prepare themselves for a major Defense Production Act push to ramp up production. Even if it means building whole new plants with government funding... it's worth it. We can use them for aggressive public health projects in the future. Meantime plans to roll out the most aggressive vaccination outreach project in human history should be honed and in place on Day 1. The goal should not be a certain number of vaccinations but ALL OUT WAR on the virus, the goal VICTORY and the timeline ASAP.

our charlie brown christmas tree atop the piano

The Biological Universe

I'm finishing up the new book The Biological Universe, by emeritus evolutionary biologist Wallace Arthur. I made some critical comments on my sometime blog The Gyromantic Informicon [q.v.] about this, but what follows is my specific take on what he calls his Huge Hypothesis, summing up his view of the entire subject. If the general subject of life in the universe doesn't really capture your imagination, you might want to skip the rest of this. 

He proposes that the evidence and reasonable inference supports the following "Huge Hypothesis." I paraphrase a good deal and add in some explanatory comments. These are, to use Thomas Huxley's phrase, "in the indicative," rather than the "potential," even though strictly speaking some of this has to be considered speculative. Most of it is pretty widely accepted in the scientific community today; the additional points I add at the end less so, but I believe they follow logically and are of the same order of certainty; namely, not certain but probable. 

• Life first evolved somewhere in the universe not much later than 10 billion years ago.   [Arthur restricts himself to the observable universe, a space about 93 billion light years across in all directions with us at the center and containing approximately 2 trillion galaxies; the entire universe is much, much larger and, applying the principles of isotropy and homogeneity on large scales, is presumably all much the same]. 
• The oldest instance of the origin of life was overwhelmingly likely to have been on a planet in a galaxy at great distance from the Milky Way, just because there are literally something like a trillion candidate galaxies, each containing hundreds of billions of planets, in the observable universe ("OU" for short). 
• Since that time, there has been a steady increase in the number of locales where life has originated and thrived for a time, and at least a good proportion of them continue to have life at the present epoch, such that some form of life is now relatively common in the universe. 
• QED, the number of planets in the OU with some form of life, mostly limited to microbial life, is many trillions. (Note: every spiral galaxy, and probably many other types of galaxies, as well, have billions to more than a trillion planets, and a typical spiral galaxy like the Milky Way has hundreds of billions of rocky planets situated in the "habitable zone" of their stars where liquid water is possible. The same should be true of most galaxies).
  
  [Arthur includes an additional bullet point, that some systems have more than one inhabited planet; but I regard that as superfluous to the argument].
  
  
• Most or all of the life in the universe is chemically based on carbon compounds. (There are many reasons for including this inference, which I consider to be quite ironclad, but I won't go into it here. My own surmise is that you could correctly say "Essentially all". Fortunately, nucleosynthesis in stars results in the production of a good deal of carbon). 
• Add-in, not included by Arthur:  All, or nearly all, life in the OU has evolved a genetic information recording system that functions analogously to the nucleic acid system that evolved on Earth, although specific details vary considerably.   
  
• Far and away most life in the OU is constructed of cells, although, again, the exact architecture varies considerably. 
• Most life-bearing planets in the OU host only microbial life (single cell or small-aggregates of cells).
• A large number (but proportionally fewer) of the life-bearing planets in the OU also host multicellular life.
• At least some proportion of the biospheres that have evolved multicellular life have evolved "complex" multicellular organisms that conduct photosynthesis to utilize light energy directly (similar to Plants and other photosynthesizer macrobiota on Earth, such as "brown algae"); or that assume roles comparable to those of the Fungi and Animal kingdoms in the Earth biosphere (symbionts and parasites). 
• On at least some of the biospheres that have evolved such "complex" multicellular "animals," some of them have evolved advanced motility, including analogs to skeletal (including exoskeletal) structure, musculature, nervous systems, and the beginnings of intelligence, in the sense of directed control by a "brain." 
• With all intermediate levels occurring in numbers, some portion of the biospheres that have evolved such complex animal life have proceeded to the evolution of human-level intelligence, although exactly how that manifests varies considerably. 

This is where Arthur's Huge Hypothesis ends, but therein lies my principal criticism of his thesis. I think he overestimates the numbers somewhat, especially of the last phase, but I don't disagree with any of the above. I suspect there may be some side roads that lead to unanticipated variants of the types of life we are familiar with, but the main ideas here I believe are sound. But I think they really miss the mark when it comes to a reasonable anticipation of our possible future, which, necessarily, means something analogous to what is already the state of being elsewhere, where human-level intelligence already evolved, in some cases no doubt, a very long time ago indeed. So I would add the following additional levels of development, further along in the sequence. 

• Some portion of human-level intelligent life develops external symbolic manipulation analogous to language, and eventually culture, and then advanced science and technology. This gives organisms the ability to direct their own evolution from this point, at least to an extent. 
• Some portion of the technological species develop artificial biohabitats and are no longer confined to the surfaces of their planets of origin. [I would adventure that we are on the cusp of this development, and that there is no guarantee we will proceed to it; presumably frequently in the past and future, beings at this level do not make this transition successfully or never even try, for whatever reason]. 
• Once at the level of "space-dwelling," most of the technological species proceed to colonize their star systems and later other stars, and to spread the form of life that originated on their planet to vast numbers of other locations in space, including but not limited to planets that did not and might never evolve life on their own, such that over time most of the life in the universe exists elsewhere than the planetary surfaces where it originated. 
• There is virtually no natural limit to the expansion of life under the direction and impetus of intelligence; the future of the OU is for life to encompass a greater and greater proportion of the available locations where sustaining life is possible until some saturation level is reached in the distant future. [Comment: even if this development is relatively rare, it is a threshold; once it occurs, it tends to lead to a permanent change in the course of the development life over a very wide region of space, potentially including multiple galaxies before bumping into others similarly situated, because plausible rates of expansion of such extended biospheres entail small fractions of the age of the planets and galaxies in which they originate. So, ultimately, if this phase occurs at all, it will tend to fill all the available space everywhere].

We are directed by current modes of scientific thought to shun all teleology, but I think it's fair to assess that the "function" of advanced human-level intelligence (and beyond) is to make something like the final three stages of my "even huger hypothesis" possible. I envision an "Age of Life" that is just getting underway in a universe that will eventually be quite literally filled with life. 

I hasten to emphasize the obvious: most of the last two phases mentioned above lie in the future, in most locales. If some regions of the OU have advanced to the level of galaxy-spanning civilizations already, this would likely be apparent in some way were it already common, at least in the relatively nearby regions, say out to 500 million light years. Because, of course, if such developments were to have occurred at that distance, say, 450 million years ago, we would not see any evidence, because the light from that time would not have reached us yet. There could well be the first instances of extremely advanced civilization in parts of space that we just can't see yet. (This assumes, as I think is reasonable, that engineering on a literally galactic scale would change the quality of enough of the light coming from natural luminous sources that the presence of artificial technology would be inferrable). 

Wallace Arthur's «The Biological Universe» and the role of human-level intelligence in the future of life in the universe

This is not really a review of the new book The Biological Universe, by Wallace Arthur; just a few critical points. 

First, Arthur hardly mentions the Fermi conundrum, which, in its fully evolved form, is one of the principal pieces of evidence for the inference that intelligent life, and, probably, what he doesn't like to call "complex" life, are, respectively somewhere between very, very to extremely rare; and at least quite rare. Fermi isn't even circumstantial evidence for the the rarity of complex life per se, except insofar as the presumption is that if life elsewhere reaches the level of say the Cambrian era on Earth (highly complex, long-term stable biosphere with high degree of penetration of all habitats on the planet), it is probably something on the order of at least 1 to 3% likely to evolve to human level intelligence. And if you assume such intelligence is even 1% likely to survive to the level where it is a spacefaring and spacedwelling species, capable of spreading its particular architecture of life far and wide in at least one galaxy, then if you assume that life of this kind is relatively common (as Arthur does), the numbers still don't add up if intelligent life arising even on these life bearing worlds isn't also exceedingly rare. Note that the number of planets with microbial life at any given time is assumed by Arthur, plausibly, to be something like 10 million planets in a galaxy the size of Milky Way  (which is still something like 0.0001% of all planets in the galaxy). 

 

Bottom line, you have to acknowledge that the evidence best supports not a rare life or even extremely rare "complex" life but certainly a very rare human-level intelligence condition. Arthur doesn't really disagree with this but he doesn't address it well at all. The inferential evidence of rare intelligence as an implication that extremely robust and complex life biospheres may be more unlikely than he seems to believe is ignored. 

His main thesis is that the "rare Earth" view is wrong,* and he disputes the very concept of "complex" life, but ultimately his main evidence for this is the same old Earth-centric view of the probability of various "filters" in the evolution of life. Having said that, he did convince me that both eukaryotism (if that's a word)**, or some analogue of it, and photosynthesis are probably closer to inevitable than they are to being filters, in the sense of potential stumbling blocks to the evolution of more "complex" life. As is, apparently, the abiogenic origin of life itself. My best guess is that microbial life is at least as common as Arthur thinks it is, and that the principal reason that very robust biospheres like Earth's remain quite rare, and climax human-level intelligent-life conditions even moreso, is that these or other critical developments for the evolution of macrobiota and subsequently intelligence actually are relatively unlikely, and the universe just isn't quite old enough yet for them to manifest widely. Surely, we can surmise that as vast as the universe is known to be, as here on Earth, complex biospheres, including ones which have given rise to human-level intelligent beings, exist elsewhere in large numbers. But, and this is key from the human perspective, they are apparently very widely scattered. 

My last, and perhaps actually chief, criticism, is as follows. Arthur all but totally ignores the possibility that human-level intelligence itself, when it does evolve, is absolutely critical to the future history of biospheres from which it evolves. He blithely assumes that humans and their descendants will simply become extinct before advancing to a stage where they are spreading terriform*** life elsewhere in the Galaxy, and that we will never exceed the bounds of our own Solar system. My belief, which I think is reasonable inference not just gut feeling, is that if and only if the human species survives the current era, the spread of terriform life far beyond the confines of one star system will be extremely likely. I base this on two assumptions:  if we survive a few centuries, we will likely succeed in building self sustaining space habitats that contain more terriform biomass than the surface of the Earth, eventually. Further, we will likely figure out how to construct some kind of practical interstellar transportation (which could be generation ships or suspended animation, or, just possibly, quite fast in terms of fraction of light speed, drives). I take both of these developments to be generally more or less inevitable if technological societies evolve to the level where they can easily travel in and dwell in space near their home stars. The question then becomes how likely those developments actually are to occur, which translates to how prevalent technological societies are in the universe. And on that point, I hold forth two maxims. 1. Humans are very ingenious; our minds have evolved to the point that there really are no limits on what possible technology we can figure out and build in time; and 2. there is absolutely nothing in this scenario that is impossible. The same maxims should apply with respect to other human-level intelligent beings elsewhere in the universe. 

Arthur mentions virtually nothing discussed in this last paragraph. But they are crucial to his subject, which does purport to discuss the future of life. And if you generalize to other comparably situated intelligent species in a wider universe, the inference that even if we fail others will succeed is hard to avoid. 

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*Reference is to the influential but widely critiqued book, Rare Earth, Why Complex Life is Uncommon in the Universe, by Peter D. Ward and Donald Brownlee (2000, 2003).

** Referring to the evolution of nucleated cells, widely believed to be necessary for the evolution of so-called "macrobiota."

***As far as I know this is an original coinage. The term is meant to refer to life originating on, or descended from life originating on, Earth. 

 

Red Dwarf stars and the Long Range Future of Life in the Universe

Posted this as an answer to a question, but it might conceivably be of interest to some people on its own.

Alien civilizations are very unlikely to evolve on a planet orbiting a red dwarf, for several reasons. First, the habitable zone is small and so close to the star, which by nature is prone to bright flares that can increase the brightness, including in dangerous ionizing wavelengths, by orders of magnitude within short periods of time. These flares are likely to make life very precarious if not impossible on any planets in the zone. Further, planets found this close to such stars will generally be tidally locked, with one face always facing the star. A third problem is that the peak radiation from such stars is in the infrared, so it isn't even clear that photosynthesis could successfully evolve and function in a biosphere on such a planet.

Interestingly, however, there is no real reason that life originating from outside such a system (and these stars constitute about 70% of all stars) could not be transported there artificially, and provided with habitats that would use the light of the star as an energy source. I happen to believe that the Age of Life is just beginning in the universe at large, and the role of intelligent species in assisting the seeding of life in places where it (including its intelligent forms) can exist but is unlikely to spontaneously evolve, will be quite simply incalculably important for the long range future of life in the universe in general.

Since red dwarfs typically have lifetimes in the hundreds of billions to a trillion years, these stars are likely to be the sites of surviving life for far longer than the universe has existed hitherto.

The protein coding problem... one of the great conundra of biology... SOLVED

This is a sure-thing Nobel Prize and may turn out to be the most important scientific discovery in years. Essentially, we now finally know the language that life uses to create proteins, and how to predict the shape, function, and other properties of proteins that any given genetic code text will produce. This is enormously important, and may be the key to solving biological materials shortages, creating medicines from raw materials without having to laboriously process biological resources, and many other as yet unknown developments. This is comparable to the discovery of CRISPR Cas=9 (which google if you don't know what that is)... maybe more important. And one of the most amazing things is that this development was so computation- intensive that it was not actually human intelligence that solved the fundamental problems, but AI, guided by humans. It's a brave new world. 

https://www.vox.com/future-perfect/22045713/ai-artificial-intelligence-deepmind-protein-folding

Sous vide (something other than politics!)

 A little over a year ago I bought a sous vide* bath, sous vide machine, vacuum sealer, and vacuum sealer bag rolls. (The machine is essential, they're about $140-200; the bath, essentially a plastic box with a lid, is not, you can use a stock pot. I recommend the vacuum sealer; the immersion method with ziploc bags is a pain and tends to leak, with bad results). 

At first I only used it to cook perfectly medium rare steaks, to be seared afterwards. (It actually works to sear them before, and is easier). 1 hour at 143°F and perfect color straight through. So I didn't use it that much. But I've discovered cooking  brisket or chuck for 7 or 8 hours at 145° creates perfect meat for pot roast; tender but actually still slightly rare; mix it into already cooked pot roast gravy and vegetables, which take much less time, and it's the best pot roast ever. 

And then there's turkey. We're just two people, so cooking a whole turkey, even the smallest ones you can get, is kind of impractical. So I buy the frozen bone-in breasts, which sometimes cost as little as $8 or $9 and make several meals or a whole bunch of sandwiches. And here's the thing. You can cook it for 3 hours at 165° and then put it in a very hot oven or broiler for 15 min., or you can even just skip that step; remove the skin, and just eat the meat, which is PERFECTLY cooked, moist, tender, and delicious. And the bones make excellent real turkey soup. 

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* Not italicized, it's now a two-word syntactical unit in English, like coup d'etat (without the acute accent, since we don't use diacritics in English). Pronounced "soo veed."

Thanksgiving

 Happy... and Safe... Thanksgiving to Everyone 

Erasmo Acosta on the implications of the Fermi Principle and the future of man

 This is quite interesting, and is along the lines of some things I've written about myself. 

Some thoughts on whether K stars are more likely to be the energy centers for living worlds than G stars, and some implications

Farflung correspondents, this is somewhat rambling and off the top of my head, reflecting my peculiar interests in universal principles of life and civilization. Posted it on Facebook. Got "TLDNR" (too long did not read") from my friend Sue, who often seems to think that's a helpful comment (it is not). Anyway, it occurred to me this might interest you. And if not, of course, you can simply not read it!

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• I've found it fascinating to think about and read what is known about what makes Earth particularly suitable for life, and why there are good reasons to believe it is actually, after all, a highly unusual planet, such that while life of some sort (unicellular, bacterialike) is probably fairly common in the universe, there is pretty good reason to suppose that extremely complex life, in multilayered and globally interconnected complex ecosystems, evolved over literally billions of years of relative climatic stability... what we have here on Earth... may turn out to be really exceedingly rare. The universe is so vast that even very rare things happen many, many times, but that means they are widely scattered and probably unlikely to encounter one another. At least so far. The universe is larger in space than in time... if that doesn't make sense to you, think of it this way. There is a dimension, time, that is 13½ billion units long... back to the Big Bang or its aftermath. That is the operational degree of freedom for change and diversity in the time dimension. But, if some version the Inflation models which are apparently absolutely necessary to make cosmology work is correct, the spatial dimensions go far, far beyond 13 billion light years, because most of the universe is not the observable part, but the part that is too far away for light to ever get here from there. Think of it as having a short dimension in time (if you can get your head around 13 billion years as "short"), and the other three dimensions are almost unimaginably vast. Bottom line: the universe is yet young, yet developing, and while almost all of its "all-time" time as a dynamic and evolving reality is in the future, most of it will remain forever unknown to us because it lies in the untold hugeness of space the light from which can never reach us.

But back to abodes for life, and the conditions for it. Recently, it's been noted in several places where folks who think about this stuff talk about it that there are actually quite a few things about the Solar System and the Earth that are NOT quite ideal for life. Earth is prone to freezing over. It's happened several times, and eventually, if the internal radioactivity settles down too much for volcanism to break through the iceball, it would've been permanent. But even before that, our star is a little too active, and growing too bright (Main Sequence Stars get brighter continuously through their regular, hydrogen-burning lifetimes before entering their red giant phases). In a time less than the time that complex organisms have been present on Earth's surface (about 550-600 million years), the threshold for the beginning of loss of the oceans will be crossed; water vapor will begin dissociating and the hydrogen from water will begin to be lost at the edge of space. It's estimated that in something like 700 million to 1 billion years or so the Earth will have dried up and begun to resemble Mars. Other things, like the gradual diminution of Carbon dioxide from the failure of the carbon cycle (I recommend the book Oxygen, a Four Billion Year History [Canfield] for a description of this), will cause the Ice Ages to return and become permanent. In fact, the current brief epoch of global warming, destructive as it is (and it is), is actually only a temporary reversal of a very long term trend towards the failure of the greenhouse effect, which keeps Earth habitable. Without greenhouse gases, our position vis a vis the Sun would keep the Earth very cold. As the Sun grows warmer, paradoxically, the Earth would grow colder, but then at some point the temperature wouldn't be the main consideration, because global drying is what will make our planet ultimately inhospitable to life.

All this is quite far in the future, and if our descendants survive, they will have plenty of time to migrate elsewhere, but that's not really the point.

The question that I'm intrigued by is, given a world much like Earth, different in details perhaps but basically similar, would a different class of star be preferable? Lead to a longer period of time during which life might not only arise but flourish and the planet remain naturally habitable for longer?

(There are other interesting questions, such as would a slightly more massive planet be better suited (probably, to a point), etc., but this is the question that interests me at the moment).

And the answer seems to be, pretty clearly, yes. The Sun is a G2 star.* Estimated main sequence lifetime somewhere just under 10 billion years. It's just over halfway through that now. Stars as bright as the sun are relatively rare. It is well over the the 90th percentile in mass and brightness. Most stars are little red stars with less than a tenth of the Sun's light output, and, even more problematical, their peak output is well into the infrared and thus perhaps not too suitable for photosynthesis, and they tend to be quite prone to deadly flares (comparable to solar prominences, but to be warm enough for life a world orbiting such a star would have to be close enough to be seriously harmed by such flares). Plus, any planet in the "habitable zone" around such a star will likely be stopped or at least very slow in its turning with respect to the star, so it will have no day and night cycle like Earth, and that leads to all kinds of problems for habitability.

But what about the K type stars? Like Tau Ceti, Epsilon Indi, or 61 Cygni, for some relatively nearby real-world examples. These stars, dimmer than the sun but perfectly capable of illuminating somewhat closer-in Earthlike planets with stable and adequate luminosity. A little more orange, less white, but surely capable of supporting photosynthesis, and, here's what's most important. More stable. Slower rate of increase in brightness (which can be offset by changes in atmosphere or even deliberate advanced engineering). And, the big difference: such stars remain stable and continue shining much longer. The lifetime of a K0 (brighter end of the range) star, like 70 Ophiuchi, is about 20 billion years, while a K7 like 61 Cygni (smaller, dimmer) might live for 50 billion years or longer. And, importantly, they are something like ten times more common than G type stars. All spiral galaxies (and there are untold billions of them in the observable universe, and still more beyond that), have far more K type stars than stars like the Sun, and all those stars are just as likely to have planets. So relatively earthlike planets are substantially more likely to exist in orbit around K type stars than G type, and substantially even less likely to form around the next brighter class, F type, although that is perfectly possible also. The complication that the majority of stars are members of binary or multiple systems is another wrinkle, but at least some of those may be able to support habitable worlds as well. So planets capable of supporting life, whether introduced from elsewhere by intelligent beings like ourselves or naturally evolving on those planets, while not exactly common, almost certainly exist in incalculably large numbers in the wider universe. And even in very large numbers (billions) in our own galaxy. Even if problems causing delays in the development of life are common, we should consider the possibility that the age of "assisted development" (importation of complex life on purpose by intelligent spacefaring beings like our future selves) may be just getting started here and there in the universe. Remember that, overall, the whole universe is about the same age, and life, in all its complexity, takes time and is prone to failures from catastrophes. The past is long but somewhat limited, but the future is unimaginably vast; and some things take a really, really long time to get going.

Anyway, the periods of time that K stars can exist in the main sequence are longer than the universe is old. This leads me to speculate that by far most of the complex living worlds that will ever come into existence have yet to do so; and most of them will arise in systems with dimmer, longer lived stars than the Sun. The Age of Life is just beginning, and the Age of Civilization is mostly in the future.

Fun to think about, and these things may seem remote from our everyday lives, but they are real. We are the Ancients. The Elders. In the prime of the Dawn of Time... from the point of view of most creatures who will live in this part of the universe in all of time. If we don't blow it, we will play a major role in the future not only of this galaxy but beyond it, and will likely seed life from our world on many other worlds, where it will grow and flourish.

[And Donald Trump will be forgotten forever].

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* "Main sequence stars" refers to stars in the main part of their lifetimes, where they are primarily fusing hydrogen for energy and are relatively stable. From brightest (and shortest lived and least common) to dimmest (and longest lived and most common), they are designated O, B, A, F, G, K, M. These designations refer to color, so other stars that have "evolved off the main sequence" also have these letters, but the ordinary so called dwarf stars form a normal continuum. The Sun is G2, meaning brighter end of G. (The scale subdivision runs from 0 (brightest) to 9, dimmest; a G9 might well be classified in another catalog as a K0). About 90-95% of all main sequence stars are dimmer and less massive than the Sun.