Going by these
sources the early "unstable" phase of a red dwarf only lasts about 2 billion years. If a red dwarf was born in the early universe, that time would have passed now. For reference, Proxima Centauri is almost 5 billion years old, not very UV active, and about 0.1% down its lifespan (0.4% down its main sequence). 'course, the planet('s atmosphere) would have to survive this ordeal by radiation for it to be habitable afterwards.
One interesting question on red dwarfs is how likely it is that their Earth-like planets have massive moons or are moons (yes, I know a moon is not a planet, but for the scope of this question one can treat them as the same). Most of the discussion on red dwarf habitability concerns itself with tidal locking & its effects and that presumes that the majority of planets are in fact non-moon lone planets (I'll leave detailed discussions of the 3-body problem to others but I am certain that being an exomoon or having a substantial moon would preclude tidal locking to the star). But is that really so?
Also, since the question of UV radiation and its effects on habitability was raised before, this paper suggests that it wouldn't be a problem.
Lost in Space
It is widely believed that the early Earth was stripped of its water by the young Sun. We only have oceans now because of cometary impacts.
"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"
Heck, to get our moon... Earth had to lose quite a lot.
Like, a massive chunk of crust, a surprising amount of mantle, almost all the existing atmosphere and any ocean (with life) it had started getting to grips with.
Theia didn't seem to leave much of anything behind her when she was practically vaporized (or was almost an identical mix of elements that got so thoroughly incorporated into a fuzzy blob of horrible before it differentiated into a new duo that it's hard to tell which bits are her remains). So, yeah: that's a lot of lighter-element-blasting-away shock waves going on.
Sure, much of the atmosphere kind of came "back" over time, but don't undersell the original amount of material that... didn't come back.
For all we know, we missed a denser atmosphere, even larger ocean potential and something closer to a mega- or super-Earth scenario.
Who knows... we might have getting set back to thoroughly molten in a slightly smaller package to thank for plate tectonics (with the useful magnetosphere) keeping active for as long as they have.
In short: stellar snooker can change the board at any time. And, not just in a negative way for life.
Edited by Euodiachloris on Feb 10th 2020 at 3:33:53 PM
Lost in Space
We were originally talking about how this applies to the Fermi Paradox, and more appropriately how it factors into that component of the Drake Equation describing the chance that any given planet will be suitable for life. At best our current thinking in this regard can be seen as an informed guess, with an extremely high range of possible answers.
The strongest argument in favor of life somewhere else in the universe is the sheer number of planets that exist: quite a few more than there are stars. We have incontrovertible evidence of this now. We know there are plenty of stars like our Sun as well, and so the probability that some of those orbit a suitable star in its habitable zone is also quite high, even discounting other viable solar system configurations.
Between life evolving at all and life becoming spacefaring is a whole range of factors that are pure guesswork. Our best evidence against spacefaring life being common, however, is that we haven't found any yet. Now, we're at the mere infancy of exploring our cosmic neighborhood for individual life-bearing worlds (we cannot currently detect an Earth-like planet around another star), but it is very likely that we would have seen evidence of any alien mega-civilizations in the vicinity by this point.
This detection would come in one of three forms:
- We see mega-structures, such as Dyson Swarms, occluding stars that have no other reasonable explanation. note
- We detect traces of electromagnetic transmissions made by these civilizations. note
- We find direct evidence of our solar system being visited by aliens. note
By direct inference, this means that there is a very large hurdle from planets to planet-colonizing interstellar civilizations, possibly an insurmountable one. Obviously, we cannot know for certain, but the most probable truth at this point is that there is a Great Filter ahead of us.
Edited by Fighteer on Feb 10th 2020 at 12:53:45 PM
"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"
That great filter is almost certainly time. Even if one in every million stars produced a stellar civilization, and every civilization lasted a million years, there probably wouldn't be one nearby right now. Yet this would have produced hundreds of thousands of such civilizations over the life of the galaxy.
I think there’s a global conspiracy to see who can get the most clicks on the worst lies
Well, time and distance.
By the time we might find out about anybody else, they will have been so far away and so long ago as to be gone already. If we can even recognise them.
After all, we might be doing tech very differently.
The galaxy is big. And, when you factor Andomeda and other close clustermates into things, our neighbourhood is bleeding massive. Heck, we don't even know how many galaxies have already merged to form our current one. Or where all the parts went.
So, good luck looking in this ever-changing haystack, the vast majority of which we can only guess the current whereabouts of because we can't actually see it here-now because we're still on there-then.
Edited by Euodiachloris on Feb 10th 2020 at 7:14:13 PM
There is a step between "habitability" and "spacefaring" that is missing - "habitatedness". Remember, the first cell/self-replicating RNA has to arise out of nowhere.
"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." - Richard Feynman
Lost in Space
The counter to that "million years old" argument is the question, "Why would a civilization advanced enough to colonize throughout the galaxy ever have to end at all?" Even if a chunk of that civilization were wiped out, there would be plenty left over. It could spread faster than any disaster or ennui could chase it. If even one such galactic civilization existed at any time in the history of the Milky Way, there should be evidence galore of it.
One possible answer is that we are the first, or among the first: that conditions in the galaxy simply did not allow for intelligent spacefaring life until very recently (in relative terms). This is probably the most optimistic scenario, because it means that the Great Filter may be behind us and we're on our way to immortality as a species if we survive the next 100-200 years.
![[up]](https://static.tvtropes.org/pmwiki/pub/smiles/arrow_up.png "[up]"){kind=icon}
The counter to this is the panspermia hypothesis, which is of course not possible to test right now. Self-evidently, life did evolve at some point, because here we are. The more unlikely this was, the correspondingly higher probability that life evolved in only a few places and then migrated across the galaxy.
According to the Copernican Principle, we are most likely to be among the most typical examples of life of our type, and our type should be the most typical kind of life in the universe as a whole. Further, we should exist during the most typical period in the universe for life to evolve. If galactic civilizations are possible at all given the laws of physics, then this strongly indicates against them being common, but it also means we are likely to exist in the peak of the rise of intelligent life: the highest point in the statistical distribution. If most intelligent species die and only some move on to become interstellar, that means we still have a chance, but it's small.
One Great Filter could be quasars. In the early universe, active galactic nuclei would have sterilized their environments, making the evolution of life impossible. Galactic mergers could reactivate quiescent black holes, similarly scouring away any civilizations that happened to evolve during the lull. That the Milky Way is apparently between mergers means we might have come to exist during an ideal time for life. When Andromeda merges with us in 4-5 billion years, there's a non-trivial chance that it ends all life in the galaxy.
Edited by Fighteer on Feb 10th 2020 at 2:36:26 PM
"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"
Question: why spread far at all?
Seriously, getting anywhere is really effing hard. And, just going the equivalent of to the local cornershop will net a civilisation more resources than it probably can use for millions of years.
In short... No massive spread. Once you have eggs in a few baskets, job done. Heck, the baskets will probably lose contact and evolve to be very different in next-to-no time.
Seriously, the distances we're talking are insane.
Edited by Euodiachloris on Feb 10th 2020 at 7:27:11 PM
Lost in Space
The reason to spread is that your star will eventually die and take you with it. If you haven't spread beyond your solar system or achieved stellar engineering feats beyond the dream of science fiction, you're kaput. Reasonably, we have somewhere between half a billion years and a billion years left here on Earth if we do nothing at all.
If it is at all possible to become an interstellar species given the laws of physics and biochemistry, then a species that achieves it will axiomatically survive longer than a species that does not. This is a basic principle of evolution. Interstellar species should out-compete species that are confined to their home stars, and this must happen during the history of the universe if it is possible at all.
So, the question remains: why haven't we found any? Possibilities: it's very hard to detect them, they are exceedingly rare, or there hasn't been enough time for anyone to accomplish it because the kind of life that could achieve that feat was only possible very recently.
Edited by Fighteer on Feb 10th 2020 at 2:34:52 PM
"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"
When travelling around will literally take you thousands of years (actual and/or relative), you will be meeting new civilisations not your own.
Even though you stem from a shared origin.
Lost in Space
Regardless of whether interstellar travel is possible, any species that becomes technologically advanced enough will need more energy than can be provided by a single planet, and the obvious source is their star. If the galaxy is littered with Type 2 civilizations, we should see evidence in patterns of occlusion in our neighboring stars, created by mega-structures like Dyson Swarms or O'Neill Cylinders.
Edited by Fighteer on Feb 10th 2020 at 2:42:07 PM
"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"
Who says?
For all we know, we're abnormal locusts who can't get by without massive waste.
This is the problem with trying to judge anything from a pool of a handful (us, dolphins and maybe some others).
Lost in Space
There are basic energy requirements to accomplish tasks that are dictated by the laws of physics and engineering. Unless those are different on different planets, we can have a pretty good idea of what would be needed for a civilization to dominate its planet and spread out among other planets in its solar system.
It's not a case of, "Maybe the Flufflebums of Gamma Cygnus can extract 100% more chemical energy from hydrocarbons than we can, or power their rockets with organic vegetation." An alien civilization might decide not to try to escape its planet or develop high technology, but then it is doomed as surely as the dodo when its sun's life ends (or it gets hit with an asteroid, or has a sudden climate change event). This is a basic principle of natural selection that applies just as well on galactic scales as within biospheres.
Again, we can only judge by ourselves, and consider ourselves to be the most typical example of intelligent life in the universe by logical inference. We can't know with any certainty until or unless we discover extraterrestrial life.
Edited by Fighteer on Feb 10th 2020 at 3:06:08 PM
"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"
Lost in Space
NASA has published its FY 2021 budget request. The document from NASA's website is here, with summaries up front. It's long and complicated, but continues support for SLS, Orion, and the Lunar Gateway.
It seems like the bill postpones the Moon landing from 2024 back to its original goal of 2028. Which isn't a complete surprise, the Trump administration was stretching the deadline quite a bit there, but disappointing nonetheless, to see more delays in space exploration.
Life is unfair...
Lost in Space
That's the House authorization bill. As far as I know, the White House and NASA are still pushing for 2024. Let me look... yeah, in the executive summary:
Edited by Fighteer on Feb 10th 2020 at 4:53:06 AM
"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"
Lost in Space
FYI, regarding this week's launches...
- Northrop Grumman: Antares 230+ | Cygnus CRS NG-13 (S.S. Robert Henry Lawrence Jr.): After Sunday's GSE issue, this has been rescheduled to February 13 21:06 UTC (4:06 PM EST). I'm looking forward to another great display of computer graphics as the rocket ascends.
- SpaceX: Falcon 9 Block 5 | Starlink 4: While previously estimated for Feb 14, this is now set for February 15 15:46 UTC (10:46 AM EST). The drone ship that catches the booster had to undergo some maintenance after the last Starlink mission because of the unusually rough landing, but should be ready in time for recovery. I assume SpaceX will try for another double fairing catch as well. They were one for two last time.
Edited by Fighteer on Feb 10th 2020 at 9:11:47 AM
"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"
Lost in Space
Ars Technica, et. al.: NASA confirms Crew Dragon almost ready, mostly paperwork left
Most importantly, we have a tentative launch date: May 7. This is fantastic news. The first manned space flight from U.S. soil since 2011 will ride in a Crew Dragon capsule atop a Falcon 9 rocket.
"We have some subsystems that are in the vehicle that we think might need to be re-engineered with different kinds of metal, we have a tungsten incompatibility in one of the areas that we want to replace with different kinds of tubing," he said. "It's not major, but it's something that has to be done along the way."
NASA and SpaceX are also in final discussions about additional parachute tests to certify that system for flight. It's likely that SpaceX will conduct two additional tests of brand-new parachutes in the coming weeks to satisfy NASA's needs.
Mostly, however, Loverro said NASA needs to complete its analysis of data from Dragon's successful In-Flight Abort test in January and then complete paperwork for the mission.
"Even though it sounds mundane, there is a load of paper that has to be verified, and signed off, and checked to make sure we've got everything closed out," he said. "It is probably one of the longest things in the tent to go ahead and do. It's underappreciated but critically important. You've got to make sure you've done everything you need to do along the way."
The "reengineering" thing confuses me, but I presume they know what they're doing.
Edited by Fighteer on Feb 11th 2020 at 9:40:52 AM
"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"
Lost in Space
From Ars Technica: William Gerstenmaier joins SpaceX, and that’s a really big deal
This is a consequential hire for SpaceX—it is difficult to overstate the influence Gerstenmaier has over human spaceflight both in the United States and abroad. He led NASA's space shuttle, International Space Station, commercial crew, and exploration programs for more than a decade.
He immediately brings credibility to the company's safety culture. Former Space Shuttle Program Manager Wayne Hale, who now chairs the human spaceflight committee of NASA's Advisory Council, told Ars last summer, "Bill was recognized by everybody as being technically well-grounded and very astute. He was known to listen carefully and to make his judgments based on good technical reasons."
NASA Administrator Jim Bridenstine demoted Gerstenmaier in July 2019 because he felt the space agency's exploration programs were not moving forward fast enough. Sources reported at the time that this decision shook some of the agency's partners, who were comfortable with the long-time leader of NASA's human spaceflight program. Some called the engineer in tears after hearing the news.
Worth noting is that Gerstenmaier was instrumental in two critical decisions regarding SpaceX during his time at NASA: first, his decision to offer the Commercial Resupply Services contract to the company in 2008, which saved it from bankruptcy; second, his decision to use two contractors for the Commercial Crew Program instead of sole-sourcing it to Boeing as it had lobbied hard for.
As the article notes, SpaceX has struggled for credibility over its existence despite a near-unbroken string of successes, including numerous firsts for a private company. This addition can only help that image and is a major loss for NASA.
From Twitter, the Cygnus NG-13 ISS resupply mission is now bumped to Friday, February 14 at 20:43 UTC (3:43 PM EST) [1].
Moving away from space flight, I happened upon this article from Science Alert: Powerful Radio Signal From Deep Space Appears to Be Repeating in a 16-Day Cycle
Fast Radio Bursts (FRBs) have fascinated and confounded astronomers for years because they seem to have no obvious explanation. As the name suggests, they are fast (a few milliseconds) bursts of radio frequency energy with the power of entire galaxies. Tracking them to discrete objects or events has proven difficult since they are so unpredictable.
However, new discoveries have identified several FRBs that occur on a predictable cycle and suggested the possibility of many more that repeat, but so faintly that we haven't picked them up yet. We don't think they are pulsars (which cycle much more rapidly and with more predictability) nor are they active galactic nuclei (quasars or the like). It has been suggested that they are tightly orbiting binaries where one partner occludes the other as its beam axis coincides with Earth, but this is as yet unproven.
Studying repeating FRBs may give us powerful insight into their true nature. And no, they aren't aliens, not unless they are powering their civilizations with entire galaxies worth of energy.
Edited by Fighteer on Feb 11th 2020 at 3:01:11 PM
"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"
Lost in Space
Well, this is out of left field. My Twitter feed just coughed up this brand new Snopes article about Firefly Aerospace and its connections to some really shady websites. Firefly is a bidder in NASA's Commercial Lunar Payload Services contract and has been developing its Alpha rocket.
Through a complex web of shell companies, Firefly's owners seem to be tied to a network of fraudulent dating websites under the umbrella of TopOffers.com, all of which work by creating fake profiles and luring men to sign up for "free trials", then hitting them with recurring subscription fees that are impossible to stop. These guys are bidding on NASA contracts, and NASA is supposed to do due diligence on its contractors.
Edited by Fighteer on Feb 12th 2020 at 10:46:45 AM
"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"
Well, contractors working for the US government have their bad reputation for a reason (to whit: inexplicably costly services, often sub-par work, a perception that their selection often involves questionable influence-taking). In fact, I was thinking that much of the resistance against NASA working with Space X and the like was due to concerns that Space X would just become a well of problems like other contractors way too frequently become.
"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." - Richard Feynman
Lost in Space
There is definitely a small but vocal group of SpaceX detractors online who express concerns about the company's commitment to safety. The idea seems to be that it is rushing to innovate at the expense of due diligence and proper standards. This is incredibly ironic given what's been going on with Boeing lately.
The government contracting process is supposed to involve not only safety reviews but also investigations into a bidder's history, funding sources, and so on. The company I work for screens all its vendors to make sure they aren't involved in drugs, money laundering, bribery, etc. Being the shadow owner of a vast network of fraudulent sex sites would seem to be a pretty big red flag.
Edited by Fighteer on Feb 12th 2020 at 10:54:40 AM
"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"
Jupiterian Local
It's not like anyone is giving Boeing a pass just because they're Boeing. Their shortcomings have been revealed by the same sort of testing process that Space X is going through (and has so far passed with flying colors). The skepticism arises from the fact that the testing process was designed to deal with companies that operate like Boeing, not companies that operate like Space X, so there's a not-unreasonable fear that it might miss something Space X is doing wrong that it would have caught from Boeing.
Really from Jupiter, but not an alien.
Red dwarf stars become more stable over their lifetimes, as well as brighter, but they can live for a trillion years or more. Even if a red dwarf formed at the earliest possible time for a star in our universe, it would have lived barely a hundredth of its potential.
"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"