[HN Gopher] Hurried Thoughts: You're Wrong About Tidal-Locking
       ___________________________________________________________________
        
       Hurried Thoughts: You're Wrong About Tidal-Locking
        
       Author : sohkamyung
       Score  : 185 points
       Date   : 2024-03-07 14:08 UTC (8 hours ago)
        
 (HTM) web link (worldbuildingpasta.blogspot.com)
 (TXT) w3m dump (worldbuildingpasta.blogspot.com)
        
       | mistercow wrote:
       | This seems to offer an interesting (partial) candidate for the
       | Great Filter. What if there are tons of advanced civilizations on
       | tidally locked planets orbiting red dwarfs, who have never
       | reached for the stars, because they simply can't see them?
       | 
       | Or rather, they can see them only once they've developed the
       | technology to explore a side of the planet which they're
       | extremely poorly adapted for. Imagine if we had only been able to
       | even begin to study astronomy through polar expeditions, for
       | example.
        
         | HPsquared wrote:
         | Not having celestial navigation would also make such
         | exploration more difficult.
        
           | mistercow wrote:
           | Yeah, although given that ancient humans figured that out,
           | maybe it wouldn't take an advanced civilization very long.
           | That's probably the biggest flaw with the idea. Like, imagine
           | a civilization at our stage, minus the stuff we learned by
           | having a night sky (no universal gravitation; computers and
           | radio, but no GPS; quantum physics but no general relativity,
           | and so on). Now they manage to voyage into the cold, dark
           | night. How quickly can they catch up? Decades maybe, but
           | probably not centuries.
           | 
           | I think the other question is cultural. How much do they
           | _care_ about space, when even the basic concept is new and
           | alien, and studying it is very expensive?
        
             | fnordpiglet wrote:
             | I'd note that navigation was most important on oceans while
             | terrestrial navigation relied on landmarks and maps.
             | 
             | I wonder though how much exploration helped lead to an
             | advanced civilization. The exchange of ideas with different
             | cultures was crucial as was the necessity to develop the
             | technologies for exploration beyond navigation alone. It
             | wasn't until we broadly navigated the planet that we
             | advanced so rapidly after tens of thousands of years of
             | relatively isolated stagnation.
        
               | TheOtherHobbes wrote:
               | I have a theory that Western culture developed relatively
               | quickly because the geography is basically easily-
               | farmable land around an inland sea with plenty of islands
               | which is easy to navigate and explore.
               | 
               | The Egyptians and the Phoenicians lacked the easily
               | farmable land. Greece was fertile but a little arid,
               | Northern Europe was harsher and riskier, but Rome was in
               | a perfect sweet spot.
               | 
               | On the other side of the world China had the farmland but
               | not the inland sea, so there was less motivation for sea-
               | borne trade and exploration.
               | 
               | So it all started with a tradition that required basic
               | materials science, knowledge of the weather, currents,
               | and seasons, navigation by the sky, and the politics of
               | war and trade across large distances.
               | 
               | And it didn't stop until we had explored the entire
               | planet and taken the first steps into space.
               | 
               | In between we had to learn about time, navigation, and
               | planetary weather patterns, how to build and power better
               | ships, and more complex politics.
               | 
               | It seems like a very natural progression.
        
               | fnordpiglet wrote:
               | A few notes -
               | 
               | Western culture didn't develop very quickly - the
               | geography had humans for tens of thousands of years
               | before culture developed quickly. Other parts of the
               | world actually developed relatively advanced
               | civilizations long before Europe.
               | 
               | I think once it began to develop it developed quickly
               | partially due to the geography, but it was also through
               | trade with the Middle East and Asia, which were the
               | sources of a lot of the technology bootstrap priming
               | Europe to develop rapidly. It's indisputable that once
               | the ball really began rolling Europe brought us to the
               | modern age rapidly. But I'm dubious of the geography
               | argument personally since it was so late in developing
               | relative to other societies, including those in the
               | americas.
               | 
               | China actually was an advanced maritime society, with
               | expeditions across most of the world including to the
               | Americas. In fact in the 1400s China was the world's most
               | powerful navy.
               | 
               | https://en.m.wikipedia.org/wiki/Naval_history_of_China
        
               | Bene592 wrote:
               | China had the sea between China and Japan, and they had
               | some nice oceangoing ships1.
               | 
               | [1] https://en.wikipedia.org/wiki/Junk_(ship)
        
             | marcosdumay wrote:
             | > the stuff we learned by having a night sky
             | 
             | You are forgetting stuff like platonic modeling of the real
             | world, testing hypothesis on the basis of their predictive
             | values, and integrating the smart people as a community
             | where they exchange ideas.
             | 
             | We learned all of those by observing the sky.
             | 
             | Of course, there are probably other ways to learn it. But
             | it's not clear at all how viable they are or how long they
             | would take.
        
             | kjkjadksj wrote:
             | We really didn't even care about space, until we decided
             | spaceflight might lead to easier control of the strings of
             | power through use of icbms or even manned space stations.
             | Then it became an appreciable fraction of our GDP
             | overnight, from no polling of voters only under the
             | pressure of our unelected military authority.
        
               | mistercow wrote:
               | For space exploration sure, but astronomy was a pretty
               | big deal for centuries before space flight was a remote
               | possibility.
               | 
               | But I think the fact that the stars are staring you in
               | the face on a regular basis when you look up has to have
               | been a big influence there. For our hypothetical tidally
               | locked culture, the stars would be, to most people, more
               | akin to the cosmic microwave background. They'd be
               | something scientists could take pictures of and form
               | theories about, but totally removed from everyday
               | experience.
        
           | neaden wrote:
           | On the other hand, having the sun as a fixed point seems like
           | it could make it much easier, presumably navigation would be
           | based around that.
        
           | wolfram74 wrote:
           | If the planet had a decent magnetic field, it might actually
           | be quite easy to navigate. A sextant would get you "solar
           | latitude" as it were (the angle of the sun relative to the
           | horizon defines a circle), and coupled with magnetic
           | orientation I think that would narrow it down to one of four
           | points on the day side of the planet (where the field lines
           | have a given angle with the radius of the previously defined
           | circle). Given even crude object permanence I think that
           | should fix your position pretty well.
        
             | amluto wrote:
             | On the night side, you could get a decent idea of your
             | absolute position by observing the stars, just like how you
             | can do this on Earth if you have a good clock. On a tidally
             | locked planet, your clock doesn't need to be very good.
             | 
             | I imagine that a similar if somewhat more complex trick
             | works on the day side if there's a visible moon.
        
               | jonathanlydall wrote:
               | The stars would still rotate around the planet, but the
               | rotation would be that of the planet rotating around its
               | star.
               | 
               | So one would need timekeeping to track where you are in
               | that cycle.
        
               | amluto wrote:
               | Indeed, but process is quite a bit slower, so you could
               | likely get away with a worse clock.
        
               | IntrepidWorm wrote:
               | Since the cycle of stellar observation repeats each solar
               | year, the observation would itself be a method of time
               | keeping. One would need only to track the azimuth of a
               | series of regularly positioned star constellations to
               | determine time, and from there one could then ascertain
               | location.
        
             | saagarjha wrote:
             | Do tidally locked planets typically have a magnetic field?
        
           | PaulHoule wrote:
           | If the sun is always in the same place it is easy to figure
           | out how far you are away from the center. If the planet is so
           | lucky to have a dipolar magnetic field you can get a 2-d
           | position, and it would be easier than being on Earth because
           | you don't need an accurate clock the way you do on Earth:
           | 
           | https://www.destination-innovation.com/john-harrison-the-
           | mas...
           | 
           | ... assuming of course you can see the sun which might be
           | trouble when you get sunwards (too many clouds)
        
             | Bene592 wrote:
             | A planet that Spins only once in one of its years probably
             | isn't dipolar
        
               | PaulHoule wrote:
               | Mercury has a low rotation rate but it does have a weak
               | magnetic field: see
               | https://en.wikipedia.org/wiki/Mercury%27s_magnetic_field
               | 
               | I'm not so sure how easy it is to make a compass that
               | works on a weaker field.
        
           | tzs wrote:
           | A tidal locked planet is still rotating, just a lot slower
           | than more "normal" planets, so maybe you could use some of
           | the effects of the rotation to help figure out position?
           | 
           | For example set up a Foucault pendulum and observe it long
           | enough to determine the angular speed of its precession. From
           | that you can determine your latitude. There will be only two
           | points on the surface of your planet that have that latitude
           | and have your sun in the right place.
        
         | Galaxeblaffer wrote:
         | Very interesting idea ! I do wonder though if sufficiently
         | complex life would ever evolve in an almost completely stable
         | climate.
        
           | johngossman wrote:
           | The tropics have more life and a more stable climate than the
           | temperate regions. They also are warmer, so that's not an
           | argument that a stable climate is more amenable to life, but
           | at least a hint it isn't an overriding factor. I also realize
           | that may not say much about the origin of complex life. Just
           | trying to think of examples.
        
             | Ekaros wrote:
             | Not to forget deep sea is also very stable in temperature.
             | Being function of denseness of water.
        
         | johngossman wrote:
         | An even more extreme version of this is life in the seas under
         | an ice world like Europa.
        
         | bombcar wrote:
         | If we were tidally locked, and were about where we are now or a
         | few centuries ago, there'd be tons of people trying to explore
         | the "dark side of Earth" and they'd see the stars.
        
           | rini17 wrote:
           | They likely don't have night vision, so they would need to
           | use instruments. They can only discover stars (perhaps except
           | few brightest ones) after invention of photography.
        
             | CuriouslyC wrote:
             | I think it's more likely that the interesting life would
             | evolve from organisms that exist on the fringe and can
             | survive and migrate to either side.
        
             | bluGill wrote:
             | Do they have fire? Clouds mean they already can adjust to
             | different light levels - at least some. A fire lit torch is
             | obvious if you have fire.
        
             | andrewflnr wrote:
             | "Night vision" is not a special binary adaptation. It's not
             | as if humans have exemplary might vision either, and we see
             | LOTS of stars in a dark sky. Plus there are lots of diurnal
             | reasons to not be helpless in low light, like tree cover
             | and caves.
        
             | bombcar wrote:
             | They'd likely have discovered caves or roofs at some point
             | - and have some ability to see in dimmer light.
        
         | otabdeveloper4 wrote:
         | Hot take: the Great Filter is the fact that we're actually
         | alone as an intelligent species in the universe.
         | 
         | Occam's Razor and all that.
        
           | mistercow wrote:
           | That's not an explanation. It's a restatement of what the
           | great filter is trying to explain.
        
             | otabdeveloper4 wrote:
             | Occam's Razor says that we don't see any aliens because
             | none actually ever exist.
             | 
             | Anything else is, alas, wishful thinking.
        
               | root_axis wrote:
               | Occam's Razor would suggest we just don't have the
               | technology to detect them, you'd need extra reasoning to
               | explain why earth is unique among thousands of trillions
               | of planets.
        
               | mistercow wrote:
               | Again, that's not an explanation. An explanation would
               | explain _why_ aliens don't exist despite apparently ample
               | opportunities for them to.
        
               | sfink wrote:
               | I don't think Occam's Razor is that helpful in explaining
               | why I can't find my glasses in a pitch black room. A
               | better explanation is that it's dark. There may well be
               | other good reasons, but Occam's Razor says to stick with
               | it being dark.
               | 
               | Other stars are a long ways away, and intelligence-
               | generated signals mostly dissipate into the cube of that
               | distance. Also, the vast majority of stars are far enough
               | away that intelligent life would have had to evolve a lot
               | sooner in order for the light to have already reached us.
               | Occam's Razor is going to look at those before working
               | out the more complicated questions of how common life and
               | intelligence actually are.
        
           | solardev wrote:
           | Maybe the _actually_ intelligent species created this
           | universe as a zoo to keep us safely tucked away so we don 't
           | eat their kids. Then they had some massive layoffs and
           | couldn't afford faster than light vacations for a while :(
        
           | etskinner wrote:
           | That doesn't really follow Occam's Razor. That would require
           | assuming that we're special in being the only planet/solar
           | system/galaxy where life happened, even though the conditions
           | are right in lots of places
        
           | Jerrrry wrote:
           | Occam would presume, as most do, that we are the first
           | sufficiently advanced, detectable, species to leave the
           | gravitational well we were born in, and the first in the
           | observable universe, so far.
           | 
           | There is more to the universe than what we can observe, our
           | light cone is a fraction of the expected higher bound,
           | assuming a finite universe.
           | 
           | We are also one of the first generation of planets with heavy
           | elements - decreasing the odds of a species originating
           | before us.
           | 
           | But the universe will be around for a long, long time;
           | 
           | Far, far longer than it has so far. We may be the first, but
           | to assume a filter at this point is an anthropomorphic bias
           | so ingrained it's nearly impossible to cognitively self-
           | reflect on.
        
           | throwanem wrote:
           | 200 billion galaxies in the observable universe, 100 billion
           | stars just in this galaxy, and this one star among those
           | quadrillions being the only one with intelligent life - this
           | by you is the _simplest_ explanation?
        
             | bluGill wrote:
             | Are we the only intelligent life or not. Both Yes and No
             | answers would be astonishing, though for different reasons.
             | 
             | The question however is unknowable: the speed of light
             | compared to the size of the universe is just too slow. We
             | have every reason to believe most intelligent species will
             | rise, develop, and die off (as their star dies!) and we
             | never find out about them - either the signals never reach
             | us before our star dies, or they have already passed us by.
        
             | WithinReason wrote:
             | It would just mean that life is improbable, which is
             | perfectly plausible.
        
               | throwanem wrote:
               | Plausible, sure, but such a vast improbability itself
               | requires what would have to be quite a complex
               | explanation.
        
               | WithinReason wrote:
               | Why? It could be simply statistically unlikely, nothing
               | complex about it.
               | 
               | https://en.wikipedia.org/wiki/Anthropic_principle
        
         | lynx23 wrote:
         | That sounds like a Greg Egan book yet to be written :-) I
         | discovered that it is real fun to think about these things when
         | I read Incandescence. BTW, I am taking recommendations for
         | books similar to that one, it appears I love that subgenre.
        
         | kjkjadksj wrote:
         | We've had to go up to snowy, oxygen depleted mountaintops to
         | study our own astronomy too. For a while even such study was
         | deemed heretical by the church. There are many potential
         | filters to science. Many still in place with our own species
         | today, even.
        
         | klyrs wrote:
         | Life is attracted to gradients; I would expect the most
         | interesting behavior at the twilit ring.
        
           | sfink wrote:
           | But the article's main point is that the
           | intermediates/gradients in heat and moisture are not
           | necessarily where you expect them to be. If you have a point
           | heat source on one side of an enclosed volume--a big box, say
           | --then in a vacuum the most "interesting" area is halfway
           | between that point and the far wall. But if there's a gas or
           | liquid in the box, convection will produce a flow where the
           | interesting regions are scattered around and that midway
           | point is probably one of the less interesting spots.
           | 
           | Life is also attracted to energy. Even if it started in the
           | twilit ring, it would compete to fill the most insolated
           | areas, and would be lushest there.
           | 
           | I think it's more like life is attracted to the volume of
           | flow. A gradient is what drives the flow, but the flow has
           | velocity and so sums up the gradient over a history of
           | motion.
        
       | taeric wrote:
       | Very fun article. I don't feel that I was "wrong" going in, as I
       | had no real concept of most of this. I was definitely ignorant of
       | a lot of scenarios, though.
       | 
       | In particular, I knew the moon was tidally locked to the earth;
       | but that was about as far as my thinking on that went. I'd
       | somewhat assume that the moon is "swelled" towards the earth, but
       | maybe not because then the sun would break the lock? The article
       | covers that the general variables involved with moon orbits
       | largely precludes this, I think.
       | 
       | Would be a lot of fun to have a VR experience that lets you see
       | some of this from the different perspectives.
        
         | solardev wrote:
         | Don't know about VR, but Space Engine on Steam seems to have
         | tidally locked planets...
         | 
         | https://forum.spaceengine.org/viewtopic.php?t=206
        
           | taeric wrote:
           | I doubted what I'm asking for exists, yet. Basically a "hands
           | on" experience in the latest simulations we know. Always fun
           | to see others are already there working on a lot of this.
        
       | jrd79 wrote:
       | Is it possible to collect actual observations to confirm or deny
       | the results of this modeling? A key part of any well formed
       | scientific hypothesis is that it can be validated or disproved by
       | real world experimentation or observation (falsifiable). Where
       | will that data come from in this case? Computer models are an
       | important part of science, but if they can't be validated against
       | data, what's the point?
        
         | johngossman wrote:
         | One of the references has a section on Implications for
         | Observations of exoplanets.
         | 
         | https://iopscience.iop.org/article/10.3847/1538-4357/aa9f1f/...
        
         | s1artibartfast wrote:
         | It seems quite falsifiable. We Just need to visit or image
         | several hundred tidally locked planets in the habitable zone.
         | 
         | Also, theory and models still have value in the absence of
         | experimental data. They can inform your decisions on what
         | experiments to run! They can also inform your decision on how
         | to behave in the absence of data and validated models.
        
       | johngossman wrote:
       | Count me as wrong. One of the things I learned about weather is
       | that the winter cold is largely an effect of surface heat
       | radiating into the sky at night. The paper indicates that
       | atmospheric circulation is enough to compensate for that and keep
       | the dark side warm. Not a climatologist: but how do you explain
       | the Earth's poles then? One of the charts shows the dayside
       | average at 300K and night at 250K. That second number is warmer
       | than our Arctic in winter.
        
         | s1artibartfast wrote:
         | >One of the things I learned about weather is that the winter
         | cold is largely an effect of surface heat radiating into the
         | sky at night.
         | 
         | I wouldnt say "largely". My understanding is that the hours of
         | daylight is more significant than hours of night, though
         | obviously related. A cursory review seems to indicate that
         | daytime flux at the surface is on the order of +250 W/m^2,
         | whereas nighttime flux is much lower ~ -50 W/m^2
        
           | o11c wrote:
           | Hm, but daytime flux is highly angle-dependent, whereas
           | nighttime flux is angle-independent ...
        
             | s1artibartfast wrote:
             | Another way to think about it is that radiative surface
             | cooling isnt just at night. a black body radiates
             | continuously 24 hours a day.
             | 
             | The only thing that changes throughout the day is the
             | amount if inbound solar flux.
        
         | Jerrrry wrote:
         | The poles receive sunlight at a near 90 degree angle, ignoring
         | the axial tilt.
         | 
         | Direct sunlight vs. spread over an area.
        
         | throwuwu wrote:
         | On a tidally locked planet the polar region is effectively the
         | terminator line. There is also a greatly reduced Coriolis
         | effect due to the very slow rotation. The insolation of the day
         | side is a lot higher as mentioned in the article and is
         | continuous rather than intermittent. All of that would lead to
         | increased convection. Imagine the difference between a kettle
         | being heated on a burner vs a kettle being heated by a
         | blowtorch that rotates around it. The behaviour of the fluid in
         | each will be quite different. Not a perfect model by any
         | stretch of the imagination but maybe more intuitive.
        
       | ak217 wrote:
       | This is a fascinating analysis, but it doesn't mention the
       | magnetosphere. I'm an amateur, but my understanding is that tidal
       | locking means effectively no rotation with respect to the aspect
       | of the solar wind. No rotation means no coriolis. No coriolis
       | means no dynamo. No dynamo means no magnetic field to protect the
       | planet. No magnetic field means the solar wind will strip the
       | atmosphere, no?
        
         | hlava wrote:
         | Well, Venus doesn't generate its magnetic field via geodynamo.
         | Instead, it has some sort of weak magnetosphere induced by the
         | interaction of the solar wind with the planet's ionosphere.
         | Also even without this magnetic field, I guess the volatile
         | processes on the surface are enough to keep the atmosphere
         | going.
        
         | dakr wrote:
         | I was also wondering about the stellar wind stripping away the
         | atmosphere. Planets close enough to their stars to be tidally
         | locked will experience more stellar wind than those farther
         | away and dwarf stars have more flare events than stars like our
         | sun does, exacerbating the problem (plus flares can release a
         | lot of high energy photons, which can break apart structures
         | like DNA).
        
         | sfink wrote:
         | Yeah, that seems to be the elephant in the room. It's great
         | that planets tidally locked to a red dwarf can block the heat
         | with clouds, and mix the heat around with their atmosphere and
         | ocean. But if being stuck up against a star means their
         | atmosphere will be stripped off, then there will be neither
         | clouds nor wind to do any good.
         | 
         | Then again: Mercury has a dynamo-generated magnetic field, yet
         | has the thinnest atmosphere of all of our planets[1]. Venus
         | does not have a dynamo-generated magnetic field[2], yet has an
         | extremely thick atmosphere. So it's not totally cut and dried.
         | 
         | And there's of course the possibility of life in subsurface
         | water. If the atmosphere were stripped, must the planet end up
         | dry? Subsurface oceans can still mix the heat around. It could
         | be underneath crust or ice (though the low atmospheric pressure
         | would probably eliminate any ice near the top, so if it's ice
         | it's probably underneath a crusty layer).
         | 
         | Could tidal forces themselves drag enough magma around to
         | generate a magnetic field good enough for shielding? The
         | Earth's magnetic field from ocean tides is 20000 times weaker
         | than the main one[3], but that's based on ions dissolved in
         | water pulled by a relatively weak tidal force. What's a few
         | orders of magnitude between friends?
         | 
         | 1. https://www.sciencedirect.com/topics/earth-and-planetary-
         | sci...
         | 
         | 2. Venus has a small induced magnetosphere from solar wind
         | hitting the ionosphere, but that's probably something that
         | would lead to more loss, not less?
         | 
         | 3. https://www.sciencealert.com/esa-swarm-satellite-map-
         | ocean-t...
        
       | adrynile wrote:
       | i thought this was about the new DJ locks Tidal (the lame music
       | service) put up. this is much more interesting :)
        
         | jonathanlydall wrote:
         | I wonder if it's like Spotify's new AI DJ.
         | 
         | Which I listened to for only 10s of minutes before it played a
         | type of song completely unlike anything I'd ever listened to
         | and would never listen to, at which point I was like "nope!"
         | and I have no intent of trying it again.
         | 
         | I also don't care for DJ chatter, so didn't like that, but if
         | it helped me find more tracks similar to what I was listening
         | to, I could live with it.
         | 
         | What I want from my music streaming is a little bit of variety
         | on what I already listen to. Essentially a huge shuffle list
         | with occasional new tracks I can up or downvote, further
         | training it on what kind of music I like.
        
         | risenshinetech wrote:
         | No you didn't. You just saw the worlds tidal and locking and
         | figured you would make a cute comment about something clearly
         | unrelated.
        
       | FranOntanaya wrote:
       | I do remember Earth exceptionalism being pervasive, from the
       | first satellite views of Mars up till maybe Galileo's pictures of
       | Europa.
       | 
       | Even today still get that feeling when it comes to the topic of
       | liquid water, where people will point at the lack of meaningful
       | atmospheres and declare places like Mars or any other body
       | holding ices as too different to not be dry, when you just need
       | the right ground temperature gradient and some trapped ice.
        
         | bluGill wrote:
         | We don't really know what life requires. We know that earth has
         | life. We have insufficient evidence for anyplace else (there is
         | some evidence of life in our solar system but it could have
         | been life that escaped our orbit by chance, or just
         | contaminated sensors). All we have for sure is life exists on
         | earth, so we know life exists on earth.
         | 
         | Wikipedia has a list of other chemistries that could maybe
         | support life, but we don't know if they do in the universe or
         | not. We know that the basics of life on earth (water, carbon)
         | are very common in the universe, and so there is no reason to
         | think that life as we know it should be rare - but we also have
         | no evidence of life elsewhere (mostly because we don't even
         | have the ability to see evidence if it exists - the universe is
         | large and we can't detect the important things even a few light
         | years away)
        
       | verisimi wrote:
       | > I just figured it'd be nice to have a single relatively short
       | place to address the most common myths about tidal-locked
       | planets, and particularly their climate, for easy reference.
       | 
       | Well that's nice and all, but this sort of explanation is hard to
       | take! How can one verify that whatever-it-is about tidally locked
       | planets, is not also a myth?
       | 
       | Sure, these might be better set of guesses and assumptions, but
       | it still cannot debunk myths.
       | 
       | To see what I mean, I can debunk the idea that the gods live on
       | top of Mount Olympus by climbing the mountain and checking. I
       | can't check any of these potentially valid deductions. In fact,
       | he could make the exact opposite points, and I would have no
       | idea. None of us would.
        
         | s1artibartfast wrote:
         | If someone trusted the old speculative models, they can choose
         | to update to the new speculative models.
         | 
         | If someone doesn't want to update their myth/model, who cares?
         | Consensus and alignment don't matter.
         | 
         | Even if you're wrong and you know it, there's no reason that
         | should stop you from writing fiction the way you want.
        
       | at_a_remove wrote:
       | I'm interested in that six image chart. The insolation seems
       | _high_.
        
       | causal wrote:
       | What an incredible blog. The pricing list on the left is
       | particularly great - "want me to design a world for you? Here's a
       | feature menu"
        
       | causal wrote:
       | Fun to imagine how a tidally-locked civilization would grow up
       | seeing a lot more symmetry in their environment than we do, and
       | how their myths might spring up as a result.
       | 
       | Also funny to imagine their scientists dismissing Earth as
       | possibly habitable- "spinning around and around like that would
       | result in impossibly complex weather systems - no way that's
       | stable enough to sustain life!"
        
         | rob74 wrote:
         | What would be fascinating is imagining how the permanent
         | daytime would influence their perception of time. The day is
         | after all the fundamental unit of all human timekeeping, along
         | with the seasons, and a tidally locked planet would have none
         | of those. Maybe, if they are lucky, a moon big enough to be
         | visible during daytime?
        
           | causal wrote:
           | Yeah! Also the mystery that the night-side of the planet
           | would hold. If permanent cloud-cover for the day side holds
           | true, then star-filled skies might just be a legend brought
           | back by those who braved the darkness and lived to tell about
           | it.
        
             | mangamadaiyan wrote:
             | Interesting parallels to Asimov's "Nightfall" there!
        
           | QuadmasterXLII wrote:
           | "Can a tidally locked planet have a moon" is a fascinating
           | newtonian physics problem- I am thoroughly nerd sniped
        
           | Terr_ wrote:
           | In some cases they might also observe the "fixed" stars.
           | (Depends on their habitat zone, atmospheric composition and
           | weather, what kind of eyes they evolve, etc.)
           | 
           | If so, they could easily measure "one year", and possibly
           | subdivide it further, based on either consistent angle-
           | measurements or roughly-similar chunks based on designating
           | constellations and when they vanish or reappear.
        
       | bilsbie wrote:
       | That's great news. How cool it would be to visit such a planet.
        
       | egberts1 wrote:
       | Aw man, "tidality" is yet another variable that needs to be added
       | on to the Drake Equation.
       | 
       | (The Drake equation is a probabilistic argument used to estimate
       | the number of active, communicative extraterrestrial
       | civilizations in the Milky Way Galaxy.)
       | 
       | https://en.wikipedia.org/wiki/Drake_equation
        
         | syncsynchalt wrote:
         | Covered in either n_e, f_i, or f_c I would think, depending on
         | which of the three you're concerned that tides[1] or being
         | tidally-locked would affect.
         | 
         | [1] I mention tides because there are hypotheses that the
         | presence of luna greatly contributed to abiogenesis and/or the
         | mechanism by which life first left the oceans.
        
       | mlhpdx wrote:
       | I like this refreshed model of the "eyeball" planet -- perfect,
       | endless beam reach sailing.
        
       | capitainenemo wrote:
       | BTW, if the page author happens to be reading this. (loved the
       | article BTW)
       | 
       | Your header image Screenshot_15.png is 21/2 megs in size which is
       | pretty brutal on slower connections or for those with data costs.
       | Plus it causes it to load a lot less snappily even on a decent
       | connection. It is served in a fixed width 827px container yet is
       | 1902px in size. Given the content (a simulated planet with fuzzy
       | content) extra detail for HD isn't super useful and png will not
       | compress well. Allowing for a little extra width for later
       | retheming and then recompressing as jpeg...                   $
       | convert Screenshot_15.png -scale 1240x Screenshot_15_1240.png
       | $ ~/hg/mozjpeg/cjpeg Screenshot_15_1240.png >
       | Screenshot_15_1240.jpeg         $ ls -l Screenshot_15_1240.jpeg
       | -rw-r--r-- 1 nemo nemo 65870 Mar  7 13:55 Screenshot_15_1240.jpeg
       | 
       | 2.6% the size of the original.
        
         | kakkun wrote:
         | Also, there are some font size inconsistencies in the main body
         | that should be looked into.
        
         | wiredfool wrote:
         | My bank has a similarly sized png as the texture background of
         | their pages, and sometimes it visibly, slowly, loads fresh on
         | each page you go through.
        
         | EvanAnderson wrote:
         | You're doing God's work. Thank you for caring.
        
         | tux1968 wrote:
         | You might want to check out a large-image blocker for your
         | browser, like this one for Firefox:
         | 
         | https://addons.mozilla.org/en-CA/firefox/addon/large-image-b...
        
       | Razengan wrote:
       | When I first played Monkey Island, the thing I oddly loved a lot
       | about its world-setting was how some islands were perpetually in
       | night and others in day.
       | 
       | Of course that was a technical limitation and not an intended
       | feature of the setting, but I always wondered how such a world
       | might be possible.
       | 
       | Now I have the answer. :)
        
       | 867-5309 wrote:
       | imagine what tidal locking might do to the subterranean layers of
       | a planet, compared to Earth's isotropic rotisserie
        
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       (page generated 2024-03-07 23:00 UTC)