Hurried Thoughts: You're Wrong About Tidal-Locking(worldbuildingpasta.blogspot.com)
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Hurried Thoughts: You're Wrong About Tidal-Locking
https://worldbuildingpasta.blogspot.com/2024/03/hurried-thoughts-youre-wrong-about.html
128 comments
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?
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.
Interesting parallels to Asimov's "Nightfall" there!
"Can a tidally locked planet have a moon" is a fascinating newtonian physics problem- I am thoroughly nerd sniped
Isn't that just Lagrange points?
I thought that’s what happens on Pluto
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.
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.
Especially since their year would be much much shorter than ours
> much much shorter
My napkin math yields "as short as 1/3 Earth year", however I'm not sure I'd call that much^2 shorter, given some of the variety out there.
I'm eyeballing the graph in the linked blogpost, which has a dashed line for 4.5by solar-system age versus the optimistic "habitable" ranges. In particular, minimizing the distance gives (distance=0.4, star_mass=0.4) and trading off a bit for a more massive star (distance=0.5, star_mass=1.0).
The period of a circular orbit is proportional to (distance^3 / star_mass)^0.5 [0], so when I plug those pairs in I get orbital periods of ~0.4 to ~0.35 Earth years, respectively.
[0] https://en.wikipedia.org/wiki/Orbital_period
My napkin math yields "as short as 1/3 Earth year", however I'm not sure I'd call that much^2 shorter, given some of the variety out there.
I'm eyeballing the graph in the linked blogpost, which has a dashed line for 4.5by solar-system age versus the optimistic "habitable" ranges. In particular, minimizing the distance gives (distance=0.4, star_mass=0.4) and trading off a bit for a more massive star (distance=0.5, star_mass=1.0).
The period of a circular orbit is proportional to (distance^3 / star_mass)^0.5 [0], so when I plug those pairs in I get orbital periods of ~0.4 to ~0.35 Earth years, respectively.
[0] https://en.wikipedia.org/wiki/Orbital_period
I haven't done math, but my mental prototype of a "tidally locked potentially habitable planet" TRAPPIST-1e, which has a period of six days. Maybe it is unusually fast?
https://en.wikipedia.org/wiki/TRAPPIST-1#List_of_planets
https://en.wikipedia.org/wiki/TRAPPIST-1#List_of_planets
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There is a wild sci-fi which imagines a tidally locked planet, and all the weird crap that goes on there. It was a pilot for a TV show which never got picked up, but you can watch it here:
https://youtu.be/mt90AYy8mvc
https://youtu.be/mt90AYy8mvc
Also a world in a 1970's French comic called Vinea (Yoko Tsuno –Roger Leloup)
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.
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.
IMHO, with kettles as you described variability of temperatures with rotating blowtorch will be lower. I don't think convection will be much different between two cases.
>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
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
Hm, but daytime flux is highly angle-dependent, whereas nighttime flux is angle-independent ...
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.
The only thing that changes throughout the day is the amount if inbound solar flux.
The Coriolis effect deflects the warm moist from the equator eastward, such that there is a wall of eastward wind right around the polar circles the blocks heat from reaching the poles. In a locked planet, the atmospheric current is more direct, so the heat distribution is more effective.
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The poles receive sunlight at a near 90 degree angle, ignoring the axial tilt.
Direct sunlight vs. spread over an area.
Direct sunlight vs. spread over an area.
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?
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...
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...
For Earth-sized planets solar winds don't have much affect. Geologic activity continuously pumps gas into the atmosphere and the planet has sufficient gravity to retain its atmosphere over long time periods. With a thick atmosphere, the losses from solar wind just don't make a dent, it's only for planets with an already thin atmosphere that it becomes a significant factor, and even then it's still not the main contributor. For example solar wind only accounts for about 5% of Mars' current atmospheric loss rate. The component of Mars' atmospheric loss due to the solar wind is about 100 grams per second, which over 10 billion years would remove less than 1% of Earth's atmosphere. Venus, despite having essentially no magnetic field and being even closer to the sun nevertheless has an incredibly thick atmosphere more than 90 times thicker than Earth's.
One of my bugbears about discussions of terraforming Mars really: any atmosphere we added to the planet to give it substantial surface pressure would take hundreds of thousands of years minimum to be lost in any quantity (i.e. by redirecting water ice comets to bombard it with Earth's ocean levels of new gases). Atmospheric loss just isn't a problem compared to the technical challenge of doing the comet redirect (which is actually the most plausible part of the enterprise, compared to the monster which would be developing an ecosystem on a barren planet that stabilizes at a human-habitable point of usefulness and isn't just "walls of sulfur algae" for a few thousand years.
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.
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).
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.
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.
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.
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.
"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.
Probably more importantly, an obvious adaptation in such an environment for prey animals would be to hide in dark places like caves where predators can't see you...so predators would develop with low-light vision for hunting where other predators couldn't and in turn....
Basically evolution tends to do every weird thing it can - and we can't know which would be likely to end up as traits on the dominant intelligent species.
Basically evolution tends to do every weird thing it can - and we can't know which would be likely to end up as traits on the dominant intelligent species.
Well, hiding under water is another obvious adaptation...but it does not automatically mean sea mammals evolved gills. They did evolve but in other ways. Some weird things just don't happen.
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.
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.
They’d likely have discovered caves or roofs at some point - and have some ability to see in dimmer light.
Not having celestial navigation would also make such exploration more difficult.
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)
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)
1) I am furious on Harrison's behalf. Great story, if rage inducing.
2) How does one precisely determine noon from the position of the sun? That feels like that would be a sloppy measurement, which would eclipse the error in the clocks.
2) How does one precisely determine noon from the position of the sun? That feels like that would be a sloppy measurement, which would eclipse the error in the clocks.
A planet that Spins only once in one of its years probably isn't dipolar
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.
I'm not so sure how easy it is to make a compass that works on a weaker field.
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?
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?
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.
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.
We navigated before compasses or any time of position system. Ships would travel well known routes from one place to another, with no care or knowledge of the actual topology. You knew you could go a straight line from point A to points B and C, and from C to D. Even if D turns out to be near by to A, all that existed were routes between points, and people would likely still travel to C to reach D.
It worked despite not really knowing where exactly anything was positioned.
It worked despite not really knowing where exactly anything was positioned.
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.
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.
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
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
China had the sea between China and Japan, and they had some nice oceangoing ships¹.
[1] https://en.wikipedia.org/wiki/Junk_(ship)
[1] https://en.wikipedia.org/wiki/Junk_(ship)
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> 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.
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.
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.
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.
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.
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.
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.
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.
Do tidally locked planets typically have a magnetic field?
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.
I imagine that a similar if somewhat more complex trick works on the day side if there’s a visible moon.
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.
So one would need timekeeping to track where you are in that cycle.
Indeed, but process is quite a bit slower, so you could likely get away with a worse clock.
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.
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.
An even more extreme version of this is life in the seas under an ice world like Europa.
Life is attracted to gradients; I would expect the most interesting behavior at the twilit ring.
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.
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.
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.
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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.
Very interesting idea ! I do wonder though if sufficiently complex life would ever evolve in an almost completely stable climate.
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.
Not to forget deep sea is also very stable in temperature. Being function of denseness of water.
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.
Occam's Razor and all that.
That’s not an explanation. It’s a restatement of what the great filter is trying to explain.
Occam's Razor says that we don't see any aliens because none actually ever exist.
Anything else is, alas, wishful thinking.
Anything else is, alas, wishful thinking.
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.
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.
Or maybe intelligence only exists here on earth. Any explanation for its uniqueness would be as evidence-free and tortuous as evidence for it's non-uniqueness. (Given that we have zero evidence one way or the other.)
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.
> ...you'd need extra reasoning to explain why earth is unique among thousands of trillions of planets
It is unique by definition, because we happen to live on it. There is no need to reason or explain anything, because it is a simple fact.
It is unique by definition, because we happen to live on it. There is no need to reason or explain anything, because it is a simple fact.
That meaning of unique doesn't have anything to do with the conversation at hand.
Again, that’s not an explanation. An explanation would explain why aliens don’t exist despite apparently ample opportunities for them to.
You are begging the question and reasoning circularly.
There is absolutely no evidence that there are "ample opportunities" for aliens to exist. Default assumption is that there aren't.
There is absolutely no evidence that there are "ample opportunities" for aliens to exist. Default assumption is that there aren't.
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?
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.
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.
It would just mean that life is improbable, which is perfectly plausible.
If you throw a coin 100 times, and it's always tails, it is plausible that this just happened randomly, but I doubt most people would agree that it's the simplest explanation.
Plausible, sure, but such a vast improbability itself requires what would have to be quite a complex explanation.
Why? It could be simply statistically unlikely, nothing complex about it.
https://en.wikipedia.org/wiki/Anthropic_principle
https://en.wikipedia.org/wiki/Anthropic_principle
One out of many quadrillions doesn't seem like much of a sample size, for the kind of statistical analysis you imply.
We don't know the prior probability. Life being common has the same probability as life being rare.
Exactly.
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.
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.
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
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 :(
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.
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.
Don't know about VR, but Space Engine on Steam seems to have tidally locked planets...
https://forum.spaceengine.org/viewtopic.php?t=206
https://forum.spaceengine.org/viewtopic.php?t=206
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.
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.
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.
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)
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)
And also that all our sister planets isn't like earth, and they all don't have life (as far as we observed). So it's another point for "not like earth"->"not have planet". Before those expeditions, we thought that fucking sun also has life on it https://adsabs.harvard.edu/full/2011JAHH...14..169C
"Earth exceptionalism" is still the best answer to the Fermi Paradox.
Maybe we're the first/only civilization in the galaxy. If so, then the question is, why? Maybe we're just the first and there will soon be millions of other civilizations.
But most likely, Earth is a fluke. Either something in its environment made it conducive to civilization or some random (and rare) evolutionary path led to civilization.
My uneducated guess is that microbial life is relatively common, but multi-cellular life is very rare and technological life is unique (at least in our galaxy).
Maybe we're the first/only civilization in the galaxy. If so, then the question is, why? Maybe we're just the first and there will soon be millions of other civilizations.
But most likely, Earth is a fluke. Either something in its environment made it conducive to civilization or some random (and rare) evolutionary path led to civilization.
My uneducated guess is that microbial life is relatively common, but multi-cellular life is very rare and technological life is unique (at least in our galaxy).
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"
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. :)
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. :)
That’s great news. How cool it would be to visit such a planet.
I like this refreshed model of the “eyeball” planet — perfect, endless beam reach sailing.
I'm interested in that six image chart. The insolation seems high.
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
(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
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.
[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.
i thought this was about the new DJ locks Tidal (the lame music service) put up. this is much more interesting :)
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.
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.
If you would have downvoted instead of leaving the Spotify AI DJ that's kind of how it works.
No you didn't. You just saw the worlds tidal and locking and figured you would make a cute comment about something clearly unrelated.
What a delight to read
imagine what tidal locking might do to the subterranean layers of a planet, compared to Earth's isotropic rotisserie
BTW, if the page author happens to be reading this. (loved the article BTW)
Your header image Screenshot_15.png is 2½ 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...
Your header image Screenshot_15.png is 2½ 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
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...
https://addons.mozilla.org/en-CA/firefox/addon/large-image-b...
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.
Also, there are some font size inconsistencies in the main body that should be looked into.
You're doing God's work. Thank you for caring.
Nothing upsets me more than people using PNGs when they should be using JPEGs, and vice versa
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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?
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.
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.
One of the references has a section on Implications for Observations of exoplanets.
https://iopscience.iop.org/article/10.3847/1538-4357/aa9f1f/...
https://iopscience.iop.org/article/10.3847/1538-4357/aa9f1f/...
> 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.
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.
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.
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.
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!"