Hurried Thoughts: You're Wrong About Tidal-Locking
worldbuildingpasta.blogspot.com
worldbuildingpasta.blogspot.com
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!"
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.
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.
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
The only thing that changes throughout the day is the amount if inbound solar flux.
Direct sunlight vs. spread over an area.
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...
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.
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 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.
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.
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.
It worked despite not really knowing where exactly anything was positioned.
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.
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.
I imagine that a similar if somewhat more complex trick works on the day side if there’s a visible moon.
So one would need timekeeping to track where you are in that cycle.
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)
I'm not so sure how easy it is to make a compass that works on a weaker field.
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.
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.
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.
Occam's Razor and all that.
Anything else is, alas, wishful thinking.
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.
There is absolutely no evidence that there are "ample opportunities" for aliens to exist. Default assumption is that there aren't.
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.
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.
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.
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.
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.
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.
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)
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).
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. :)
(The Drake equation is a probabilistic argument used to estimate the number of active, communicative extraterrestrial civilizations in the Milky Way Galaxy.)
[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.
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.
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
2.6% the size of the original.https://addons.mozilla.org/en-CA/firefox/addon/large-image-b...
https://iopscience.iop.org/article/10.3847/1538-4357/aa9f1f/...
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.
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 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.