"It is not apparent yet that such Rogue planets are regularly traded between star-systems and subsequently participate in serial evaporative events and the proposal may seem like a long shot, but on astronomical time scales the unlikely can become commonplace."
> We note, however, that if a significant fraction of these ejections involve hypervelocity planets, then the number still inthe galaxy may be notably reduced as these bodies would be traveling in excess of galactic escape velocities, and so could become inter-galactic planetary bodies (Beastie Boys, 1998).
"The Chthonian process effectively selects for retainment of water and carbon dioxide, which are heavy and tend to rain back down upon condensing in the upper atmosphere."
So earthlike planets would be more plentiful than otherwise. This could be a boon to scifi plots that entail conveniently breathable atmospheres. It would also tend to support the strong anthropic principle.
The central "alien" in the novel Blindsight (by Peter Watts) is, quite specifically, not this human-in-a-mask trope. One of the key points I remember (possibly not-quite-accurately) is that the various attempts that humanity makes to communicate with the alien could be construed by the alien to be attacks: bombarding it with the kinds of signals that we use to communicate.
It's a memorable point, making it plain that normality in our sphere of experience is something that's evolved through many needles' eyes over millions of years. Different human cultures can't even relate to each other very well, and we share 5-nines of that evolutionary history.
Fundamental 'human' values are likely entirely at odds with any alien life morality we ever encounter. Thou Shall Not Kill? What about an amoebic life-form that honors its ancestors by absorbing their protoplasm, thus retaining their memories? Honor Thy Father And Mother? An insectoid race may become adult by the brood attacking, killing and eating their parent colony thus proving their fitness. Thou Shall Not Steal? That one's easy: what if property ownership is an ideal unique to territorial monkey-troop creatures with strong attraction to bling (us)? Sharing tools and food may be fundamental to every other successful race in the galaxy, humans being some aberrant race of moral deviants that prosper despite all logic to the contrary.
Add to that: the speed of interaction. Even on Earth we have everything from Sloth to Hummingbird. How will we get along with Hummingbird aliens? Aliens that move and think at the speed of a Giant Sequoia?
Even a tiny mismatch could be disastrous. What if they perceived the world only slightly faster? We would speak at the very low end of their perception; our flickering lights and video images would drive them mad. We would appear slow and stupid in every personal interaction.
> Dogs can take in visual information at least 25 percent faster than humans
Something else mentioned in the Blindsight novel, and actually what gives the book it's title, is (as far as I know) a theory about the 'tension' between the conscious and subconscious parts of the brain; that there's the "lizard brain" essentially subconscious which is usually overridden by the conscious part. There's a passage in the book where the 'alien' is psychologically attacking a character causing them to go blind. The character, however, is still able to catch an item thrown to them because, whilst their conscious brain is unable to process, and therefore react to, visual cues, the "lizard brain" takes over and forces an almost subconscious reaction to catch the thrown item. The "lizard brain" is immune to the blindness-causing psychological attack (something along those lines).
Something about the visual bandwidth available via the optic nerve is rather huge compared to how much bandwidth the conscious brain can actually process. The "lizard brain" is basic, but can process the full spectrum of bandwidth available.
The 'tension' between these two systems in our heads is exemplified (in explanatory notes at the end of the book) in the scenario where one drops something hot (maybe from being held in an oven mitt) and the instant, sub-conscious reaction is to try to catch it, whilst the conscious brain has to process the individual scenario and attempt to override the default response because if we touch the thing, it will burn us.
It's god damn fascinating!
* Disclaimer: The above is my interpretation / memory, it may or may not represent what actually happens or what the author intended to convey.
Look at the earning potential of those with IQ 90 vs 110 - which is largely based upon the subjects speed of answering timed questions. Maybe some enlightenment there...
Woops! Sorry. That google search just leads to a plethora of racist dogma pages with pretend data labelling ethnic groups. I'd hoped for some data across a single population.
Anyway, we learned something from that. Alien races with real significant differences will be treated vastly differently. Just like we unfairly treat one another over insignificant differences.
Trees see the world as we see time-lapse photography. There's a line from a Terry Pratchett (I think) book that says something like "The trees wondering who keeps switching the lights on and off".
(I can't find the actual darn quote).
It's poetic. Our time scale is trivial in the scope of the universe, whilst quantum time scales are trivial to ours.
It's the relatability to the audience that mandates they have human faces. ... because humans can only interpret the facial expressions and emotions of other human faces.
Star Trek was never meant to be Sci-fi so much as soap opera in space.
Star Trek was ever meant to be Sci-fi (search how Roddenberry and Asimov became friend). Soap opera in space is what CBS want it to become because it is so mush easier to write for (see Kurtzman-verse).
Maybe, but in animated things (like rick and morty) they, occasionally, have aliens that are vaguely essentially anthropomorphic animals and give those expressions.
So it's not entirely.. human. My point being that we can have the expressions of a human face on a non-human face
> My point being that we can have the expressions of a human face on a non-human face
To bring up the example of the octopus again, you can still get some sense of "expression" like anger etc. when they change their skin colors, without having a relatable face at all.
Or something more common: Dogs wagging their tails, cats pointing their ears, and so on.
I think you may be mixing up the causation. How probable our universe is, we'll never know (until we can see other universes). We do know that in this universe, life exists. Thus our universe has to be "fine-tuned" for us to exist because we do.
As for the universe "favor"ing life, that doesn't really make sense either. I think it's safe to say the universe favors stars, gas giants, black holes but it's pretty hard to say the universe favors life when it's only given us ourselves as an example.
> Thus our universe has to be "fine-tuned" for us to exist because we do.
Because we of course do not exist in this universe because we're fine tuned to exist in it.
I can't think of a better way to describe it than the late Douglas Adams did :
“This is rather as if you imagine a puddle waking up one morning and thinking, 'This is an interesting world I find myself in — an interesting hole I find myself in — fits me rather neatly, doesn't it? In fact it fits me staggeringly well, must have been made to have me in it!' This is such a powerful idea that as the sun rises in the sky and the air heats up and as, gradually, the puddle gets smaller and smaller, frantically hanging on to the notion that everything's going to be alright, because this world was meant to have him in it, was built to have him in it; so the moment he disappears catches him rather by surprise. I think this may be something we need to be on the watch out for.”
Isn't this the distinction between the Strong Anthropic Principle and the Weak Anthropic Principle?
WAP: we're going to see selection bias in our universe because the preconditions for life must have been satisfied for us to exist within it.
SAP: all universes must satisfy the preconditions for life because cogito ergo sum -- the definition of existence requires life to perceive it.
I've probably sold SAP short because my own model of existence doesn't require perception, but clearly by this point we're well within the realm of philosophy.
The Weak Anthropic Principle from my understanding is simply that intelligent observers are possible. There's no implied likelihood or selection bias. Simply it's possible in our universe.
I'd agree with this framing.
As for the SAP, I personally find it somewhat meaningless. If that's how you define existence, then you're correct by definition.
If you believe a whole universe's existence requires perception to say it exists, I find that somewhat ridiculous. The universe came first and then came life.
Do things just pop into existence as we perceive them? And as we perceive more, does more stuff just pop into existence like all of the recently discovered lifeless exoplanets? Did those not exist until we spotted them?
I strongly believe trees fall in the forest and make sounds whether or not someone is there to hear. If you define a sound as having to be heard, then you're only correct through your own definition.
Well, I offer dwarf fortress as a potential model. When you start a new world in dwarf fortress it will automatically generate a history for that world. There are a lot of games that pretend to be multiplayer but in reality are just filled with bots. Maybe our world is like that and everyone gets their own world.
No, that's not right. Latin has a separate copula --- sum, est, and so on. What gives Latin its terseness is that it supports dropping words implied by context (like the copula in many contexts) and that it's highly inflected, allowing single words to communicate grammatical information that we need word spam to spell out in English.
Uh, yeah, what you said. I'm not a linguistic expert so my experience with this is just "that's what it does" rather than "you can drop copulas" ;) Another one of the nice ones is that you can drop pronouns from context too–compared to English the Romance languages are pretty cool.
Our universe certainly has to allow for the existence of us because we exist, but I don't think it says much more than that.
It's easy enough to imagine on Earth that conscious life never formed and to imagine such without changing the laws of physics. I don't understand anything about our universe that guarantees the existence of conscious life, let alone guarantees multiple instances.
All we can really say for certain is that our universe allows for us. We really don't know how rare we are.
Our universe is "fine-tuned" to make it difficult for life on different planets, on different star systems, to find out about and communicate with each other.
I mean, you can calculate the probability of an abiogenesis event on pre-biotic Earth (or in our Universe in general), and then run the probability against the known number of solar systems/planets/atoms in the known universe.
Whether or not the universe favored life can be interpreted from the resulting improbability and the current results. Stars, gas giants, and black holes are probable.
How could you calculate the probability of an event that we have no idea about? We don't even know for sure that life originated entirely on earth itself - life or some crucial substances required for it could have originated on some other planet with conditions we know nothing about and been brought to earth on some meteorite; or it could have originated in some extreme conditions like a comet tail in close proximity to the sun.
I'm not saying these are necessarily plausible theories, but the fact that we can't discount them tells me enough about how likely we are to be able to calculate a probability for abiogenesis.
Life seeded implies that life still went through abiogenesis somewhere else.
I agree that we can't know the exact means, just that abiogenesis happened, but we can still calculate the probability of our conditions needing to occur for abiogenesis to happen.
Of course abiogenesis had to occur somewhere, but if we can't be sure that abiogenesis occurred on Earth itself, it means we don't have any clear idea yet of the conditions necessary for abiogenesis (apart from some a priori knowledge, such as needing to have carbon and water). Perhaps the necessary conditions are extremely strange.
We already know that Earth as it is today can't support abiogenesis, since it's not happening, and judging from the phylogenetic tree, it probably hasn't happened for more than 3 billion years. There is also a reason to believe that even if the Earth was once appropriate for abiogenesis, it only happened once, given that all life on Earth shares the same chemistry (though of course it is possible that there was simply no other way for life to be, or that there have existed other forms of life from other abiogenesis events, but that they simply have not survived).
I always felt like this simply lacked imagination.
If it were that there were parameters to tweak certainly many combinations would lead to degenerate solutions, but many that wouldn't and complexity would be found in many of them, some of it familiar, some beyond our imagination.
For mathematical dynamical systems (chaos theory) you'll find that you can tweak parameters. Some changes result in overall recognizable behavior, some changes result in completely different but still chaotic behavior, some changes result in boring, essentially empty solutions.
The universe is one big dynaimcal system; there's no reason to believe that if it is a function of certain chosen parameters, it is the only solution that would result in life.
How can a captured planet ever maintain a stable, almost perfectly circular orbit around the Sun, at a plane that almost exactly matches the rest of the planets? It's impossible. The only way this can be explained is if all the planets were created together at the same time.
Is there a succinct explanation of why some terrestial bodies in the solar system (Earth, Titan, Triton, Pluto) have mostly nitrogen atmospheres, but others (Mars, Venus) are mostly carbon dioxide instead?
I mean, aside from specifics about each, what's the pattern that you would apply to an arbitrary planet?
> Is there a succinct explanation of why some terrestial bodies in the solar system (Earth, Titan, Triton, Pluto) have mostly nitrogen atmospheres, but others (Mars, Venus) are mostly carbon dioxide instead?
For Earth, the answer is simple: life. In the absence of life, a nitrogen-oxygen atmosphere is thermodynamically unstable. Our best current understanding is that the atmosphere of the early Earth, before life developed, was mostly methane and ammonia, which are commonly observed in the atmospheres of the outer planets and their satellites. Once life developed, the methane and ammonia were gradually chemically converted by life to water and nitrogen.
For the others you mention, oxygen is not present, and the nitrogen is combined with methane (plus traces of carbon monoxide or carbon dioxide). I have not seen detailed thermodynamic calculations, but if there are very few oxygen atoms present, nitrogen plus methane should be thermodynamically stable. The unique feature of Earth as compared with these others would be the presence of a sufficient quantity of oxygen atoms to oxidize the nitrogen to ammonia in the early atmosphere before life developed.
For Mars, it is close enough to the Sun and small enough to make its temperature too high for it to retain significant amounts of nitrogen or methane (it has traces of both, IIRC), so CO2, which is significantly heavier, is the only significant component left.
For Venus, a significant amount of nitrogen gas is present (about four times as much as in Earth's atmosphere--Venus is significantly larger than Mars so its gravity can keep the nitrogen from escaping), but this is masked by the enormous amount of CO2 present (about 95 atmospheres worth), which AFAIK is believed to be due to all of the calcium carbonate in the surface rocks having been driven into the atmosphere due to a runaway greenhouse effect raising the temperature.
When solar system planets formed from stellar dust, do we assume that said dust was uniform in composition and merely position, solar dynamics and interplanetary dynamics such as collisions (formation of Moon) led to the differences in chemical composition?
For example, it's the outer planets that are gas giants. Venus composition doesn't seem too different from Earth but it's much closer to Sol, so it's more exposed with much more energy absorbed etc.
> When solar system planets formed from stellar dust, do we assume that said dust was uniform in composition and merely position, solar dynamics and interplanetary dynamics such as collisions (formation of Moon) led to the differences in chemical composition?
According to wikipedia, Venus' atmosphere is about 3.5% nitrogen and its pressure is about 91 atmospheres. So, technically Venus doesn't have a lack of nitrogen (it appears to have about 3 times as much as Earth), it has an extreme abundance of carbon dioxide.
Something interesting I didn't know is that apparently Venus has almost no plain oxygen.
Mars, on the other hand, doesn't have much nitrogen. Perhaps that's attributable to the relative lightness of N2, which would be more prone to float off into space than the somewhat heavier CO2.
Venus has no plain oxygen because oxygen is reactive. It probably requires life to break apart CO2 and cast off the O2 into the atmosphere. Certainly it required life to do that on Earth.
I’m pretty sure we still have plants, though I admittedly haven’t been out of the house much.
A lot of carbon was also captured during the aptly-named Carboniferous Period 360-300 million years ago. Woody plants had just evolved, but microbes that could break them down had not. Thus, coal. An earlier drop in sea levels also caused carbonate (as in limestone, dolomite, and iron ores) to precipitate out. The combination of these effects pushed oxygen levels about 50% above present, allowing very large animals to evolve.
It's not totally impossible for coal to still form, but the conditions are far, far less favorable: microbes get everywhere and the woody plants have a lot less lignin now than they used to, which also makes them easier to decompose. So, yeah, we're pretty got what we got.
Interestingly, this has happened once before. There's a "coal gap" from about 250-230 million years ago during which little-to-no coal was formed in most places. I'm not sure if anyone is sure why; this is right at the time of the P-Tr extinction, so a lot was happening. One theory is that the ligninaceous plants went extinct or other conditions were much less conductive to coal formation.
(FYI: Not a paleontologist or anything like--just a scientist who liked dinos as a kid and remembered some keywords!)
"The cyanobacteria producing the oxygen caused the event which enabled the subsequent development of multicellular forms." Seems like it was ultimately a win.
I think it is due the magnetosphere shielding from solar wind. Earth has a strong magnetosphere, while neither mars or venus do. For titan, wikipedia says "Titan spends 95% of its time within Saturn's magnetosphere, which may help shield it from the solar wind.", not sure about Triton and Pluto but they are much further from the sun so that probably helps solar wind not strip away as much nitrogen.
It's not a pattern of ratio or composition, it's a pattern of the quantity of each individual component. The individual quantities then constitute the composition.
For CO2, the pattern is temperature. Titan, Triton, Pluto are well below CO2's freezing point so it stays on the surface as ice instead of atmosphere. At these temperatures, nitrogen is the heaviest abundant molecule that remains gaseous, followed by methane. If you're warm enough for gaseous CO2, you have it. The only exception is Earth and that's because plant life absorbed it and emitted O2 instead.
For nitrogen, methane, argon, the pattern is mass. Only Venus and Earth have enough mass to hold on to those, compared to heavier CO2. Venus and Earth have similar quantities of those. Venus's excess of CO2 comes from temperature high enough to evaporate carbon and oxygen from rock compounds.
Titan has enough mass to keep a decent nitrogen based atmosphere as well. It is probably closest to Earth with the exception that methane is a water analogue on Titan.
A planet formed in another star system would very likely have very different isotope ratios than one formed here. Earth has very similar isotope ratios for most elements to meteorites.
I know tidal curves have increase the moons orbit, I’m struggling to think of anything (outside massive collisions) that would cause planets to move closer to their stars, or move to new ones.
NO. If solar wind caused a gas layer to evaporate, Earth shouldn't have the atmosphere it does. This planet should be like those surrounding it. Those same solar winds/radiation would have made sure of that. The issue I have with this is the same issue I have with evolution. If conditions were not created to favor life why are we the only planet with any known life & which is perfectly suited to a variety of life? Do you really think that's a coincidence? Scientists are constantly coming up with one ridiculous theory after another to explain why no evidence of life has been found outside our planet instead of just acknowledging that this planet is unique because it was designed that way.
> This planet should be like those surrounding it.
I don't know. The theory of development of planet systems is too young for my taste, so it could take it wrong. I believe that Earth was born between Venus and Mars, as current theories claim, but I wouldn't bet my hand that science will not claim something else in the next 20 years.
> Those same solar winds/radiation would have made sure of that.
They are not the same for Venus, Earth and Mars. They are stretched and weakened as they go away from Sun.
> Do you really think that's a coincidence?
No, anthropic principle is good enough for me. I mean it not the perfect explanation, but much better than creation, because if I assumed creation, than I'd need to build a big complex theories about creators having no evidence at all. If we got some evidence, if that evidence allowed us to reason about "how creation was done", "which forces was involved", and so on, than I'd like to throw away anthropic principle and to start speculate about creators and daydream of stealing their power. Like some ancient bloke who stole fire.
Huh? No scientist claims to have ultimate knowledge of why there is life on earth. But to claim that Earth was created for life is leap too far. I mean we used to believe storms where conjured up by the gods because we didn't understand how they really are created. What you are saying is essentially the same. We don't know so it must have been created. You are essentially invoking the God-of-the-gaps fallacy.
It's a coincidence that a carbon lifeform like you is standing on a planet perfectly suited for carbon life, wondering at the chances of happening to be on the right kind of planet?
I don't remember that scene from Hitchhiker's Guide, but it must be in there somewhere. The collolarry to the whale wondering why it is hurtling down towards the surface of a planet..
I hear you. Intelligent and abundant life on a planet that is PERFECTLY suited for it is a coincidence? Maybe, but it's tough proposition for me personally.
It sounds a bit Velikofskian.