I would like them to find methane & oxygen in an atmosphere. I don't have a clue really, but I think that would be pretty convincing evidence of life. I expect that they are busy looking and we will get a result like that in the not too distant future - if the JWST can do it and if such atmospheres do exist in substantial numbers.
Methane has been detected on Mars, and is not regarded as proof of ‘life’. In addition to bacteriological sources of methane, it can be produced through geochemical processes. I am not sure which, if any atmospheric gasses would be proof-of-life.
IIRC, chemical bio-signatures are out of equilibrium chemicals: if some environment has only CH4 or only O2 that says basically nothing, but if it has both CH4 and O2 then (because these rapidly react to form H2O and CO2) the combination would suggest some process is creating methane and oxygen from water and carbon dioxide, which suggests[0] life.
[0] I don't know anything else which does this, but that's mostly because I'm a software engineer and my highest chemistry qualification is a 22 year old GCSE grade B.
Im not sure what proportion of the atmosphere would have to be a certain gas to spot it. In addition, JWST doesn’t have enough resolution to see small spots on an exoplanet. I don’t think JWST could spot earth-like levels of CFCs.
Exactly. Detecting CO2 is cool, but it's very stable and found in lots of places. Finding more reactive gases would be more exciting, because that might imply they're being replenished from somewhere, presumably either geological processes or life. And some gasses like oxygen don't really get produced by geological processes.
If we can go 1% the speed of light, a 70,000 year journey is roughly the length of time humans have been living in shelters. It's an extremely long time, but it's firmly a social and technical problem. The people who step off that spaceship will have nothing in common with Earth, and even if they spend 95% of their time in suspended animation not aging, they may very well not even speak the same language that their ancestors did when they left here.
A 7 million year period is very different. Humans split off from chimpanzees 7 million years ago. The people that step off that ship will probably not be human. Even with radiation shielding, even with genetic engineering, keeping genes stable enough to stay compatible with current humans is... unlikely. It's easy to say they could just have DNA on file, but the actual reality of that challenge is mind-boggling. How do you handle a space ship where you have to account for wind erosion in the hallways?
People think about space travel exactly in the same terms as the History of European Colonialism. Like exactly. Every first contact movie "take me to your leader" is right out of the letters to the king written by Hernán Cortez and Francisco Pizarro, looting the Aztec and by far the most gigantic, the Kechwa fortune after taking the Inca hostage. That's like 200 years of Chile's current gold production, and this is a mining country with modern technology to the point it exports eg explosives for mining. Just an insane amount of gold whose accounting was not possible to do correctly. Like doing the accounting of a casino from the movie Casino. Gold like it was iron ingots. Fucking stupid stupid amounts of wealth, all for going overseas.
So people think, OK, who plays the Europeans? Some movies say Earthlings do, other movies say aliens do. Either way, plunder and pillage. Like one movie, very enlightened, said the aliens just wanted our gold. That's wantable. But like think of it in terms of apes, like a primatologist. Aliens would be going somewhere with shit technology right? Well the real reason would be to get our nice biosphere, before we wreck it long-term ourselves. That they could want. So, for a rough handle for alien's interest in humans, look at primatology or study of cetaceans. Yeah we spend trillions on space travels, rockets, telescopes. I doubt we've even spent a billion on primatology. Cetaceans I think has cost more than a billion. There's just way more money and brains in whales than apes.
I think space colonization will be similar to European Colonialism but only for the Solar System. After that, it sucks. And it doesn't stop sucking for at least 700 light-years.
> I think space colonization will be similar to European Colonialism but only for the Solar System.
I think not. European Colonialism for the Solar System will be the first phase of becoming a race of people in tin cans.
When travel takes more time than building a working economy at the destination, it makes more sense to learn how to live a traveler's life then how to terraform planets to replicate Earth.
Just think about it. Space ship traveled for tenths of thousands of years and has reached it's destination. Who are the people on the ship? They are for many generations lived on a space ship. When they were kids they heard stories about living under an open sky on an outside of a spherical surface in a gravity well, but it is all like fairy tales. Not because they are false, but it is a shadow of an ancient memory. No one experienced this first hand, and no one talked with people experienced it. It is like Bible's stories, but even further in time.
So the question is: will these people think it is a good idea to leave space ship to try to build a fairy tale? They were content with living in a tin can not just for generations, but for whole epochs. Why they suddenly change their mind and decide that living under an open sky would be better than in a tin can?
I think that there will be different opinions, so some people will jump to building a fairy tale, while others just chill a little here near the star, and then move away from it, to a life free from all this solar wind wearing down the outer shell of their ship.
If humanity wants space colonization, then it needs to think about space ships where hundreds of thousands or millions of people can live. And these people pretty much will be space-ship people, believing that it is the true way to spend a life.
> People think about space travel exactly in the same terms as the History of European Colonialism. Like exactly.
This I agree with.
> I think space colonization will be similar to European Colonialism but only for the Solar System.
This I disagree. Without von Neumann machines, at best the initial colonisation of the Sol system will be like whichever human first found Iceland or Greenland, but only if they got there via a shipwreck.
If we do get von Neumann replicators soon enough to avoid that, we may just Dyson this system and go directly to every galaxy in our future light cone.
The von Neumann machines are a process. It has many different organs. von Neumann worked on the brain in particular, that was a big bottleneck and still is, others eg Henry Ford specialized in an analog of the muscle. The Industrial revolution at one point specialized in textiles, one of the many many things performed by the fingers of the only real unique organ humans possess, the human hand. But it took a huge amount of fingers finging, like people would spend so so so much time weaving, slaving away at the loom, replacing that function with machines to give everyone good clothes (everybody has good clothes), was worth I think...two fingers per person. It was also a finger-intensive process, the machine could remove fingers, machines still do, that's why that one industrialist specialized in hiring child labor for the machines and visited orphanage after orphanage, saying hey children have small fingers that's perfect for these machines.
And that ties into why we have ten fingers, like we have thirty-two teeth at adulthood and need some removed, that is after losing the first round of teeth in childhood. There's replacements. Some monkeys used for experiments need to be kept in cages, watching cartoons (meant for human children, same ones, they don't make special cartoons for the monkeys), and the monkeys (I wish I remembered what species this was) stop and stare at the screen, paralized. Keeps them pretty happy while they're isolated from each other in cages. Normally they're not kept in cages, except for this experiment, you know why? This experiment required them having all ten fingers, like humans, but if left hanging around as a group they bite each others's fingers off like in the first three minutes. Just to figure out who gets to fuck, basic pecking order, right off the bat. Ten fingers is like ten shirts. In Utopia Thomas More...well one of his characters, he specifically wrote that book within a book to defray responsibility...said if you have ten shirts you are a clotheshorse. Too many clothes. Because they had such a huge cost. A cost of drudgery, then performed by the mechanical loom. That's one organ.
von Neumann machine. Organ by organ.
Like can you imagine a whale telling another whale e=mc^2? Who gives a shit! Want a Nobel Prize you blowhole? Gotta keep hunting squid every day, that's the bottom line, philosophy (don't know the whale word for this) is for when both us whales are full. The human hand is what gives that the power it has, humans are busting open a bottleneck of life with our hands. I'm typing this with all my fingers. I couldn't do this by voice. It would come out different, not as spinal. In fact my hands are writing faster than my inner monologue. They absolutely have a life of their own.
Yeah shipwrecks. For sure there were people crossing the Atlantic via shipwreck, they could flat-out never make it back. Even then people could be disbelieving and say, "eh old Mariner's tale.". Nobody buys those stories, nobody buys the stories about sea monsters (whales intelligently ramming ships crossing their territory), everybody thinks sailors are full of shit. That's what happened with the Vikings, who did cross the Atlantic, but couldn't exploit it nicely (from the explorer's point of view) like the Hispanics. It's also because Vikings crossed before the Black Death, so they weren't infected with smallpox. Bioweapon. Back to the shipwrecks: this fact, that you can't make it back, was critical to the Atlantic Slave Trade: Africans had no hope of returning to Africa, once an African sold an enemy off to the Europeans headed for America, he had no worries of seeing that enemy return to Africa. That was key. A Colonial historian told me this.
Correct me if I'm wrong, but doesn't that have a peak speed of 0.9999961908c, thus a gamma factor of 362.3, and therefore the CMB ahead of you would be blue-shifted from 2.7 K to 989.1 K?
Not at all. But those 13 years are from the perspective of the people on the ship (also, from. Their perspective, the distance they travel is much much smaller). From the perspective of people on Earth, the ship arrives on that planet many thousands of years later.
Edit: actually, from the perspective of people on Earth, it will roughly arrive 700+1 years later.
bottomline, you get progressively closer to speed of light and time slows for you so you can cover larger and larger distance in local frame. problem is finding this 1G drive.
It's close enough to be useful for generational ventures, and in terms of one-way travel time, it takes much less than 700 years from the perspective of the ship to traverse that distance.
> in terms of one-way travel time, it takes much less than 700 years from the perspective of the ship to traverse that distance.
Only if either cruising at a large percent of the speed of light, or with constant acceleration. Neither of these is achievable with any technology we know exists, but neither is ruled out by current physics either.
Only if the ship is travelling at close to the speed of light, and we have no reasonable technology likely to be able to achieve that, especially for large vehicles.
For everyone imagining an industrial revolution 700 light years away - unfortunately WASP-39b isn't well suited:
"WASP-39 b is a hot, puffy gas-giant planet with a mass 0.28 times Jupiter (0.94 times Saturn) and a diameter 1.3 times greater than Jupiter, orbiting just 0.0486 astronomical units (4,500,000 miles) from its star"
Why would the presence of CO2 in the atmosphere ever be used to assume an industrial revolution in any scenario?
The atmosphere of both Mars and Venus are 95% CO2. Earth had plenty of CO2 before humans even existed. In fact, there were periods hundreds of millions of years ago where Earth had drastically more CO2 (up to 9000ppm vs 420ppm today) than it does today.
"Assume" is a strong word, but if we observed an exoplanet with free oxygen in the atmosphere and stable levels of bioindicators (methane etc) for a period, and then saw CO2 spike from nearly zero to significantly higher levels... well, it's evidence of something.
Maybe that's something we'll detect over the course of hundreds of years of observing, but the shear scale of the time of the universe makes the chances that some other alien species just happens to be going through an industrial revolution while we're around to observe it, are so astronomically small as to barely be worth considering.
In your example, an intelligent species in an industrial revolution would probably be at the bottom of the list of likely explanations, simply because of how statistically unlikely it appears to be.
It's diameter is ~112k miles, or roughly 2% of the distance to its star. It's hard to imagine the amount of chaos in that atmosphere. I would think all of the churn from the gravitational gradient would end up effectively tidally locking it?
Totally agree. Particularly if it becomes tidally locked and you end up with a ring-shaped habitable zone that's out of the direct heating/radiation of the sun and fed by convective currents coming from the cold side.
The jury’s out on that metaphysically speaking, but even if so that’s a rounding error of the rounding error. This handy chart breaking down the universe by subject area is a useful guide.
More, once we include the combinatoric number of music genres produced by certain grouping of heavy metals on the third cluster from a medium-sized, boring star the metal designates as Sol.
Doesn't this have to do with the formation of those elements? As in 'anything heavier than helium is a metal because it was formed in the explosion of a first generation star'? Rather than the chemical definition of what a metal is they probably should have used '2nd generation or later elements' but then again, computer programmers call little boxes with wires attached to them 'mice' and nobody bats an eye (and in fact, that use has now become commonplace).
Ok, completely unrelated, but here's a riddle: how many nuclear reactions are there in a thermonuclear bomb?
1. Fission of the plutonium pit
2. Fusion of a small amount of deuterium-tritium at the center of the plutonium pit (designed to be a source of extra neutrons to boost the yield of the plutonium fission)
3. Fission of Lithium-6. Yep, Lithium can undergo fission when bombarded with neutrons. It can't sustain chain reaction, but it's fission nonetheless. The main idea is to generate Tritium, which goes into the next phase, but the energy generated during the fission of Lithium is nothing to sneeze at. Pound for pound, it generates about as much energy as the plutonium.
4. Fusion of the hydrogen (tritium produced from the previous step, and deuterium that's stored in the form of Lithium Deuteride from the beginning)
5. Fission of a rod of plutonium in the middle of the cylinder containing the hydrogen (fission is returning the favor and boosts the fusion reaction)
6. Fission of the uranium temper. The main point of the uranium temper is to be heavy and contain the nuclear reactions for a tiny bit of time, so more generations of reactions can happen, but the secondary outcome is that some of the U-238 nuclei will undergo fission when bombarded by the neutrons from the inside of the bomb.
