How likely do you think it is that terraforming satellites of large gas giants are better than terraforming Mars?
Many satellites have an atmosphere similar to that of the Earth. Why then do we want to go to Mars with worse conditions?
There was news recently that NASA is preparing to collect soil samples from Titan. I wonder how soon the mission to Titan will begin.
Titan has protections (nitrogen atmosphere and Saturn’s magnetosphere) from galactic cosmic rays, that Mars does not.
Welcome to the SDMB, @Ethan13
Please take the time to read the category descriptions. You posted this in Cafe Society, which is our forum for artistic disciplines (art, music, cuisine, etc). Since you are seeking opinions about the likelihood of terraforming, I have moved this to our IMHO category.
Again, welcome, and we hope that you enjoy your time here!
I’m not sure the Taloids will just let us terraform Titan…
Terra-forming would be much more expensive than establishing a colony so we’re probably still a ways off (not to mention it taking decades, if not centuries). It’s still an interesting option though.
I don’t think we yet have a good understanding of how many satellites orbiting the same body interact with each other. Two planets coming close to each other = chaos and destruction. If two satellites can affect each other in the same way it might not be as safe as it appears.
Nope; we don’t:
“Many” satellites have an atmosphere similar to that of the Earth?! Titan is the only one with an atmospheric pressure anywhere remotely close to that of Earth’s, and it’s surface temperature is a cozy −179.5 °C. Maybe if you replaced the entire atmosphere with a strong greenhouse gas like methane it could reach human-livable temperatures, but then what is the point of setting up a colony there when people have to wear spacesuits to go out every time?
IMO the probability that humans can terraform Mars to Earth-like conditions (within a reasonable timeframe) is already highly remote, the chances to do the same for Titan are astronomically lower than that still. The truth hurts: even if humans scar the face of the Earth with wars and pollution, it’ll still be more livable than anywhere else in the Solar System.
No Jovian or Saturnian moons have “an atmosphere similar to that of the Earth”; in fact, Titan is the only moon in our solar system which has an atmospheric density comparable to Earth (~1.45 bar); however, the composition of the atmosphere is nothing like that of Earth, being approximately 97% diatomic nitrogen (N2), 2.7% methane (CH4), ~0.2 diatomic hydrogen (H2), and traces of other complex hydrocarbon gases. There is no free oxygen in the atmosphere and no significant oxygenated atmospheric compounds. There is very likely to be oxygen-bearing water ice in the strata of the surface, albeit probably buried under oceans of liquid methane and ethane and frozen to the hardness of granite by the extreme cold; with a surface temperature of 94 K (−179 °C) it would take an enormous amount of heat to produce liquid water or livable surface temperatures, and because of the distance from the Sun (the aphelion of Saturn is 1.5M km (10.1 AU) and perihelion is 1.4M km (9.0 AU)) the amount of solar irradiance is ~1% of that at Earth orbit, so using any kind of large mirror or lens to focus sunlight is an exercise in futility.
All of that being said, Titan is a fascinating target for planetary science, and is the most likely prospect for extant extraterrestrial life, although a metabolism capable of functioning at those temperatures would no doubt be very different biochemically from any life on Earth. Further missions to explore Titan (and Enceladus with its subsurface liquid water oceans and tidally-driven geological activity) are definitely desirable in terms of understanding the conditions under which extraterrestrial life could emerge, and are fascinating in their own right compared to the geologically inert Mars. Indeed, current thinking in astrobiology is that life is equally if not more likely to emerge in large satellites of gas giants rather than on ‘Earth-like’ planets because they do not require the same special conditions (e.g. being in a ‘Goldilocks zone’ of stellar insolation to provide surface water, a powerful geomagnetic field to maintain an atmosphere) to provide habitable conditions, at least for a liberal interpretation of ‘habitable’.
But we are not going to terraform Titan, or any other planet or moon in the solar system for the simple fact that the amount of energy required to do so is literally astronomical even if we had some technical means to do so, and by the time we have a sufficient grasp upon such energies it is likely we will have the ability to modify the 'human; (or rather, post-human) form into something that can survive the conditions and ravages of interplanetary space rather than desperately trying to make non-habitable spaces resemble Earth.
Stranger
IANA planetary scientist or anything like that.
I don’t want to minimize the difficulties of terraforming Mars, or the differences between Mars and Earth, but Mars is reasonably close to Earth in terms of overall composition. As on Earth, the surface of Mars is mostly made out of rock (specifically igneous rock). If you got a friendly wizard with godlike powers to magically give Mars a breathable oxygen-nitrogen atmosphere (and warm it up a fair bit), you would have a place with breathable air over a bunch of rocks and sand, not too different from various places on Earth. (There are differences in soil chemistry that would probably have odd and maybe somewhat unpredictable effects on the resulting environment.)
Titan is a very alien and different place. It’s vastly colder than Earth–sunlight out that far is maybe 1% the intensity of what it is here, and surface temperatures are nearly 300 degrees below zero Fahrenheit–and the whole place is just a totally different kind of world. In some respects, it is oddly Earth-like (or Earth is oddly Titan-like): Dense atmospheres, a complete water cycle (on Earth) or “methane cycle” (on Titan) of vapor/clouds, liquid rain, and surface liquid (rivers and lakes). You get some very familiar-looking landforms on Titan:
But the surface of Titan isn’t mostly made of rocks as you would find on Earth (or Mars). There are “rocks” down there under the surface of Titan, but a lot of it is water–maybe as much as half water–but frozen so hard out there that it acts like a rock. There may be liquid water (mixed with ammonia) as a subsurface layer; we might call that an “ocean”, but in some ways it’s more like a “mantle”, of “molten ice”. If your friendly wizard with godlike powers magically warmed up Titan to Earth-like temperatures (and gave it a breathable atmosphere), I suspect it would probably largely melt, and you’d wind up with a very deep ocean covering the whole surface. (And that’s without even getting in to where all the methane and ethane and other stuff would wind up going.)
This is a little misleading. The three-body problem, or more generally an N-body problem, is not solvable by closed form calculation (that is, you cannot derive something like Kepler’s laws for the interactions of three or more bodies the way he did for two), but they do follow Newton’s laws of gravitation, or more precisely, the reduced subset of Einstein gravity but since the effects of general relativity are not of significant concern for celestial motion around normal-mass stars and planets Newton will suffice. It is possible to simulate the evolution of even a complex system with high precision to the limit of perturbative effects, and generally speaking planetary motions and those of established moon systems around Jupiter and Saturn are sufficiently stable that it is possible to calculate positions of the major satellites for hundreds or thousands of years with great precision by using iterative methods with the gravitational field equation, e.g. Poisson’s equation for gravity.
The real complexity comes from having to select an appropriate iteration step to correctly model perturbative effects of orbital resonances which is an area of research onto itself, and of course nonlinearities in the geopotential field due to mass concentrations and asymmetries in large celestial objects, but this is again more of a computational problem than a theoretical one. But we certainly have the capability to assess stability of the moon system around Jupiter or Saturn to be assured of its stability for centuries short of some unforeseen large Trans-Neptunian Object (TNO) randomly flying through the system and impacting a moon.
Stranger
Thank you all for such a quick response. There is one theory that says an interesting thing: If you make mistakes in the question or give the wrong answer, then this question will be answered faster. It appears to be true.
And your answers were really helpful to me.
It’s always useful to ask questions like this, and they’re interesting to address because there are both factual and speculative aspects to them.
With regard to a future NASA mission to Titan, the Dragonfly mission is planned to launch in 2026 and reach Titan in 2034, delivering a multi-rotor drone that will fly around examining the surface conditions and looking for prebiotic chemistry (or perhaps even signs of active biota), provided of course that funding is maintained. This is part of the New Frontiers initiative to develop more frequent planetary exploration missions at lower cost compared to the Discovery class “flagship” missions.
Stranger
So the obvious answer is to tow Titan into Earth’s orbit! After that, it’s all easy!
Every time I stumble upon a discussion of terraforming, I can’t help but think it has to be a lot cheaper and faster to marsform or titanform the colonists. We can’t even maintain the climate we have here on Earth. But we’re fairly adept at manipulating DNA and can even asexually reproduce ourselves barring ethical considerations. Creating a new human species that can withstand the environments of other worlds isn’t a technology that’s right around the corner, but it has to be a lot closer than the technology and resources needed to transform entire worlds.
I think Enceladus might be a better choice. Or grab Europa from Jupiter too and combine them.
Or just build a death star.
We’re not anywhere close to being able to “asexually reproduce ourselves”; we can shake & bake a fetus via in vitro fertilization but this still requires an ovum and spermatozoon, which is by definition sexual reproduction. Producing a transhuman form (e.g. a modified body but with a still-recognizable human brain and supporting organs) that can survive on the surface of Mars unaided is complicated to say the least; the lack of available oxygen makes respiration impossible, so such a form would either have to have some way of internally producing diatomic oxygen to support the brain and necessary metabolic processes, or it would have to be regularly supplied with oxygen. The environment of Titan is problematic for any Earth biochemistry because even if you can make tissues that are robust against such cold temperatures the rate of chemical reactions will be over an order of magnitude slower than on the surface of the Earth; it would almost certainly require some kind of ‘post-human’ form that no longer relies upon terrestrial biochemistry which is well into the realm of science fiction.
But yes, in comparison to being able to construct and maintain an entire ecosystem sufficient for human habitation, modifying the human form to at least accommodate conditions beyond the terrestrial environment is a necessary capability. Even if we could make the surface of Mars to be ‘Earth-like’ we’d still have to cope with the fractional gravity that is still likely to pose a long term health problem for unmodified humans, notwithstanding the various problems with radiation, environmental toxins and hazards, et cetera.
Stranger
This is what I was thinking of:
https://www.inc.com/lisa-calhoun/the-first-artificial-egg.html
Well, that is no moon, for sure.
I’m curious why you list Titan (and later, Enceladus) as most likely to bear life, rather than Europa. Titan or Enceladus are certainly chemically interesting, but if they have life, it’s “Life, Jim, but not as we know it”, due to the extreme cold. Europa, however, probably could support life as we know it (provided that there’s some suitable ocean-floor source of chemical energy, which would also be needed for any other outer moon).