https://www.livescience.com/65470-strange-martian-water-cycle.html
There's a hole in the Martian atmosphere that opens once every two years, venting the planet's limited water supply into space — and dumping the rest of the water at the planet's poles.
[...]On Earth, summer in the Northern Hemisphere and summer in the Southern Hemispheres are pretty similar. But that's not the case on Mars: Because the planet's orbit is much more eccentric than Earth's, it's significantly closer to the sun during its southern hemisphere summer (which happens once every two Earth years). So summers on that part of the planet are much warmer than summers in the Northern Hemisphere.
When that happens, according to the researchers' simulations, a window opens in Mars' middle atmosphere between 37 and 56 miles (60 and 90 kilometers) in altitude, allowing water vapor to pass through and escape into the upper atmosphere. At other times, the lack of sunlight shuts down Martian water cycles almost entirely.
https://doi.org/10.1029/2019GL082839 Dmitry S. Shaposhnikov, Alexander S. Medvedev, Alexander V. Rodin, Paul Hartogh. Seasonal Water “Pump” in the Atmosphere of Mars: Vertical Transport to the Thermosphere (pdf; paywalled)
(Score: 1, Funny) by Anonymous Coward on Sunday May 19 2019, @02:18PM (4 children)
Humans weren't satisfied ruining their own atmosphere but had to punch holes in the martian atmosphere with their probes too. The weakened atmosphere is now letting the water leak out. Basically, Mars is crying.
(Score: 0) by Anonymous Coward on Sunday May 19 2019, @02:47PM
Start the reactor. Free Mars!
(Score: 2) by Runaway1956 on Sunday May 19 2019, @03:37PM
The asshole drinks a lot. He pisses a lot, as a result. What else did you expect?
(Score: 2, Funny) by Rupert Pupnick on Sunday May 19 2019, @04:00PM
Somebody call Elon Musk! Fast!
(Score: 0) by Anonymous Coward on Sunday May 19 2019, @04:20PM
hurr durr gimme back muh CFCs! librul hoax!
This post paid for by the Sunscreen Manufacturer's Alliance.
(Score: 3, Interesting) by The Shire on Sunday May 19 2019, @03:35PM (38 children)
The atmosphere on Mars has a max pressure of less than .2 psi. This article makes it sound like there is an appreciable atmosphere on Mars at all, which there isn't. To give you an idea of how thin the atmosphere is ALL THE TIME, if you were in the middle of one of the most violent sandstorms the planet can conjure up, you wouldn't feel it. The "winds" at 100mph on Mars are equivalent to roughly 10mph on Earth. In other words, that violent sandstorm in the beginning of the movie "The Martian" could NEVER happen.
Bottom line - the water on Mars is pretty much free to leave anytime it's warm enough and exposed. The water that remains on Mars is buried under rock or dry ice. Anything on the surface will vent away whether there is a "hole" or not.
(Score: 0) by Anonymous Coward on Sunday May 19 2019, @03:42PM
Mars doesn't even have a troposphere.
(Score: 3, Interesting) by JoeMerchant on Sunday May 19 2019, @04:16PM (36 children)
Which, I thought, was the point of the article: they've now defined how often it is warm enough and exposed - which isn't often.
It's all relative - 0.2 is only 1/73rd of Earth's sea level pressure, 1/50th of the pressure at 10,000 feet - which is more or less comfortably habitable, here. For reference, Venus' atmospheric pressure is 93x Earth's, Mercury's (when you can find it) is around 10^-14th that of Earth - much closer to "no atmosphere," in my estimation.
Will we be free-breathing on Mars without terraforming or genetic modification? Unlikely. Are there enough useful gases in Mars' atmosphere for plants to respire? I think so - growth would be slow, but if we have enough patience, and understanding of things like Mars' thin water cycle, I think we could turn it into a much friendlier place to build a dome home.
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(Score: 2) by The Shire on Sunday May 19 2019, @04:51PM (34 children)
[quote]Which, I thought, was the point of the article[/quote]
Except it wasn't - the point was that a "hole" sometimes opens up in the "atmosphere" that allows water to escape. The falacy is that water is ALWAYS able to escape regardless of this "hole". A hole punched in something that is almost not there to begin with is a trivial change.
[quote]It's all relative - 0.2 is only 1/73rd of Earth's sea level pressure, 1/50th of the pressure at 10,000 feet - which is more or less comfortably habitable[/quote]
.2 psi is the equivalent of 32,000ft on earth. I promise you, that's not anywhere close to "more or less comfortable", in fact is LETHAL. That's more than a mile higher than the peak of Mt Everest, and how hospitable do you think that is to life? No plant can survive that kind of low pressure and low temperature, let alone animal life. The idea of teraforming Mars is reserved for science fiction novels, not reality. We have neither the power nor the technology nor are the resources available on Mars to appreciably change the surface environment. It will never be any friendlier to dome life than it is right now.
(Score: 2) by JoeMerchant on Sunday May 19 2019, @05:37PM (33 children)
Depends on your timescales, and optimism. We have the technology already to redirect water-ice from the Oort cloud into Mars collision, what we lack is the economic will to do so. If you are willing to wait 2-300 years for nuclear/solar powered ion engines to nudge ice-balls down into Mars collision, we could have started that project 20 years ago. ~5000 years later (less, if you up the investment), we just might have enough water/atmosphere on Mars to get serious about using modified Earth plants/algae to clean up the CO2 / oxygenate the place. Will the pressure ever get to anything that humans can breathe "outdoors"? Maybe not, but even at 0.5 psi, if the content of the air includes oxygen and water, that makes planet-wide colonization much, much easier.
Of course, if you live in the real world, the odds of any kind of technological society continuing 5000 years forward from the present day should seem pretty slim, but... if there's even the slightest chance, having a nicer 2nd planet to populate would be a good thing.
Duh?
🌻🌻 [google.com]
(Score: 3, Insightful) by vux984 on Sunday May 19 2019, @05:59PM (17 children)
But what keeps the water there? You warm mars up a bit and the water vapor will just spin off into space again. The core issue with terraforming mars isn't the atmospheric pressure, and it isn't the lack of water. It's the lack of gravity.
(Score: 2) by JoeMerchant on Sunday May 19 2019, @06:09PM (9 children)
If you really want to fix that, start crashing iron asteroids in from the nearby belt....
On the other hand, if you're more into short term (million year) solutions, it takes a long time, in human scales, to boil away an ocean.
🌻🌻 [google.com]
(Score: 0) by Anonymous Coward on Sunday May 19 2019, @06:59PM (2 children)
Because if it boils off mars, but stays in orbit of the Sun, you aren't really losing anything, and it may be collected by other comets or stellar objects, or be available for future technology to recollect.
Having said that: Finding a way to increase Mar's spin to help improve gravity should be considered a worthwhile investment. Personally I think we need to get exploratory mining activities going on Mars first to make sure there is nothing there of historical or technological interest before we start deorbiting asteroids (iron ore or otherwise) into mars in either an attempt to increase its mass or to improve its spin characteristics to better hold an atmosphere.
As others have said previously, Venus is the better short term colonization attempt, since lighter than air craft can be much more dense than on earth while remaining at earth atmosphere. There would still be acid mitigation/resistance to concern ourselves with, but the right genetically modified organisms could metabolize the hostile atmosphere of Venus making it more suitable for human exploration and habitation over time.
(Score: 2) by takyon on Sunday May 19 2019, @07:41PM
Venusian airships are one thing, but I wonder what we could accomplish by blocking some sunlight from reaching Venus. Could be a good test case for Earth geoengineering.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 0) by Anonymous Coward on Sunday May 19 2019, @08:53PM
It might be a stupid question, but how does increasing Mars' speed of rotation increase gravity and atmospheric pressure?
(Score: 3, Informative) by takyon on Sunday May 19 2019, @07:49PM (5 children)
The mass of the asteroid belt is around 4% of the Moon's mass. We might be better off smashing them all onto Ceres, or using them where they are.
We might be able to get 0.9 Earth masses from the Kuiper belt, but that's a tough project and might also be the wrong move. Creating spinning 1g space habitats is a lot easier than increasing the mass of Mars by an order of magnitude. It would also be wasteful to move all of that over millions of years only to have it ruined by a luminous Sun (pre-red giant phase).
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by JoeMerchant on Sunday May 19 2019, @07:59PM (4 children)
For the local asteroids, you're probably right - melt and inflate and spin, then live on the inside (ala Niven, I think he wrote that in the 1960s...)
I didn't realize the asteroid belt was so thin... I guess all those elementary school not-to-scale illustrations have skewed my thinking. Still, there should be plenty of ice to give Mars a respectable ocean if we can harvest the Oort, and that would take orders of magnitude longer to boil off into space than it does to collect on the surface. May we be blessed to not kill ourselves long enough for the boil off to be a problem.
🌻🌻 [google.com]
(Score: 2) by takyon on Sunday May 19 2019, @08:07PM (3 children)
Let's try releasing sulfur hexafluoride and other potent greenhouse gases on Callisto first.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by JoeMerchant on Sunday May 19 2019, @10:40PM (2 children)
Jupiter gives me the hebie jebies. I like quiet space, not intense magnetic vortex space. We're so dependent upon clever contraptions when we're out of our natural ecosystem, and those clever contraptions are quite vulnerable to magnetic flux and strong EM fields.
🌻🌻 [google.com]
(Score: 2) by takyon on Sunday May 19 2019, @11:09PM (1 child)
https://en.wikipedia.org/wiki/Callisto_(moon) [wikipedia.org]
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 2) by JoeMerchant on Sunday May 19 2019, @11:24PM
At least that's better than more affected, unless it lulls one into a false sense of security...
And I'd really like to know more about the stability of that belt than we do so far...
If NASA knows something I don't know about the arrival date of practical fusion power, yeah, sure, the outer planets are where the resources are at... until we've got a whole lot more cheap, controllable energy - I'd like to stay closer to the big familiar fusion reactor we evolved under - maybe even in Venusian orbit.
🌻🌻 [google.com]
(Score: 2) by takyon on Sunday May 19 2019, @07:37PM (6 children)
Crash Venus into Mars, and the resulting planet should have about 1 Earth mass.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 3, Insightful) by JoeMerchant on Sunday May 19 2019, @08:05PM (5 children)
That might be approaching science fiction - not attainable with today's engineering and economic limits.
Sadly, giving Mars an ocean is merely political fiction: sit down and calculate what could have been done with 50% of the U.S. Aircraft Carrier fleet budget for the past 50 years. Not saying the ocean would be there yet, but I am saying that even if we didn't have additional technological breakthroughs (which we undoubtedly would have), we could have a fleet of comet-pushers in operation, with the first collisions already happening by today, and a significant surface ocean on Mars within a few hundred years.
🌻🌻 [google.com]
(Score: 2, Insightful) by RandomFactor on Sunday May 19 2019, @08:54PM (1 child)
If you can retroactively and proportionally reduce the other militaries in the world and reassign those funds to the same goal, I'm pretty good with this.
В «Правде» нет известий, в «Известиях» нет правды
(Score: 2) by JoeMerchant on Sunday May 19 2019, @10:52PM
Through most of those 50 years, most other navies with aircraft carriers only had one... it's hard to mothball half an aircraft carrier ;-)
Seriously, though - it is purely political fiction. There's no way, in the world I have lived in, that the US would have done anything other than the insecure child: "my stick is bigger than all your sticks put together" thing, not because the US is special, but simply because we could. Virtually any other nation put in our position after WWII would have done the same, except perhaps Tibet, but, then, it is virtually impossible that Tibet would have gotten itself into the position that the US did after WWII...
Maybe, with this whole nearly free instant global communication for everyone thing, if we can continue to make forward progress for another few hundred years, we might, as a species, mature to a point where we can all put our sticks down and work together to accomplish greater things than bashing each other over the head when one of us steps out of somebody else's idea of a line. If we don't, and E.T. does come to visit because they noticed all those H-bomb blasts and I Love Lucy broadcasts, our self-bashing sticks aren't going to be much good at convincing E.T. to not settle in and share our resources while showing us how good their rabble control methods are. If we at least have some experience getting around our own solar system and doing more than taking pictures, we just might be able to fend off an unfriendly visitor or two from light years away.
🌻🌻 [google.com]
(Score: 2) by vux984 on Tuesday May 21 2019, @11:16PM (2 children)
"sit down and calculate what could have been done with 50% of the U.S. Aircraft Carrier fleet budget for the past 50 years"
Nothing. Absolutely nothing. Voyager 1 hasn't reached the oort cloud yet. And it won't reach it for another 300 years. And it will take 30,000 years to come out the other side. The oort is huge, and its *sparse*. You'd never know you were in it, unless someone told you. If you were sitting on an object in the oort, the distance to the nearest object might easily be bigger than the distance from the earth to the sun.
Even if we'd launched a bunch of missions 50 years ago, they'd still be hundreds of years from getting there. And once there, assuming they could do their thing, they'd have an enormous trip to get to the next one.
(Score: 2) by JoeMerchant on Wednesday May 22 2019, @02:30AM (1 child)
Each of the 11 US aircraft carrier groups cost, roughly, the same to operate as NASA - today, you can think of NASA as our 12th carrier group if you like.
With 6x the budget, we would have more than 12 Voyagers. Projects like advanced ion engines and other concepts wouldn't just be theoretical papers and graduate student projects at Cal Tech.
You don't have to go all the way to the Oort cloud to find icy bodies that can have their orbital velocity reduced, dropping them low into a Mars intercept trajectory - the bodies themselves are fuel, you just need to send enough energy (Plutonium? Thorium?) to apply the desired delta-V. Oh, and a ton of engineering - yeah, maybe 5x as much engineering as has been invested in current launch vehicle programs.
And, while we were at it, maybe we could reduce our carrier group footprint even more, since large rocks precision dropped from orbit are a pretty serious deterrent. Practice drills on the moon could make all kinds of pretty patterns, and of course a few demonstrations on unpopulated places would be necessary to prove out theories about atmospheric re-entry. No isotopes spread, no lasting effects, just big impressive flash-boom and done.
Would have to get serious about cyber-security, though. Hijacking of the rock-throwing robots would be a bad thing.
🌻🌻 [google.com]
(Score: 2) by vux984 on Thursday May 23 2019, @12:41AM
"With 6x the budget, we would have more than 12 Voyagers. Projects like advanced ion engines and other concepts wouldn't just be theoretical papers and graduate student projects at Cal Tech."
Sure. Maybe. Although a lot of our advancement is enabled by our advances in telecommunications and computation; which is hard to imagine progressing at a much faster rate. So, absolutely I think we'd be ahead of where we are now in space, but really... I think you are overly optimistic if you think ion drives we built 40 years ago would be throwing snowballs at mars and already landing them. Or even "advanced" ion drives 20 years ago. ion drives would take would take centuries to accomplish what you are talking about. Comets orbiting at effectively random trajectories at 100s of kilometers per second ... diverted to a collision course with Mars. Using what? 50 - 100N thrusters (a number of orders of magnitude stronger than anything we have so it would be 'advanced' by your definition. (And about on par with the amount of downward force applied by gravity against your hand holding out a 2lb bag of onions. 0.9kg * 9.8m/s^2 = 88N ). And where are we getting the power? Solar ... at 2000 AU from the sun? Nuclear ... it would have to be nuclear.
And seriously... if we'd put all the R&D money into nuclear instead of NASA or carrier groups THAT might have changed the world too. But part of the problem with Nuclear is that all the R&D money that went into it before 1945 DID change the world...and in particular what the world thinks about nuclear. And Chernobyl didn't help in the 80s either although that reactor was still tech from the war era. :/
"Practice drills on the moon could make all kinds of pretty patterns, and of course a few demonstrations on unpopulated places would be necessary to prove out theories about atmospheric re-entry."
A doomsday weapon they can see coming for months or even years or even decades, before it strikes gives them plenty of time to evacuate, deflect, and above all counterstrike...
Meanwhile your scenario dramatically reduces the American global military projection. It's hard to extrapolate what global politics would be like without that american doctrine. Would the USSR have collapsed, would OPEC include Russia or Mexico? Would Israel have fallen to its neighbors, would China or Russia have annexed North and South Korea...and Japan? You can't just remove 100s of billions in military spending without considering that other balances of power might have shifted. The world might be a very different place.
It's a terrific thought experiment. And great fodder for good hard sf. But at the end of the day, you CAN'T just say we would have oceans in the works on mars based on eliminating half the US navy. For all we know the lack of American military projection has led to nuclear war with the USSR 30 years ago; we've abandoned space in favor of hydroponics solutions to feeding the survivors while we cope with Nuclear winter and fallout. On the plus side the war decimated the population and wiped out a good chunk of industrialization; and between nuclear winter's cloud cover and acid rain destroying grazing ranges the cattle population has declined dramatically too. The temperature is falling, and carbon emissions have dropped so we're in a good place with respect to global warming. Obesity is down, heart attacks are down, but cancer is through the roof. Neither Obama nor Trump could ever be elected in this world.
"You don't have to go all the way to the Oort cloud to find icy bodies"
Wait... Where are you finding enough of them now? You think a couple stray comets is going to do it?
(Score: 2) by The Shire on Sunday May 19 2019, @07:43PM (10 children)
Um, no, we don't. I think you vastly underestimate the kinds of energy that would be necessary to move planetary quantities of ice from the ORT cloud down to Mars orbit and then decelerate it enough that it doesn't instantly turn into a plasma and return to space on impact. And Mars has no magnetic field - the soil across the entire planet is saturated with percolates due to the constant bombardment by ionizing radiation from the sun. This makes it toxic to all plant life even if you brought it inside a pressurized structure. And if you were somehow to even start nudging the atmosphere into higher pressures, which you honestly can't do at that scale, it would simply be torn away again by the solar winds. Mars is completely exposed, unlike the Earth.
I stand by my analysis - this will remain the stuff of science fiction novels. The cost/benefit of trying to teraform Mars makes it more efficient to simply build a huge orbital space station. In the distant future you're far more likely to see automated mining facilities down there with maybe a small structure to house a handful of maintenance crew, but no teraforming.
0.5 psi is the equivalent of 24,000m up - that's 15 miles up. You may as well be in the vacuum of space. That doesn't help colonization AT ALL.
(Score: 2) by deimtee on Sunday May 19 2019, @11:57PM (9 children)
I did the calcs on this once, just for fun. From memory, if we ran a superconducting cable all the way round the Mars equator it would take a current of about a million amps to give Mars a magnetic field similar to Earth's. Now granted, 22,000 km of million amp superconductor is a pretty major engineering project too, but it probably isn't a bigger project than delivering all that water from the Oort cloud.
My personal preference for teraforming though would be to seed Venus with airborne modified algae to produce O2, take H2 from Jupiter, and burn it in the atmosphere to create H2O. Nine to one mass advantage over shipping water, and if you do it for long enough you start to drop the atmospheric pressure too. You need to find something to do with all that carbon too. Maybe "Diamond Spaceships for Sale Cheap !!"
If you cough while drinking cheap red wine it really cleans out your sinuses.
(Score: 2) by The Shire on Monday May 20 2019, @03:51AM (8 children)
I hope your thought experiment involved burying that cable pretty deep. I gotta believe that having it on the surface with that kind of current - well the inverse square law would seem to indicate that anyone who got anywhere near such a powerful localized magnetic field would have all the iron ripped out of their blood cells. That would be "bad".
I'm going to go out on a limb here and point out that from an orbital mechanics and pure energy requirement perspective you'd be a lot better off bringing that hydrogen in from Earth.
(Score: 2) by deimtee on Monday May 20 2019, @08:12AM (7 children)
It actually involved 50 cables at 20,000 amps each. You could spread them out, or elevate them. Remember, you're building in one third gee, putting them at the top of 200m towers wouldn't be hard. Put them 100m apart, 200m high, and designate a 10km wide strip around the equator as Atmosphere Retention Zone and Nature Park. You might not want to carry credit cards around there, but you could walk around under it no problems. Pigeons might get confused.
You don't really want to bury them, as that defeats the purpose, which is putting a magnetic field out in space. Elevating them would be the best. You could even put a ring in orbit, but I think you'll need a lot of stabilizing rockets on that. I was looking for a low maintenance option, back when it looked like we would soon have room-temp superconductors. On the other hand, if anything ever severed the orbital one you would get a truly awesome light show.
I was talking about truly heroic quantities of H2. I have no desire to dehydrate Earth. :)
Think numerous spherical tanks 1km in diameter full of liquid H2, and towed by rather large solar sails. You don't care how long it takes to get there, so you can send it on really slow gravity-assist trajectories.
If you're sceptical of that lot, you probably don't want to hear about my ideas for giving Venus a decent spin. :)
If you cough while drinking cheap red wine it really cleans out your sinuses.
(Score: 2) by The Shire on Monday May 20 2019, @03:00PM (6 children)
The problem here is that the energy required to shift something from one orbit to another is significant and directly related to both the mass you're trying to move and the relative distances between orbits. And if you are moving "heroic quantities" down towards Venus, you must also move "heroic quantities" of something else in the opposite direction. And in addition to having to overcome the orbital energy differences (there is a 50,000mph difference in orbital speeds between Jupiter and Venus), you must also escape Jupiter's intense gravitational field - no easy trick. Jupiter does not willingly let go of what it holds.
The solar wind travels in the opposite direction - you can't sail directly into the wind. And if you chose to go the ion engine route you would quickly realize there isn't enough xeon or krypton available to even approach the fuel requirements for such a venture.
In any event, you're still left with the same problem we have on Mars. Venus does not have a magnetic field to prevent the solar winds from whisking away the lighter elements like hydrogen, which is why there is essentially none in it's atmosphere. So even if you could get all that hydrogen to Venus and even if you could split the co2 and form h2o, it would still ionize in the upper atmosphere and get carried away again. The only reason Venus has a thick atmosphere at all is because it has a gravitational field close to that of earth to hold the heavier gases down. And even if you achieved all that you wanted, all you would have gained is sky city in a cloud of acid. Nothing can exist on the surface, water or not. The pressures are so great you may as well be living on the floor of the ocean sitting on top of a magma vent.
Considering the raw power and massive materials needed for such an undertaking, you would be far better off simply building an enormous space station, perhaps using a large iron asteroid as it's core.
(Score: 2) by deimtee on Monday May 20 2019, @10:28PM (5 children)
Provided you can adjust the sail faster than your orbit you can use it to break orbit. Adjust for maximum thrust when it will increase orbital speed, minimum on the other half. Regarding sailing 'into the wind', the solar wind is a minuscule effect on the sail, photon pressure is much greater [nasa.gov]. You are not going to go in a straight line line Jupiter to Venus, and by angling the reflection from the sail, you can adjust the thrust vector by up to 45 degrees. It might take a while, but if you plan far enough ahead you can use a solar sail to go anywhere in the solar system.
Obviously, if you go the ion drive route you will need to develop one that throws H+ or He+. Jupiter has plenty of both.
If you use the H2 to convert >95% of the CO2 to C and H2O, you will have enough water for small seas and a livable gas pressure at the surface. Lots of C to build with too. Did I mention long term and large quantities of H2? Actual mass quantities moved would be similar to the water to terraform Mars, but you would get a bigger, brighter planet with near normal gravity. The rate of H loss isn't really that high, if this was done it would remain habitable for millions of years.
If you cough while drinking cheap red wine it really cleans out your sinuses.
(Score: 2) by The Shire on Tuesday May 21 2019, @02:41AM (4 children)
It would literally take tens of thousands of years to deliver any hydrogen from Jupiter to Venus using solar sails that relied on 'tacking' against the wind. And you would first have to get it far away from Jupiter's gravity well or you won't be going anywhere at all.
After that, it would tack several more millennia to generate the power needed to pyrolize the co2 with the hydrogen in order to produce water and carbon. This also requires molten metals and a constant temperature of somewhere around 1,000 C for the reaction to occur at all.
And lets assume that tens of thousands of years in the future you have accomplished this incredible feat and now Venus is covered with water. Now you find yourself trying to prevent the water that faces the sun from boiling off while the water on the other side freezes since a Venutian day is around 4 Earth months long. Additionally, you still have no magnetic field so the surface is being constantly bombarded by hard radiation from the sun, much worse than standing naked in the Sahara desert in the middle of summer. It would be bad. And that's under ideal conditions.
Nah, the giganto space station is the way to go. Build your own pressurized habitable world from scratch rather than trying to fight an entire planet to be how you need it to be.
(Score: 2) by deimtee on Tuesday May 21 2019, @06:42AM (3 children)
Delta V Jupiter to Venus is somewhere around 80 - 90 km/s with no gravity assists. At 1/100,000 of a G (0.0001 m/s2) that takes 25 years. This is obviously a long term project. I am also pretty certain that by the time anyone undertook this as a project we would have ion engines that can throw any element you like. If you are in a hurry, run solar powered ion engines instead and throw away 1% at 9,000 km/s.
You don't do it that way. You seed the atmosphere with algae and let it eat the CO2 to produce O2. Then you just burn the H2.
If you cough while drinking cheap red wine it really cleans out your sinuses.
(Score: 2) by The Shire on Tuesday May 21 2019, @07:31PM (2 children)
Escape velocity from Jupiter is around 60 km/s - how exactly do you plan to get your enormous tanks of hydrogen moving at that speed? You can't just apply .0001m/s2 over extended periods of time - you won't go anywhere ever. You have to hit that 60km/s speed or you'll never leave Jupiter at all. Ion engines can never provide sufficient thrust. Ion engines aren't even capable of lifiting a 1kg mass off the moon let alone reach escape velocity on Jupiter. Your trip to Venus won't even get started if you can't escape Jupiters gravity well.
There is no such organism that could survive those conditions, with or without water. There is also no such organism that can subsist soley on sunlight and co2 and the Venutian atmosphere has none of the other things such life might require. Algae certainly does require sunlight but sunlight without a magnetic field would sterilize any organics. There is no shielding at all from the suns hard radiation.
Such fantasy is fun and makes for good books and movies. But the universe is a lot harder to tame than that.
(Score: 2) by deimtee on Friday May 24 2019, @11:28PM (1 child)
That is not how escape velocities work unless you are firing unpowered projectiles out of a gun.
Provided you start in an orbit that is high enough that your available thrust exceeds atmospheric drag, you can simply point the thust vector along your orbit and start your engine. You won't go faster, in fact you will slow down and climb into a higher orbit. That bold part is the important bit. You keep applying thrust and eventually you climb out of the gravity well. At no point do you ever need a sudden velocity change of 60km/s, that is just the sum over time of the acceleration your engine will need to apply.
Yes, you might need to supply some other trace elements. One of the main ones is going to be nitrogen compounds.
Earth's magnetic field only blocks charged particle radiation. It does absolutely nothing for UV / X-ray / gamma radiation. Yes, it's important here, but all that extra atmosphere provides shielding at least as good.
If you cough while drinking cheap red wine it really cleans out your sinuses.
(Score: 2) by The Shire on Saturday May 25 2019, @05:33PM
It absolutely IS the way escape velocities work. While it's true that a projectile with an instantaneous speed exceeding 60km/s will break free of Jupiter's influence, the fact is that no matter how slowly you accelerate, at some point you MUST reach escape velocity or all you will have achieved is an orbit.
And an ion engine can never escape Jupiter's gravity, I don't care how long it burns - duration of thrust is not the key - the power of the thruster to overcome "g" and any atmospheric resistance is the key. If you can't push forward faster than the planet is pulling you back, you're not going anywhere. You have to overcome that gravity well otherwise all you will be doing is falling at a slightly reduced speed. And that thrust has to increase proportional to the mass you're trying to move - in this case a truly enormous amount of mass indeed. Basically the only accelerating an ion engine can do in Jupiter's atmosphere is accelerating downward.
It's simply not possible with any known or even conjectured technology to do what it is you're suggesting. This kind of thinking is pure fantasy.
(Score: 2) by HiThere on Sunday May 19 2019, @11:24PM (3 children)
Have you modeled this? Some models have indicated that even Earth couldn't hold onto an atmosphere delivered that way, so they derive the current oceans from water liberated from sub-surface rocks. It makes it dubious that sending ice asteroids crashing down on Mars would yield an ocean...or even much air. The impact gets things too hot, so it all goes away.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 2) by JoeMerchant on Monday May 20 2019, @12:03PM (2 children)
Seems unlikely that a single comet strike would raise global Mars temperatures enough to be "too hot" to retain the water. Sure, dump them all in within a 28 hour period, that's too hot. One a month for 100 years?
This has me thinking, also: where does this escaped water go, and does Earth's moon act to shepherd escaped water back to the planet?
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(Score: 2) by HiThere on Monday May 20 2019, @04:12PM (1 child)
It doesn't need to be globally too hot. Locally too hot would do. All it needs to do is cause more loss than you gain, and that doesn't take much with Mars gravity. The speed of the molecules in the air is already enough to cause slow loss, and if recent reports are correct, not so slow loss whenever it warms up a bit in midsummer.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 2) by JoeMerchant on Monday May 20 2019, @07:29PM
Hard to see how an influx of mostly water, even if hot from re-entry (and, how hot can the thin Martian atmosphere really heat a massive solid comet if it is deftly dropped by calculated orbit for a minimum heat before impact re-entry?) could net strip water from an atmosphere and surface so bereft of water in the first place. Is the implication that every meteor impact is stripping volatiles from the atmosphere, even if the meteor itself is comprised of mostly volatiles?
The ground impact will be hot, stuff will boil away, sure, but, again - shouldn't amount to a net loss, and the ambient global temperature means that the cloud that expands away from the impact crater will cool as it interacts with the thin, but present, atmosphere.
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(Score: 0) by Anonymous Coward on Sunday May 19 2019, @07:18PM
uh no. You need at least 200 mbar to have a troposphere like earth, less than that is a totally different type of atmosphere at the surface.
(Score: 3, Funny) by Entropy on Sunday May 19 2019, @04:46PM (1 child)
Has caused rapid climate change(tm) and global warming(c) on Mars. This is what AOC warned us about people! We need to implement the new green plan thing immediately.
(Score: 1) by RandomFactor on Sunday May 19 2019, @08:56PM
Sounds like proof that electric vehicles are far WORSE for the environment than internal combustion ones!
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