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I'm glad Venus is getting more attention. Mars seems to get the most attention as a place to visit, but we seem to ignore Venus. Venus has a few things going f
by SaberTail 7y ago
I'm glad Venus is getting more attention. Mars seems to get the most attention as a place to visit, but we seem to ignore Venus.
Venus has a few things going for it that I think make it a better choice for permanent human habitation than Mars.
* Venus has nearly Earth-like gravity (8.9 m/s² instead of 9.8 m/s²)
* The atmosphere 50 km above the surface is the right temperature for liquid water, and has a similar atmospheric pressure to Earth at sea level. [1]
* Venus has suffered a runaway greenhouse effect. It's a good place to experiment on how to mitigate or reverse that without risking Earth. And what we do learn may be applicable to Earth in the not-too-distant future.
[1] https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20030022668.pdf https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/200300...
- modzu 7y agowell you said it: we know exactly how to heat up mars (greenhouse gases) but its not so clear how to cool down venus. also mars has water.
- hathawsh 7y agoWe don't need to cool it down. We could float a platform about 49.5 km above the surface of Venus, where the temperature and pressure nearly match the earth at sea level. To launch a probe, we could simply drop it from the platform. This article about Venus is very enlightening: https://en.wikipedia.org/wiki/Atmosphere_of_Venus https://en.wikipedia.org/wiki/Atmosphere_of_Venus
- turtlecloud 7y agoWhat if your float thing pops? Everyone sinks and dies??
- crispyporkbites 7y agoWe don't need to cool Venus down, but in a few hundred years we might need to cool the earth, so learning how to do that on Venus might be a good idea.
- modzu 7y agomy comment was in response to parent saying venus was a better candidate for colonization than mars. but i am totally on board with exploring venus, although im not convinced the atmospheric issues are significantly lesser than the surface, just different (hurricane winds, sulfuric acid, etc)
- stickydink 7y agoHow would we float a platform at that height?
- djakjxnanjak 7y agoWe can float things in the earth atmosphere at sea level. My completely ignorant prior is that we should be able to do it there too, if the temp and pressure are the same.
- ncmncm 7y agoMuch better: the air at normal pressure is much denser, so ordinary breathing air supports a balloon.
- yholio 7y agoBy attaching it to a steel balloon filled with breathing gas, which can provide lift in the Venusian atmosphere. Inside the baloon you get a really nice habitat with the correct Temperature, pressure and gas composition for humans to live in.
- aeternus 7y agoOther than a basically unlimited supply of CO2 however, what would the advantage be compared to a just a space station? With Mars, you can mine building materials from the surface.
- colordrops 7y agoYou can live there long term since there is gravity.
- Baeocystin 7y agoIs Mars' gravity too low for long-term habitation? I know that we know that zero-G is a negative, but do we have any idea if it's a threshold that needs to be reached, a linear response to G-force that scales from untenable to fine, etc?
- wuliwong 7y agoJust because you are at sea level, you can't suddenly float stuff in the air. I like your optimism though. :) I was imaging a floating city like cloud city in star wars [0]. [0] https://www.starwars.com/databank/cloud-city https://www.starwars.com/databank/cloud-city
- tfha 7y agoThis is a bit more thought out than perhaps OP applied, several theretical investigations have been done into floating cities on venus and it more or less comes down to building blimps out of gasses like nitrogen and oxygen. Because the venus atmosphere is so dense, this would actually work.
- pinewurst 7y agoVery cool NASA video: https://www.youtube.com/watch?v=0az7DEwG68A https://www.youtube.com/watch?v=0az7DEwG68A
- ryacko 7y agoHave you heard of Murphy's law? Floating above Venus provides the benefits of a gravity well, but there's the danger of sudden buoyancy loss.
- bdamm 7y agoEverything about exploring space and planets is a rebut to Murphy's law.
- sfkdjf9j3j 7y agoI wouldn't say we know exactly how to heat up Mars. Without a magnetic field, any atmosphere we conjure out of the polar regions would escape into space. We are far, far closer to completely reversing the effects of climate change on Earth than we are to teraforming Mars.
- modzu 7y agowell obviously we'd need orbiters that generate an artificial magnetic field my man! http://www.nifs.ac.jp/report/NIFS-886.pdf http://www.nifs.ac.jp/report/NIFS-886.pdf
- BurningFrog 7y agoYeah, but I believe it takes ~10 million years for a Mars atmosphere to escape. So it could be entirely feasible to treat the Mars atmosphere as a tire, that you "inflate" every now and then to keep the pressure constant.
- garmaine 7y agoThat would be a very wasteful use of precious volatiles though. But we could kick up a magnetic field with superconducting rings around the poles though.
- BurningFrog 7y agoLosing 0.00001% per year is not "very wasteful" to me. There are ideas for putting up a magnetic field based on putting a contraption in whichever L1/L2... point is between Mars and the Sun.
- garmaine 7y agoConvert that into tonnes, and then calculate how much biosphere could be supported with that volatile weight. And once it is gone, it is gone. It’s not a renewable resource. You’d be trading away billions of years of future Martian biosphere.
- jcranmer 7y agoMars' atmosphere is 95.3% carbon dioxide, which means that the problem we have to solve is not "how do we inject craptons of greenhouse gas into the atmosphere" but "how do we stop the solar wind from stripping away the atmosphere," which is not a problem we have a clear idea as to how to solve.
- JonDav 7y agoVenus has more carbon dioxide in its atmosphere and has the added bonus of the surface being pressurized like you are deep sea diving....
- aweawesome 7y agoSure but we got to survive till we could clear carbon dioxide
- HALtheWise 7y agoContrary to popular belief, the rate that solar wind strips Mars atmosphere is so ridiculously low that we can comfortably kick the problem of stopping it down the road a few hundred thousand years. If we manage to generate a habitable climate by terraforming with additional heat and atmosphere, adding a magnetic field becomes a very low priority.
- garmaine 7y agoWe do know how to cool Venus. Build a sun shade. It’s an old idea, and a simple idea, and there’s lots of engineering literature on how it can be reasonably accomplished.
- jbay808 7y agoCarl Sagan once proposed an interesting concept of terraforming Venus by floating some kind of bacteria in its atmosphere. The bacteria would be constantly drifting down to the surface and dying, but with no predators and ample resources, multiplying quickly enough to replace the losses, and small enough to be kept aloft by air currents. Gradually they would transform the carbon back into solid mass, and bring the atmospheric pressures and temperatures down to earth levels. Later on in his career he decided against that scheme, but with our progress in biotechnology, it might be the only feasible approach. https://en.m.wikipedia.org/wiki/Terraforming_of_Venus https://en.m.wikipedia.org/wiki/Terraforming_of_Venus
- mandevil 7y agoThe Soviet Union always put more attention on Venus, and the US more on Mars. From what I can tell this dates back to before there were actual space programs, so I strongly suspect this has to do with the science fiction in the respective languages. For example in H.G. Wells 1898 War of the Worlds, the bad guys are from Mars, Edgar Rice Burroghs John Carter series is about Mars, etc. whereas engineer cosmonaut Konstantin Feoktsitov wrote that when he was 10 (~1936) he came to a sad realization. Since going into space was better than everything else, any effort he put into anything other than going into space was wasted effort, BUT by the time he got the Ph.D he would need to contribute to that program men would already be on Venus, so he would never be the first to anything[1]. I don't know Russian language sci-fi well enough to guess what the source for this (or maybe was it Tsiolkovsky? dunno), but that suggests to me that the Soviet interest in Venus wasn't just because the US had a stranglehold on Mars or anything like that, it was because Venus spoke to them in the same way that Mars did to Americans. Any Russian speakers can confirm? [1]: He ended up as Sergei Korolev's right hand man, and was tasked by the Chief Designer himself with stripping all the safety devices out of the Vostok capsule so that it could hold three men [Vokshod]. When Feoktistov objected, Korolev told him if he did a good job, he'd get to take it into space, and Feoktistov accepted the challenge.
- autokad 7y agoi think the primary reason for US interest in mars is due to the fact that it is much more likely that mars #1) previously contained life and #2) we will be able to find evidence of #1 on mars, vs venus.
- garmaine 7y agoOn the other hand, NASA’s (recent!) insistence that everything be justified in terms of the search for life is not shared by everybody. I for example really don’t care at all about potential microbial life vs. extending the domain of earth’s life through permanent settlement and terraformation of both Mars and Venus.
- User23 7y agoThe cloud cover on Venus is so thick it could contain life right now. The belief that it’s necessarily barren due to extreme conditions predates the widespread knowledge of extremophile earthbound life. If you gave me better than even odds that there is life on Venus I’d take them.
- 29athrowaway 7y agoVenus is closer to Earth.
- killjoywashere 7y agoGiven a choice of death by fire and death by cold, death by cold is easier to mitigate against, and is the default problem in space. To survive Venus, you have to first survive the freezing trip to Venus. So you need heating and air conditioning. A lot. Of both. On Mars, you only need the heating systems that got you to Mars. Similar problem for radiation: going to Mars leads to less radiation. Going to Venus increases radiation. So in Venus orbit, you need more shielding than you need at low Earth orbit. On Mars, you need less. There's another commentor suggesting floating in steel balloons. Um, weather is going to be rough. Really, really rough. The mass of building materials necessary to survive the storms strikes me as likely deal-breaker. Never mind the complete lack of light. I don't know if everything is harder on Venus, but most of the first-order issues are substantially harder.
- deleted 7y ago[deleted]
- contras1970 7y ago> death by cold is [...] the default problem in space well, actually... you need lower-energy atoms for higher-energy ones to rub against to carry away the excess. there's not many atoms in vacuum, so the default problem in space is overheating. see eg. https://en.wikipedia.org/wiki/External_Active_Thermal_Control_System https://en.wikipedia.org/wiki/External_Active_Thermal_Contro... or https://en.wikipedia.org/wiki/Liquid_cooling_and_ventilation_garment https://en.wikipedia.org/wiki/Liquid_cooling_and_ventilation... > you have to first survive the freezing trip to Venus. So you need heating and air conditioning. A lot. Of both. the heating part is very, very wrong. the AC would be Atmospheric Control, see https://en.wikipedia.org/wiki/International_Space_Station#Systems https://en.wikipedia.org/wiki/International_Space_Station#Sy....
- killjoywashere 7y ago
- User23 7y agoI’m going to go out on a limb and guess that Venus’s high temperatures might be determined by solar radiation and the inverse square law and that its atmosphere is on the consequence side of the expression. That said I entirely agree we should be exploring it!
- jbay808 7y agoThat's a pretty tenuous limb to go out on. If that were the case, why is Venus hotter than Mercury, despite being farther away from the sun and having an albedo of 0.75? (Mercury's is about 0.1). In fact, with its high albedo Venus reflects so much sunlight that it absorbs even less solar energy than Earth does, but despite that, it's hotter than mercury. I am pretty sure that's all due to its atmosphere, and I think every planetary scientist would agree.
- User23 7y agoMaybe because Mercury is much smaller and thus absorbs far less solar radiation and has a far greater surface area to volume ratio allowing it to radiate heat more efficiently? Venus's atmospheric composition is a consequence of its placement relative to the sun, mass, and volume.
- jbay808 7y agoCan you explain how volume comes into play? Solar energy absorption is proportional to surface area, and radiative dissipation is also proportional to surface area. By the way, Mercury is tidally locked, with a hot side facing the sun all the time. Even that hot side is not as hot as Venus. There is no question, if you were to strip Venus' atmosphere away, it would cool down tremendously and probably be not much warmer than Earth, or even cooler depending on what albedo it ends up with. This isn't even an open question or a mystery or an active area of study, by the way. This is very solidly known. I was hoping that by pointing out well-known but surprising facts like that Mercury is colder than Venus, and Earth absorbs more sunlight than Venus, it would encourage you to question your previous standpoint. But if you want to really challenge this point, then please at least do a little more to measure the strength of the limb you are standing on. Atmospheric composition is not in general a function of mass, volume, and distance to a star, by the way. Due to feedback loops, planets can have multiple stable equilibria, and a history-dependent climate and atmosphere. That is why the concept of terraforming even makes sense. A planet with the size, mass, and location of Venus (or Earth...) can be made into a snowball or a fireball depending on albedo and greenhouse effects, and transitioned from one to the other.