15 ms·

Venus is more interesting to me than Mars. We already know more about Mars than I cared to know. Venus is still packed with mystery. Hot mystery, yes.

dmix 4y ago
It's also really interesting purely from a physics or human adventure perspective. The way it crushes anything that goes near the surface. Mars seems like an introductory class to Venus' horror story. But yes there's plenty to learn, especially from a statistical analysis for finding life in interstellar space type of thing.
- pencilguin 4y ago
  At cloud-top level, temperature, pressure, and gravity are all close to Earth-normal, and breathing-air is buoyant. Numerous materials can be extracted from the outside air, including oxygen, hydrogen, carbon, sulfur, nitrogen, and even some metals. A day/night cycle is about 100 hours, depending on how close you are to a pole. A nuclear reactor is as simple as a big fabric tube suspended vertically with a naked atomic pile hanging near the bottom, and a wind turbine turning in an opening at the top, the only moving part. You need something non-solar because nights are long. Alternatively, you can store energy with a weight on a cable attached to a generator. Play it out to discharge, winch it back up to charge. Or maybe different layers of atmosphere circulate at different rates. If so, you can hang a wind turbine in the next layer below.
  - FuriouslyAdrift 4y ago
    This is one of the plots in the Space Merchants... https://en.wikipedia.org/wiki/The_Space_Merchants https://en.wikipedia.org/wiki/The_Space_Merchants
    - dmix 4y ago
      That book any good?
      - code_biologist 4y ago
        A 3.85 avg rating with 9,862 ratings on Goodreads, so: average, but ever so slightly tilted towards good?
      - FuriouslyAdrift 4y ago
        It's older but considered one of the great classics of sci-fi.
  - aptsurdist 4y ago
    I love the mention of gravity storage here. The potential of gravity storage is very real, but you need a lot of weight and a lot of height to achieve meaningful amounts of electricity. And at large scales of weight and height it becomes a surprisingly hard problem. For example, a steel cable can’t stretch much further than a mile under earth gravity before it succumbs to its own weight. But there are other solutions. It’s not rocket science, as they say.
    - pencilguin 4y ago
      A steel cable one square inch in cross section and a mile long weighs <19k lb on Earth, a bit less on Venus. Cheap mild steel has tensile strength 50k lb/in², and can be as much as 10x as strong. So, self-supporting steel 3 miles to 30 miles. Getting 250 tons of high-strength steel cable (sheathed against corrosion) to Venus is left as an exercise for the reader. Likewise, a big enough balloon to hold that up. And a strong enough winch. But in practice, you would make the cable of carbon extracted from atmospheric CO2, instead, and it could support itself all the way down to the surface, 50 mi below. You would need to protect the end against acid vapor corrosion at 470 C: another exercise for the reader.
  - adolph 4y ago
    And the Sun rise/sets would be in the opposite direction from Earth. Imagine watching the sun setting in the East! https://astronomy.stackexchange.com/questions/26/what-is-the-current-accepted-theory-as-to-why-venus-has-a-slow-retrograde-rotati https://astronomy.stackexchange.com/questions/26/what-is-the...
    - tigerlily 4y ago
      To get a sense of it, just visit the opposite hemisphere (edit: on Earth).
      - glenngillen 4y ago
        What do you mean by that? The sun sets in the west whether you live in the northern or southern hemisphere. That said, I’m not there’s any appreciable/perceptive difference to which way the sun sets for us anyway. It’s not like we have some internal compass that naturally grounds our cardinal direction. Our only frame of reference during the day on which way is east or west is the movement on the sun. If it suddenly started going the opposite direction it’d be weird if your were experiencing it in a familiar location. If you were somewhere where you’d never experienced a sunrise or sunset before (i.e., as little as a few miles away) I suspect you’d not even notice the difference. You’d have no frame of reference to suggest anything had changed.
        wyldfire 4y ago
        > It’s not like we have some internal compass that naturally grounds our cardinal direction. I'm reminded of "Story of Your Life" [1] / "Arrival" [2] wherein a character's language shapes their thoughts. Those are fiction, but there's also some supporting non-fiction evidence. Apparently there's a tribe of humans on Earth (in Australia) whose language primarily refers to cardinal directions when describing the location of things - as in "hand me the north cup on the table". I don't think that's the only one - there's also Tenejapan Mayans [4]. From the latter group there's cited examples of an experiment with blindfolded/dizzy Tenejapan in a darkened interior who can identify the cardinal directions accurately. All of this is to say that maybe in fact some humans actually can sense this as if they had an internal compass. [1] https://en.wikipedia.org/wiki/Story_of_Your_Life https://en.wikipedia.org/wiki/Story_of_Your_Life [2] https://en.wikipedia.org/wiki/Arrival_(film) https://en.wikipedia.org/wiki/Arrival_(film) [3] https://pages.ucsd.edu/~jhaviland/Publications/ETHOSw.Diags.pdf https://pages.ucsd.edu/~jhaviland/Publications/ETHOSw.Diags.... [4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3095761/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3095761/
  - dehrmann 4y ago
    > breathing-air is buoyant I'm really curious what the temperature, atmospheric makeup, and density is at different altitudes on Venus. I had no idea there could be a theoretically habitable altitude on it.
    - pencilguin 4y ago
      Atmosphere is mostly CO2, with relatively small amounts of other stuff. O2 and N2 are lighter, so a balloon filled with them could hold stuff up.
      - dehrmann 4y ago
        So we could live in balloons?
        pencilguin 4y ago
        That is the idea. Want to go first? I will watch carefully.
        prox 4y ago
        Could be a cool game idea. Where you build in the clouds of Venus.
        zeristor 4y ago
        "You truly belong here with us among the clouds."
    - LorenPechtel 4y ago
      What's really interesting to me is that at the right latitude you can dig in and find Mercury quite habitable.
      - pencilguin 4y ago
        176 Earth days from sunrise to sunrise: 2 local years, half an Earth year. So instead of spring/ summer/fall/winter, you have day/night/day/night. At the right latitude, and a few meters deep, temperature would be comfortable. But energy would be a problem, with the season-long night. Axial tilt is <2 degrees. There might be some volatiles frozen in polar craters. Temperature at a pole would be low, but solar panels mounted vertically (or, better, a wavelength-selective mirror reflecting onto horizontal panels), rotating slowly, would offer continuous power. Constant temperature too low is a lot easier to handle than too high, or varying much. You need to dig down for protection from cosmic radiation. Gravity is about like Mars, which might or might not be adequate, long term. Nobody knows. It is remarkably hard to get to and from Mercury. Jupiter is easier.
  - yongjik 4y ago
    > At cloud-top level, temperature, pressure, and gravity are all close to Earth-normal ... ... and the cloud is made of sulfuric acid droplets. Don't breathe in, and make sure that nothing important is ever exposed to the outside air.
    - kragen 4y ago
      Maybe just coat the outside of your airship in ten microns of teflon, glass, or lead? As corrosives go, sulfuric isn't that bad.
      - pencilguin 4y ago
        Ordinary plastic is fine. You can buy concentrated H2SO4 at an auto supply store in a plastic bottle. Edit: maybe not fine. Resistance to H2SO4 corrosion falls off sharply as its concentration approaches 100%. On Venus, the clouds would be very nearly 100%.
        kragen 4y ago
        "Plastic" is lots of different things. I'd think polyethylene will be fine but not polylactide.
        pencilguin 4y ago
        I was surprised to find that carbon fiber can sit in 50% H2SO4 indefinitely, but degrades above 65%, at normal temperatures. https://www.gab-neumann.com/Corrosion-resistance-of-impervious-graphite https://www.gab-neumann.com/Corrosion-resistance-of-impervio...
        adrian_b 4y ago
        At low concentration a sulfuric acid solution corrodes only by being an acid. Neither carbon fiber is affected by acids, nor some types of plastic with carbon-carbon bonds, like polyethylene (but polyesters and other polymers made by polycondensation may be hydrolyzed by acids). At high concentrations, a sulfuric acid solution begins to have an oxidizing behavior, even if not so strong as nitric acid, so it can convert the carbon from carbon fibers or some plastics into carbon dioxide, damaging them. The difference in behavior is because the sulfate ions have a very high affinity for water. At low concentrations, they are strongly hydrated, so the attached water shields them from making direct contact with an immersed material. At high concentrations, there is much less water available for hydration and the sulfate ions can make direct contact with an immersed material. Then the oxidized sulfur atoms from the sulfate ions can oxidize any less electronegative elements.
  - rad88 4y ago
    Long-term we could plant massive new floating plant species in the atmosphere to decarbonize it and form floating soil layers, which eventually would compactify and metamorphosize and spread out latitudinally to form a ring around the planet, thinning out towards the poles and making cliffs and beaches and islands with the atmosphere. The growing regions would not actually stay together but break apart and move technically on top of the atmosphere, with plate boundaries and subduction zones and volcanoes, driven by the pressure below, surface volcanism proper, and weather around the coastal areas.
    - pencilguin 4y ago
      Keeping carbon persistently out of the atmosphere would be hard, if you are freeing oxygen. One alternative would be to make diamonds out of the extracted carbon and drop them to the ground. The released oxygen could then bind to crustal aluminum, iron, silicon, calcium, etc. Venus has sadly little hydrogen, so you won't get oceans.
      - rad88 4y ago
        Might the lighter O2 naturally rise away from the organics layer? It may then be able to oxidize metals and meteors sprayed into the upper atmosphere, eventually falling back down with those compounds to fertilize the substrate.
        pencilguin 4y ago
        Wind speed is hundreds of km/h. So, "turbulent mixing processes" rule. There is plenty of un-oxidized material on the ground. Oxygen just needs to be kept off the carbon. And, it needs stirring. Big meteors could do a bit of that. Earth gets its stirring from tectonics, which Venus lacks.
      - credit_guy 4y ago
        Just for a sense of scale, the venusian atmosphere has a mass of about half a billion GigaTons, 97% of which is CO2. Here on Earth, with all our industrial infrastructure, the substances we produce the most (iron and concrete) are in the low single digits GigaTons per year. The next ones (fertilizers and plastics) are in the hundreds of megatons per year. If you want to make a difference on Venus, you'd need to make millions of time more diamonds each year in some balloons in the skies than we make iron here on Earth.
ramraj07 4y ago
I highly recommend anyone with any interest in space follow https://youtube.com/c/MarsGuy https://youtube.com/c/MarsGuy / he gives a weekly update on what the rovers find in great detail and it’s fascinating. At the same time I continuously question if the findings they make wit these rovers continue to justify the multi billion dollar expense we make on these missions. I’d much rather we spend our limited resources on Venus and Europa, and actually starting to send interstellar probes than continuing to double down on Mars. It’s become a vanity project for billionaires anyway so let them figure out putting a man there. NASA can start focusing on the next step in exploration of space.
- dmix 4y ago
  > It’s become a vanity project for billionaires anyway so let them figure out putting a man there. That is one prominent billionaire's idea for stuff to do in the next decade yes... But he wasn't a major factor considered by NASA when the current projects were funded. Otherwise I'd probably agree Mars might have gotten too much federal funding vs other projects in the last decade.
  - pencilguin 4y ago
    I, for one, am eager to see any random billionaire go to Mars, provided they stay. I would bet any amount of money none will.
wallfacer120 4y ago
There's no mystery to Mars, just letting its crust hang out there for all to see.
- Pigalowda 4y ago
  I agree. It’s quite scandalous.
dr_dshiv 4y ago
The moon is more interesting than either. Focus on asteroid belts. Big gravity wells suck.
- newZWhoDis 4y ago
  It’s not sexy but it’s true. Asteroid mining will completely change life on earth. Imagine the technical implications of copper, gold, platinum, etc becoming as cheap and abundant as tin foil.
  - Moissanite 4y ago
    I imagine the most efficient option will be to either crash the asteroids into the Earth directly (assuming they aren't too big), or "land" them on the moon for exploitation there. Sending a whole mining/refining rig to each asteroid feels a bit too high risk.
    - dr_dshiv 4y ago
      Disagree. You can just electromagnetic mass drive the finished good back to earth orbit for collection.
      - pencilguin 4y ago
        Right. The bottom of a gravity well is a nuisance for anything other than human survival.
      - Moissanite 4y ago
        You can't "just" do anything. Landing a significant payload on an asteroid is barely do-able right now. We are a long way from building mining rigs and railguns up there; clamping on an engine and some extra propellant is much more viable in the near term - generously estimated at within the next 30 years.
        Nomentatus 4y ago

dmix 4y ago

It's also really interesting purely from a physics or human adventure perspective. The way it crushes anything that goes near the surface. Mars seems like an introductory class to Venus' horror story. But yes there's plenty to learn, especially from a statistical analysis for finding life in interstellar space type of thing.

pencilguin 4y ago
At cloud-top level, temperature, pressure, and gravity are all close to Earth-normal, and breathing-air is buoyant. Numerous materials can be extracted from the outside air, including oxygen, hydrogen, carbon, sulfur, nitrogen, and even some metals. A day/night cycle is about 100 hours, depending on how close you are to a pole. A nuclear reactor is as simple as a big fabric tube suspended vertically with a naked atomic pile hanging near the bottom, and a wind turbine turning in an opening at the top, the only moving part. You need something non-solar because nights are long. Alternatively, you can store energy with a weight on a cable attached to a generator. Play it out to discharge, winch it back up to charge. Or maybe different layers of atmosphere circulate at different rates. If so, you can hang a wind turbine in the next layer below.
- FuriouslyAdrift 4y ago
  This is one of the plots in the Space Merchants... https://en.wikipedia.org/wiki/The_Space_Merchants https://en.wikipedia.org/wiki/The_Space_Merchants
  - dmix 4y ago
    That book any good?
    - code_biologist 4y ago
      A 3.85 avg rating with 9,862 ratings on Goodreads, so: average, but ever so slightly tilted towards good?
    - FuriouslyAdrift 4y ago
      It's older but considered one of the great classics of sci-fi.
- aptsurdist 4y ago
  I love the mention of gravity storage here. The potential of gravity storage is very real, but you need a lot of weight and a lot of height to achieve meaningful amounts of electricity. And at large scales of weight and height it becomes a surprisingly hard problem. For example, a steel cable can’t stretch much further than a mile under earth gravity before it succumbs to its own weight. But there are other solutions. It’s not rocket science, as they say.
  - pencilguin 4y ago
    A steel cable one square inch in cross section and a mile long weighs <19k lb on Earth, a bit less on Venus. Cheap mild steel has tensile strength 50k lb/in², and can be as much as 10x as strong. So, self-supporting steel 3 miles to 30 miles. Getting 250 tons of high-strength steel cable (sheathed against corrosion) to Venus is left as an exercise for the reader. Likewise, a big enough balloon to hold that up. And a strong enough winch. But in practice, you would make the cable of carbon extracted from atmospheric CO2, instead, and it could support itself all the way down to the surface, 50 mi below. You would need to protect the end against acid vapor corrosion at 470 C: another exercise for the reader.
- adolph 4y ago
  And the Sun rise/sets would be in the opposite direction from Earth. Imagine watching the sun setting in the East! https://astronomy.stackexchange.com/questions/26/what-is-the-current-accepted-theory-as-to-why-venus-has-a-slow-retrograde-rotati https://astronomy.stackexchange.com/questions/26/what-is-the...
  - tigerlily 4y ago
    To get a sense of it, just visit the opposite hemisphere (edit: on Earth).
    - glenngillen 4y ago
      What do you mean by that? The sun sets in the west whether you live in the northern or southern hemisphere. That said, I’m not there’s any appreciable/perceptive difference to which way the sun sets for us anyway. It’s not like we have some internal compass that naturally grounds our cardinal direction. Our only frame of reference during the day on which way is east or west is the movement on the sun. If it suddenly started going the opposite direction it’d be weird if your were experiencing it in a familiar location. If you were somewhere where you’d never experienced a sunrise or sunset before (i.e., as little as a few miles away) I suspect you’d not even notice the difference. You’d have no frame of reference to suggest anything had changed.
      - wyldfire 4y ago
        > It’s not like we have some internal compass that naturally grounds our cardinal direction. I'm reminded of "Story of Your Life" [1] / "Arrival" [2] wherein a character's language shapes their thoughts. Those are fiction, but there's also some supporting non-fiction evidence. Apparently there's a tribe of humans on Earth (in Australia) whose language primarily refers to cardinal directions when describing the location of things - as in "hand me the north cup on the table". I don't think that's the only one - there's also Tenejapan Mayans [4]. From the latter group there's cited examples of an experiment with blindfolded/dizzy Tenejapan in a darkened interior who can identify the cardinal directions accurately. All of this is to say that maybe in fact some humans actually can sense this as if they had an internal compass. [1] https://en.wikipedia.org/wiki/Story_of_Your_Life https://en.wikipedia.org/wiki/Story_of_Your_Life [2] https://en.wikipedia.org/wiki/Arrival_(film) https://en.wikipedia.org/wiki/Arrival_(film) [3] https://pages.ucsd.edu/~jhaviland/Publications/ETHOSw.Diags.pdf https://pages.ucsd.edu/~jhaviland/Publications/ETHOSw.Diags.... [4] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3095761/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3095761/
- dehrmann 4y ago
  > breathing-air is buoyant I'm really curious what the temperature, atmospheric makeup, and density is at different altitudes on Venus. I had no idea there could be a theoretically habitable altitude on it.
  - pencilguin 4y ago
    Atmosphere is mostly CO2, with relatively small amounts of other stuff. O2 and N2 are lighter, so a balloon filled with them could hold stuff up.
    - dehrmann 4y ago
      So we could live in balloons?
      - pencilguin 4y ago
        That is the idea. Want to go first? I will watch carefully.
        prox 4y ago
        Could be a cool game idea. Where you build in the clouds of Venus.
        zeristor 4y ago
        "You truly belong here with us among the clouds."
  - LorenPechtel 4y ago
    What's really interesting to me is that at the right latitude you can dig in and find Mercury quite habitable.
    - pencilguin 4y ago
      176 Earth days from sunrise to sunrise: 2 local years, half an Earth year. So instead of spring/ summer/fall/winter, you have day/night/day/night. At the right latitude, and a few meters deep, temperature would be comfortable. But energy would be a problem, with the season-long night. Axial tilt is <2 degrees. There might be some volatiles frozen in polar craters. Temperature at a pole would be low, but solar panels mounted vertically (or, better, a wavelength-selective mirror reflecting onto horizontal panels), rotating slowly, would offer continuous power. Constant temperature too low is a lot easier to handle than too high, or varying much. You need to dig down for protection from cosmic radiation. Gravity is about like Mars, which might or might not be adequate, long term. Nobody knows. It is remarkably hard to get to and from Mercury. Jupiter is easier.
- yongjik 4y ago
  > At cloud-top level, temperature, pressure, and gravity are all close to Earth-normal ... ... and the cloud is made of sulfuric acid droplets. Don't breathe in, and make sure that nothing important is ever exposed to the outside air.
  - kragen 4y ago
    Maybe just coat the outside of your airship in ten microns of teflon, glass, or lead? As corrosives go, sulfuric isn't that bad.
    - pencilguin 4y ago
      Ordinary plastic is fine. You can buy concentrated H2SO4 at an auto supply store in a plastic bottle. Edit: maybe not fine. Resistance to H2SO4 corrosion falls off sharply as its concentration approaches 100%. On Venus, the clouds would be very nearly 100%.
      - kragen 4y ago
        "Plastic" is lots of different things. I'd think polyethylene will be fine but not polylactide.
        pencilguin 4y ago
        I was surprised to find that carbon fiber can sit in 50% H2SO4 indefinitely, but degrades above 65%, at normal temperatures. https://www.gab-neumann.com/Corrosion-resistance-of-impervious-graphite https://www.gab-neumann.com/Corrosion-resistance-of-impervio...
        adrian_b 4y ago
        At low concentration a sulfuric acid solution corrodes only by being an acid. Neither carbon fiber is affected by acids, nor some types of plastic with carbon-carbon bonds, like polyethylene (but polyesters and other polymers made by polycondensation may be hydrolyzed by acids). At high concentrations, a sulfuric acid solution begins to have an oxidizing behavior, even if not so strong as nitric acid, so it can convert the carbon from carbon fibers or some plastics into carbon dioxide, damaging them. The difference in behavior is because the sulfate ions have a very high affinity for water. At low concentrations, they are strongly hydrated, so the attached water shields them from making direct contact with an immersed material. At high concentrations, there is much less water available for hydration and the sulfate ions can make direct contact with an immersed material. Then the oxidized sulfur atoms from the sulfate ions can oxidize any less electronegative elements.
- rad88 4y ago
  Long-term we could plant massive new floating plant species in the atmosphere to decarbonize it and form floating soil layers, which eventually would compactify and metamorphosize and spread out latitudinally to form a ring around the planet, thinning out towards the poles and making cliffs and beaches and islands with the atmosphere. The growing regions would not actually stay together but break apart and move technically on top of the atmosphere, with plate boundaries and subduction zones and volcanoes, driven by the pressure below, surface volcanism proper, and weather around the coastal areas.
  - pencilguin 4y ago
    Keeping carbon persistently out of the atmosphere would be hard, if you are freeing oxygen. One alternative would be to make diamonds out of the extracted carbon and drop them to the ground. The released oxygen could then bind to crustal aluminum, iron, silicon, calcium, etc. Venus has sadly little hydrogen, so you won't get oceans.
    - rad88 4y ago
      Might the lighter O2 naturally rise away from the organics layer? It may then be able to oxidize metals and meteors sprayed into the upper atmosphere, eventually falling back down with those compounds to fertilize the substrate.
      - pencilguin 4y ago
        Wind speed is hundreds of km/h. So, "turbulent mixing processes" rule. There is plenty of un-oxidized material on the ground. Oxygen just needs to be kept off the carbon. And, it needs stirring. Big meteors could do a bit of that. Earth gets its stirring from tectonics, which Venus lacks.
    - credit_guy 4y ago
      Just for a sense of scale, the venusian atmosphere has a mass of about half a billion GigaTons, 97% of which is CO2. Here on Earth, with all our industrial infrastructure, the substances we produce the most (iron and concrete) are in the low single digits GigaTons per year. The next ones (fertilizers and plastics) are in the hundreds of megatons per year. If you want to make a difference on Venus, you'd need to make millions of time more diamonds each year in some balloons in the skies than we make iron here on Earth.

ramraj07 4y ago

I highly recommend anyone with any interest in space follow https://youtube.com/c/MarsGuy https://youtube.com/c/MarsGuy / he gives a weekly update on what the rovers find in great detail and it’s fascinating. At the same time I continuously question if the findings they make wit these rovers continue to justify the multi billion dollar expense we make on these missions. I’d much rather we spend our limited resources on Venus and Europa, and actually starting to send interstellar probes than continuing to double down on Mars. It’s become a vanity project for billionaires anyway so let them figure out putting a man there. NASA can start focusing on the next step in exploration of space.

dmix 4y ago
> It’s become a vanity project for billionaires anyway so let them figure out putting a man there. That is one prominent billionaire's idea for stuff to do in the next decade yes... But he wasn't a major factor considered by NASA when the current projects were funded. Otherwise I'd probably agree Mars might have gotten too much federal funding vs other projects in the last decade.
- pencilguin 4y ago
  I, for one, am eager to see any random billionaire go to Mars, provided they stay. I would bet any amount of money none will.

wallfacer120 4y ago

There's no mystery to Mars, just letting its crust hang out there for all to see.

Pigalowda 4y ago
I agree. It’s quite scandalous.

dr_dshiv 4y ago

The moon is more interesting than either. Focus on asteroid belts. Big gravity wells suck.

newZWhoDis 4y ago
It’s not sexy but it’s true. Asteroid mining will completely change life on earth. Imagine the technical implications of copper, gold, platinum, etc becoming as cheap and abundant as tin foil.
- Moissanite 4y ago
  I imagine the most efficient option will be to either crash the asteroids into the Earth directly (assuming they aren't too big), or "land" them on the moon for exploitation there. Sending a whole mining/refining rig to each asteroid feels a bit too high risk.
  - dr_dshiv 4y ago
    Disagree. You can just electromagnetic mass drive the finished good back to earth orbit for collection.
    - pencilguin 4y ago
      Right. The bottom of a gravity well is a nuisance for anything other than human survival.
    - Moissanite 4y ago
      You can't "just" do anything. Landing a significant payload on an asteroid is barely do-able right now. We are a long way from building mining rigs and railguns up there; clamping on an engine and some extra propellant is much more viable in the near term - generously estimated at within the next 30 years.
      - Nomentatus 4y ago