AGU Day 2: Venus

Poor Venus. Even though it is right next door to Earth, it tends not to get much attention. This is because it’s so hot that we can’t last long if we land there, and it’s so cloudy that we can’t study its surface very easily from orbit. It’s a really interesting place though: it is the closest planet in size to the Earth, but it’s climate is drastically different. NASA has quietly begun looking at what it would take to send a flagship mission to Venus, and so the first couple of talks this morning considered what we know about Venus and what the remaining big questions are.


Jim Head gave a whirlwind tour of what we know about Venus. He especially emphasized that the best way to study Venus is in terms of comparative planetology. In other words, how and why is Venus similar to the other planets and how/why is it different? One of the very strange things about Venus is that, unlike Mars and Mercury and the Moon, its surface is not very old. There are some craters, but most of the planet is volcanic plains and tectonic ridges. On the other hand, it doesn’t seem to have active plate tectonics like the earth. Venus seems to be a third, unique case. Its craters are completely randomly distributed. There is no place on Venus that clearly has a higher or lower concentration of impact. This means that the whole surface is about the same age and may imply that it underwent “catastrophic resurfacing”. Obviously, it would be nice to know how such a process works and whether it could happen to earth…

Ellen Stofan gave a good introduction to the Venus Exploration Advisory Group’s (VEXAG’s) list of outstanding questions for Venus exploration. The questions are:

  • Did Venus ever have an ocean?
  • Was its atmosphere ever earthlike?
  • Why does it rotate so slow? (Venus rotates once every 243 days)
  • Why does its atmosphere rotate so fast? (The winds on Venus circulate around the planet about 60 times as fast as the solid planet spins)
  • What caused Venus’s resurfacing, and what was its relation to climate change?
  • Was Venus ever habitable?


This morning I also heard about Japan’s upcoming “Planet-C” Venus Climate Orbiter, which is set to launch in 2010 and will have a nominal mission of 2 years in orbit around Venus. The orbiter will carry 5 cameras to look at Venus in UV, visible, near-infrared and long-wave-infrared. Its main focus is atmospheric dynamics, but will also provide information about lightning, cloud physics, and potential active volcanoes. It will be in an elliptical orbit so that at the farthest point from the planet its orbit will be synchronous with the rotation of the atmosphere.

The final Venus talk of the morning was by Dave Senske about NASA’s study of doing a flagship mission to Venus in the 2020-2025 timeframe. The mission that he described was very ambitious: it would involve two launches! The first would deliver an orbiter and the second would follow with 2 balloons and 2 landers. The balloons would float between 50 and 70 km high in the atmosphere and would last at least a few weeks. The landers would go all the way to the hot, high-pressure surface and would be designed to last at least 5 hours, although Senske mentioned that obviously it would be nice if they lasted for days or months.

A Venus balloon prototype.

A Venus balloon prototype.

The biggest obstacle to landing things on Venus is that we just don’t have technology that can handle the extreme temperatures and pressures. Senske said that their mission concept is pretty conservative in terms of new technology needed, but I still suspect that there will be a lot of difficult problems to overcome to succeed. Of course, this is the sort of thing that NASA engineers love to do, and I bet a lot of the technology needed for a Venus mission would have applications here on Earth.

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63 Comments on “AGU Day 2: Venus”

  1. changcho Says:

    A Venus rover would be nice…a Venus rover that lasts more than a nanosecond, that is.

  2. kurt9 Says:

    Maybe the lack of plate tectonics on Venus is the reason for a periodic “catastrophic resurfacing” events that Venus experiences. Plate tectonics allows for a regulated release (volcanos and earthquakes) of the heat and pressure build-up within a planet. Without plate tectonics, this heat and pressure builds up over millions of years until it breaks through the surface all over the planet, thus making Venus the “venus-like” hell-hole it is. If this is true, then we don’t have to worry about this on Earth because we have plate tectonics.

    This scenario could explain certain features of Mars such as the Tharsis bulge and the lack of craters in the Northern hemisphere. Mars may have had plate tectonics, but since it is a smaller planet lacking a large moon, these stopped after, say, the first billion years. Later, Mars may have had a partial resurfacing event (the northern hemisphere), followed by an aborted partial resurfacing event (the Tharsis bulge) that was aborted because the planet no longer had enough internal heat to make it happen.

    This all has implications with regards to the presence of “Earth-like” worlds throughout the galaxy. If plate tectonics is necessary for “Earth-like” conditions (that is, without them you get Venus-like conditions) and the large moon is necessary to initiate and maintain those plate tectonics, then it is likely that “Earth-like” planets are quite rare. In this case, there are many “Venus-like” planets but not so many “Earth-like” ones. This, of course, provides a good explanation for Fermi’s paradox.

    • Ryan Says:

      You’re right on Kurt, many scientists have suggested a link between the lack of plate tectonics and Venus’s resurfacing. And you’re right that if plate tectonics are required for life, then life is likely less common. There is the question, though, of why Earth has active plates while Venus doesn’t. What caused the difference in our evolution?

  3. Eric SECT Says:

    I’d like to see, as part of this flagship mission, an atmospheric multiple sample return mission. There are thick, stable, global layers in the clouds where temperatures and pressures are Earth-like (but highly acidic and with very low moisture).

  4. kurt9 Says:

    Hello Ryan,

    Maybe the Giant Impact that made our moon was necessary to initiate plate tectonics and that the increased tidal stresses resulting from the presence of such a moon is necessary to maintain plate tectonics over the billions of years. The tidal stresses from both the Moon and Sun are about double of that from the Sun alone. Also, the stresses change with the revolution of the Moon. I think our Moon is a factor in this.

    Mars might be a test of this. If Mars did have plate tectonics in the past, then a large moon is not necessary to make them. If not, it does suggest that a large Moon is necessary here.

  5. stan Says:

    Don’t you think they could send a sound wave into the atmosphere of the planet and when it comes back we could transfer the sounds so that we could “see” the crust without actually seeing the crust?

  6. Ryan Says:

    Stan: sound waves wouldn’t work because they can’t travel through empty space, but what you’re describing is exactly what we do with radar! The view of Venus at the beginning of the post was made by sending radar waves through the clouds, where they bounce off of the rocky surface and are received by a spacecraft. Depending upon how good the surface is at reflecting radar waves, you get different brightnesses. Typically, rough terrain scatters the radar back to the spacecraft and appears “bright” while smooth terrain reflects the radar away and appears “dark”.

  7. cheska Says:

    say it directly …what’s in venus

  8. michelle Says:

    this is helpful to others

  9. Ryan Says:

    Cheska: What’s in Venus? Rocks and metal.

    Michelle: I’m glad you found this helpful!

  10. Holly Says:

    Are these pictures copyright?

  11. Ryan Says:

    Holly: I found them online with a Google search, so I think they should be free to use however you like. The Venus and the balloon picture are NASA’s and the middle one is from the JAXA site for the Planet-C probe.

  12. angela Says:

    i need some pics sent to me on the planets think you can do that for me its for a science fair project!

  13. Ryan Says:

    Check this site for all of NASA’s planet pictures:

  14. paige Says:

    i wish yal had the size of the planet venus we need more info

  15. Ryan Says:

    Google it. I’m sure Wikipedia will have more than enough info.

  16. Rob Says:

    I think the theory of a moon necessary for tectonics to take place is very possible. A former member of the USGS is predicting earth quakes based on cycles of the moon and tidal movements. His theory is that even ground water is affected by the moon and this underground water moving acts as lubricant along with the gravitational pull of the moon. If tectonic plate action is accentuated by the moon, could it help the core of our planet remain molten? It is theorized that Mars does not have a molten core anymore and thereby can’t have protection from the sun’s rays. I wonder if Mars had a large moon if its core would have remained molten like the Earths.

  17. Ryan Says:

    Rob, there was actually a recent paper suggesting that Mars used to have several medium-sized moons that maintained its molten core (and therefore magnetic field and atmosphere), but that they gradually spiraled in and crashed into the planet, forming the largest of the ancient impact basins. Pretty interesting stuff!

  18. Rob Says:

    I would be interested to see more on the core of Venus. It must be molten given the high temp of the surface of 860 F. If there is sufficient iron then it must generate a magnetosphere which should shield the planet from some of the harmful UV radiation even if the CO2 atmosphere holds in the heat. It is interesting to note that Mercury is half the distance to the sun has a surface temp that runs the gambit from -300F at night to over 600F in the daytime. If not for the runaway greenhouse effect the planet should be able to maintain temps that would make it hospitable to life. Several ideas of terra forming Mars never seem to extend to ideas of terra forming Venus. It would seem to me to take less effort to terra form Venus. I also wonder if the reversed rotation to the sun of Venus might also contribute to its high surface temp and the fact that its surface rotates about 2 revolutions per its solar orbit. Does our planet enjoy more global cooling because of its faster rotation and the surface being exposed more often to night?

  19. Ryan Says:

    The problem with Venus is that it lacks rapid rotation to power a magnetic field. I agree that terraforming Venus is often overlooked. The problem is that Venus is as dry as a bone, so even if we could cool it off, it would just be a big desert. Mars at least has some ice underground.

    I don’t think the rotation has much effect; Venus has pretty much the same surface temp at night as during the day. It’s true that the earth would go through much larger swings in temperature if it rotated slower, but the surface of Venus is hot because of the greenhouse effect, and that’s just as potent at night.

  20. Rob Says:

    Good points on the rotation being too slow and the lack of water. This would make it a very expensive proposition to have just a stop off on the way the sun! Hardly seems worth the effort of even thinking of it. I wonder if life ever evolved there and if so to what extent. Has there ever been a probe to have survived landing on the surface? As I understand it the present mission would be the first.

  21. Rob Says:

    Looking at the title, The Martian Chronicles, I was wondering if there is a similar subject like this one concerning Mars?

  22. Ryan Says:

    Yes, the Russian Venera probes survived long enough on the surface to take a few pictures and do some basic studies of the rock composition.

    I don’t think I’ve done a post about terraforming Mars… maybe I’ll have to fix that. :)

  23. jake Says:

    how long would terraforming take?

    • Ryan Says:

      Terraforming would likely take many thousands of years for either Mars or Venus to reach a stable Earth-like climate if that is even possible.

  24. Rob Says:

    I have an idea for terra forming that use small nukes dropped in the polar ice caps and introduce algaes. The nukes would put dust and moisture in the atmosphere and start a green house effect. The algaes some of which can grow in extreme environments would grow and start the process of oxegen. If we started now by the time we get there in 20 years it might be enough of a start to begin growing other things. Of course this would never be allowed because it would be the begining of weaponizing space and possibly destroying any life there now. My guess is even if we went extreme it would take 100 years before you could breath without a device.

    • Ryan Says:

      It is likely not that simple. Planets are very complex systems, and their responses to perturbations may not be what we expect. For example, if you vaporized the ice caps on Mars, they would likely just snow back out at the poles over the next few decades. What’s more, they would probably snow over a much larger area of the surface than the ice caps currently cover (picture taking all that ice and spreading it thin over the whole arctic and antarctic areas), thus increasing the planet’s ability to reflect sunlight, which might end up cooling the planet down.

      I suspect that you would have to pump lots of water vapor and CO2 into the martian atmosphere, but also other more powerful greenhouse gases like methane or CFCs.

      Also, I doubt that the entire world’s nuclear arsenal would be able to vaporize the Martian polar caps. The martian polar caps are millions of cubic kilometers of ice. That’s a lot to vaporize! Better bet would be to redirect a passing meteor or comet to hit the polar cap.

  25. jake Says:

    Also the water would be extremly heavy,to carry from earth to space, and now days we dont have enuff gas to even try.
    But didnt scientest discover an ancient algae in alaska(some place icey) that can grow extreamly fast? what if we some how we put that on a planet, to terraform? (I think that it grew in a few days.)

    • Ryan Says:

      Mars has some water buried underground that could be released. But you’re right, bringing water from earth wouldn’t make much sense. There’s tons of ice in the outer solar system though. Comets are probably the best bet.

      I doubt Alaskan algae would survive for long on Mars. Mars is far colder than Antarctica most of the time. In the winter, the CO2 in the atmosphere freezes solid! The algae would have to be engineered to survive in extremely cold and dry environments.

  26. Rob Says:

    I believe that as our own ice caps melt they are releasing trapped Co2 in the ice. It is likely there is some in that ice as well. Would a better plan be to steer comets [icey snowballs] towards the planet and impact the surface with them? Or would that cause more dimming than a greenhouse effect? It may be overstated as well as to the cause of our own global warming and its causes.

    • jake Says:

      But the whole point of terriforming is to do the green house effect to make it wormer. Like our planet is warm enuff.
      So maybe we should burn gas, or plastic!!!!

    • Ryan Says:

      Yeah, the Martian caps are mostly water but also have a seasonal CO2 blanket. It’s difficult to tell what the effect of a comet would be. It’s a lot of ice, but not much compared to the polar caps. But on the other hand, it’s a lot of energy that would be deposited in the planet system. Clearly this is an experiment that we should try! :)

  27. nicole Says:

    you guy rock lol

  28. jake Says:

    Okay a Comet would be a good idea dont get me wrong. but that sounds major
    SCIFI, how would you even begin to direct a comet in that direction? we have enuff
    problems geting up there in the first place!!!!

  29. Rob Says:

    Current plans for moving asteroids that might impact that planet don’t seem that far fetched. One is to park a large satellite next to the object when it is really far out. The gravitation pull however slight will be lots after it travels a few millon miles. Another is to land on the surface by robot. Anchor itself in, fire long cables out with weights on the ends and keep them spinning at thier ends. Large rolls of sheeting is deployed down them. Photons and other light particle impact these and push ever so slightly on the object moving it into a different orbit or flight path in space. It is hard to grasp the concept that light is a particle but it might be enough to do that large of a job. Ryan, do you really think the comet idea has merit? I always have been then so many of my good ideas have been shot down when someone points out the obvious.

    • Ryan Says:

      I think altering the trajectory of a comet could certainly be done. Whether it would do much in the way of terraforming is much less certain. There would have to be a lot of climate modeling done to have a good idea of how the planet system would respond to a comet impact.

      Keep in mind that Mars has been hit with hundreds and thousands of comets since it became cold and dry, and it remains cold and dry.

  30. Rob Says:

    Comets or asteroids? What is the true definition of each and what is the major diffence? I have always thought of comets much larger and on some sort of orbital path.

    • Ryan Says:

      Ideally, a comet should be icy with a plume of gas (due to sublimation of the ice by the sun) and an asteroid should be rocky. In practice it’s not so easy, since most of them are just specks of light in a telescope photo. There have been “asteroids” that suddenly sprouted tails of gas like comets, and comets that ran out of volatiles and ended up as burnt-out “asteroids” of nonvolatile stuff.

  31. jake Says:

    okay, very good points! but the time it would take to try and terraform, and move the comet would take alot of time! plus like you said Ryan it would take time to find the righ comet with the righ kind of gas(or do all comets have the same gas?). so like i said why dont we try to worm it by exposing the planet with the same cimiculs we expose earth to every day, to warm it up?

    • Ryan Says:

      Comets are all roughly the same composition: mostly water ice, some other ices, and some rocky stuff.

      I think it’s still a lot easier to steer a comet to hit a planet than it is to launch a pollution factory to another planet. Remember, if that factory is going to be spitting out high-efficiency greenhouse gases, it needs to make them out of something, so it will either need to be very advanced and able to harvest the materials from the planet, or it will have to have huge tanks of chemicals, which will be extremely difficult to launch and land on another planet.

  32. jake Says:

    okay, good point!

  33. Venus is a Parralel Earth and the Earth of my origin.
    But I know it as Earth and we call your Earth that I am currently visiting Venus, its kind of reversed.
    Two identicle Planets seperated by a dimension.

    There are diferences though.
    Dont be surprised Parralel Earth Planets can be found througout the cosmos.
    Cloaking Veil Technology is widely used by advanced civilizations, explaining cloud cover on Venus and the desert effect on Mars etc etc etc.

    For more info your welcome to study some of my research.
    Yours cincerely

    hope this helps you as alternative research

    • mr.captin peter i am new to this thing and i was wondering if you have any information on how venus rotates………i have a science project coming up and i am doing it on venus so please if you chould tell me about venus…..i am only in the 6th grade and i really need information?!!!!!!!!

  34. jake Says:

    wow, someones lost it!!!! HaHa, prove it!!!!!! what a loser if you have nothing better to do then say your an alien!!!!!!

    • Ryan Says:

      Now now, be nice to our extraterrestrial visitor. Maybe he has some insight into our discussion of terraforming…? Maybe not.

  35. Rob Says:

    I have often thought the cloud cover over Venus would be an excellent way to hide a burgeoning society. Reminds me of a Twilight zone episode where aliens on Mars put a research Lander inside a museum that they thought was what earth once looked like, barren with too much water and carbon to support the silicon based life forms that they were. Meanwhile the probe was busy sending signals back to earth from their display.

  36. jake Says:

    Okay fine, i will say the possibilty of life on other planets is a possibilty, there are 180 million out of 100,000,000 planetary bodies that could possibly exist in our solar system, then there are 18,000 out of the 180 million left that could have life.
    So yes there is the possibilty that there could be life some where else, but do not come out of no where saying that life exist right next door with no plasuable proof of life!!!!!!

  37. Hi Jake,
    Im not offended beleiev me.
    Just sharing with everybody something diferent.
    But if you ever by any chance feel a slight throbing sensation around the Heart area while your conciouse and awake.
    That means youve just been transported interdimensionally or through Time.
    Apart from that everything else will probably look the same and feel the same if your end up on an Earth Planet

    Peace everyone

  38. jake Says:

    again nothing but SCIFI crap! you have no proof!!!!

  39. jake Says:

    lol, okay i just cant not stand that crap! any ways. terraforming! who long and what kind of experamentation would have to take place, before making any form of progress? i say it would take an extremly long time, then we would still have to wait even longer form the planet to worm up!

  40. Rob Says:

    Worse than the time it would take to actually do it. With all the environmental concerns and impact studies it is likely to never happen as it would be in endless debates as to whether it would destroy the existing life or damage it, ie microbes and viruses! How about the damage to the land itself? If people can be worried about wasteland like Anwar Alaska. Then if they could actually decide to do it then religion is likely to kick in and “Only God can create life”. I am positive the Pope would eventually agree to this but only after some debate. Now the biggie, what kinds of permits will it take? Some government will claim domain and want a fortune to allow it. After all of that, who will own it?

    • Rakesh Says:

      Nice discussion guys.
      Instead of directing a comet to Mars, I guess Venus would be a better bet. Venus is hot and has no water. So a comet will help it cooldown and add water to it. Once it absorbs water it can act as lubricant for plate tectonics and might kickstart one with little help from Sun’s gravity. I am wondering if it would even increase the rotational speed of Venus??? If all these could happen on Venus, it will become second Earth…
      Correct me if I am wrong.

      • Ryan Says:

        I think your main flaw is in saying that the comet would cool Venus down. Water is a greenhouse gas (in fact a stronger one than CO2) and a comet would impact with a lot of energy, so I would think comets would heat Venus up.

        You’re right though that cooling a planet is probably easier than warming one. We would just need to block some fraction of the sunlight that Venus receives.

        I doubt any of this would change the rotational speed of the planet.

      • Rakesh Says:

        I was thinking like, if there is more water vapour in atmosphere it helps in forming clouds and rains(most likly acid rains in Venus) This might reduce water vapour, sulphur and CO2 in atmosphere? (maybe we can use some chemicals to harvest clouds?)
        If there is already enough water vapour in Venus then we can just try to start cycle of rain…

        just a wild though.. does it make any sense?

        Can you explain why atmosphere in Venus rotates faster than the planet itself?

      • Ryan Says:

        The problem is that even if you formed rainclouds on Venus, the water would never leave the atmosphere, because the rain would vaporize long before hitting the surface. So water is just going to act as a greenhouse gas. You need to cool the planet down before any other terraforming steps can take place. Right now the planet is so hot that carbonate rocks can’t even form! It is estimated that Earth and Venus have similar amounts of CO2, but Earth’s is all trapped in carbonates.

        As for Venus’s superrotating atmosphere, I don’t think anyone really understands that. There are some theories, but I am not very qualified to explain them.

  41. jake Says:

    This is off topic, sorry, but i think it woulb be very binafitual if we took all the crap we put into space, (space junk) and just shot it into to sun. Or maybe that coulb play as the comet you speak of! I dont knoow, the space junk worrys me.

    • Ryan Says:

      You are right that space junk is a big problem. But there are some flaws with your idea. First: how do we collect all the space junk? and second: it actually takes more energy to launch things into the sun than it does to launch them out of the solar system! This is because to send something into the sun, you have to counteract the earth’s orbital velocity, but to launch something away that velocity works to your advantage.

  42. Rob Says:

    Nasa is currently tracking over 13,000 pieces of junk larger than 4 inches right now most of which is supposed to maintain low earth orbit past 2025. Last year the Chinese in an effort to scare the rest of the world with thier space savey used one of their satellites to impact another one creating a larger mess. Now they are suggesting on cleaning it all up. My question is how could that possibly be done? Some of these thing like a dropped wrench is traveling at 15,000 mph. Maybe we need some UAVs to fly around and zap them like in an Asteroids game? If you could some how do it I would think that the setup in tracking etc would likly take a day for each chunk.

  43. kaori Says:

    muito loko isso as imagens intão

  44. Kaitlynn M. Says:

    I love your pictures and the baloon is very big. Imagine that in your house in each room. How would you get around that plac?

  45. hi everyone my name is mcakyla i am 12 years old and i am in the 6th grade i go to rehobeth middle school and we have a science project coming up i do have a partner and her name is kelsey.all together we have to do a model of venus and a brosure(which is going to be hard)its going to be hard because i have to the brosure by myself and kelsey does the model…if you have any information about venus please tell me thank….bye everyone?!

  46. priscilla Says:

    Even Though Venus Is A Verry Hot Its Still A Beutifull Plannet Because It IS.

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