From Science @NASA Japanese Spacecraft Approaches Venus
For the next few months, Venus will be softly resplendent in the evening sky, a treat for stargazers – but looks can be deceiving.
Consider this: The Venusian surface is hot enough to melt lead. The planet’s 96% carbon dioxide atmosphere is thick and steamy with a corrosive mist of sulfuric acid floating through it. The terrain is forbidding, strewn with craters and volcanic calderas – and bone dry. Takeshi Imamura can’t wait to get there.
Imamura is the project scientist for Akatsuki, a Japanese mission also called the Venus Climate Orbiter. The spacecraft is approaching Venus and will enter orbit on December 7, 2010. Imamura believes a close-up look at Venus could teach us a lot about our own planet.
“In so many ways, Venus is similar to Earth. It has about the same mass, is approximately the same distance from the sun, and is made of the same basic materials,” says Imamura. “Yet the two worlds ended up so different. We want to know why.”
Although a parade of U.S. and Soviet spacecraft has visited Venus since 1961, no one yet knows how it became Earth’s “evil twin.” Did it suffer from a case of global warming run amok – or something else? When Akatsuki reaches Venus in December, it will begin to solve some of the mysteries hidden in the thick Venusian atmosphere.
“By comparing Venus’s unique meteorology to Earth’s, we’ll learn more about the universal principles of meteorology and improve the climate models we use to predict our planet’s future.”
Particularly puzzling is Venus’s “super-rotation.” Fierce, blistering winds propel an atmosphere filled with storms and sulfuric acid clouds in a churning maelstrom around Venus at over 220 miles per hour, 60 times faster than the planet itself rotates.
“Venus’s atmosphere is in perpetual motion, as if a living thing,” says Imamura.
Within this swirling cauldron are other Venusian riddles to be solved: What is the origin of the 12-mile thick layer of sulfuric acid clouds that shrouds the planet? And how does Venus’ lightning crackle through this strange brew?
Akatsuki, bristling with cameras, will circle the exotic planet’s equator in an elliptical orbit for at least 2 years, monitoring the atmosphere at different altitudes using various wavelengths (IR, UV, and visible). With this data and data from the spacecraft’s radio dish, scientists will reconstruct a 3D model of the atmosphere’s structure and dynamics.
“The spacecraft’s orbit will match the circulation of Venus’s clouds, allowing the instruments to monitor cloud movement from directly above for 20 hours at a time. We’ll assemble the images to produce a cloud motion time-lapse movie, much like a weather forecaster on television might show you of Earth.”
The instruments will also scrutinize the planet’s surface for volcanic activity that could be contributing to the sulfur contents of the atmosphere. “If any active volcanoes are spouting hot lava on Venus, one of our infrared cameras will detect the thermal emission,” says Imamura.
In addition, Akatsuki’s Lightning and Airglow Camera will hunt for lightning in order to settle a longstanding debate. “On Earth, the standard theory of lightning requires water ice particles on which positive or negative charges are induced via collisions,” explains Imamura. “But there are no ice particles in Venus’s hot, dry atmosphere–so how does Venusian lightning get started? It may be that charge separation can occur in sulfuric acid clouds–or perhaps some unknown solid particles exist in the atmosphere and play an important role.”
Imamura can scarcely contain his curiosity. “As a young boy I loved to watch clouds, stars, oceans, rocks, and creatures. I wanted to understand why they look and behave as they do. Now I am curious in the same way about Venus. Nature is so full of mysteries!”
Beginning in December, some of Venus’s mysteries will be revealed. Stay tuned.
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approximatly the same distance from the sun? Did they move Venus on me while I slept?
The distance form the sun would increase the effective energy input from the sun by a huge amount , that alone would account for some of the excess energy in then Venusian atmosphere.
Science should learn more from all of these satellite visits to our neighboring planets than the actual data collected. The key fact that is determined in almost each and every case is that our theories of what these planets are like and how they developed and function are invariably wrong. Perhaps the use of the words; “we think, theoretically, perhaps, or we are not sure”–should be used more often until the actual data is collected. Same goes for all branches of science. This article does fairly well in that respect.
Saying our 2 planets are approximately the same distance from the sun is misleading. Yes, maybe relatively speaking, but the difference is enough to have a big impact on the amount of heat and irradiance cooking the planet. I suspect that even if Venus had a similar atmosphere to earth, it would still be too hot to live there, just not hot enough to melt lead. Maybe the polar regions might be cool enough to survive.
I think Earth was fortunate enough to be struck by a huge comet when the moon was formed
Japan? December 7th?
So they are trying to find out why Venus’ atmosphere is acting like a giant lead-acid car battery?
This mission should have finding the cause of the Venus ‘greenhouse effect’ as a priority.
I think the high temperature at the surface of Venus is caused by the high pressure of the atmosphere, not its chemistry ( mainly CO2).
The same effect is seen on all the planets in our solar system.
I recommend this by Alan Siddons
http://www.ilovemycarbondioxide.com/pdf/Rethinking_the_greenhouse_effect.pdf
Men are from Mars, Women are from Venus
We can check out the women that were left behind.
Must be very Hot chicks if it can melt lead.
“.. similar to earth” ? Where to start? Ground level atmospheric pressure 92 x earth’s. No water. Rotation (not orbital) period 243 days. No apparent volcanic activity for half a billion years. Which earth is Takeshi Imamura living on?
Venus – Sun 67.2 million miles (108.2 million km)
Earth – Sun 93 million miles (149 million km)
Mass of Earth 5.98 × 1024 kg
Mass of Venus 4.868 x 1024 kgs
“In so many ways, Venus is similar to Earth. It has about the same mass, is approximately the same distance from the sun, and is made of the same basic materials,” says Imamura. “Yet the two worlds ended up so different. We want to know why.”
some pretty generous approximations there Ikeshita San …..
@View from the Solent:
“Rotation (not orbital) period 243 days.”
To be more precise, the Venus sidereal period (full rotation relative to the stars) is 243 Earth days. The Venus synodic period (“day” or rotation relative to the sun) is almost 117 days.
I wonder how warm we would be, here in Dallas, if the summer sun was shining for (117/2)*24 = 1404 hours.
“Beginning in December, some of Venus’s mysteries will be revealed. Stay tuned. ”
Absolutely!!!
Not sure we’re going to learn much if Takeshi Imamura is going to observe and process results through a ‘lens’ that Venus is “In so many ways, Venus is similar to Earth“.
It is obviously nothing like Earth and its atmosphere lacks the vital gas H20, which is essential for the hydrological cycle that controls our climate. Venus has an atmosphere with 96% carbon dioxide, while that of Earth has only a 0.039% trace.
I think it unlikely that we will learn anything about the climate of Venus which will assist in us in understanding about climate on Earth. But hey! he had to get the C word into the budget proposal somehow to get the satellite into orbit.
“is approximately the same distance from the sun”
More subtle nonsense!
The average surface temperature of Venus is about 462C.
If you use the most basic mathematical model and calculate the surface temperature of the Earth if moved into the same orbit of Venus, the Earth would have an average surface of 391C.
I read an interesting paper on planetary atmospheres but it never gave the reason behind what was shown about each atmosphere. It had one very interesting graph with the eight bodies’ atmospheres traits plotted together and normalized in millibars.
I would like them to solve the mystery why the atmospheres of Venus, Earth, Jupiter, Saturn, Uranus, Neptune, and Titan all have a tropopause very near to 100 millibar, they all also all have cloud tops at this level near their equators. Venus has its sulfuric acid clouds there. Earth has water vapor clouds there. Titan has its methane cloud tops there. Each body has different compounds making up the atmospheres yet the cloud tops are at basically the same pressure level and the lapse rates also turn near this relative pressure level.
Mercury has no real atmosphere so not included. At ground level Mars’s pressure is not even to 100 mb yet but was shown on this graph high above the other seven (less pressure).
Does this have to do with pressures above this line broadening begins to completely close the close harmonic vibrational gaps in the absorption/emission lines of all molecule types? Why 100 mb? What is so special about this 100 mb pressure level? If I can re-locate the link to that paper I will post it later.
Maybe this orbiter of Venus can help answer that curious question.
“”” “In so many ways, Venus is similar to Earth. It has about the same mass, is approximately the same distance from the sun, and is made of the same basic materials,” says Imamura. “Yet the two worlds ended up so different. We want to know why.” “””
Well we already know why Earth and Venus ended up different. For a start; they are different masses; and they are different distances from the sun; and they have different atmospheres; and then Venus doesn’t have much water so it wouldn’t have a steamy atmosphere like parts of earth do.
Other than that I think theya re on the right track in studying Venus; but it isn’t going to teach them diddley squat about earth climate.
“Directly above”? Not with an elliptical orbit! I’d settle for “in view” all the time.
With Venus’s slow rotation rate, it would take a rather distant orbit. It may be that the “20 hours” mentioned above is for the far end of the orbit. The inner part would zoom by real quick before the apparent motion slows down on the next outward climb.
Seems like a useful project, it’s been quite a while since there was a probed dedicated to Venus.
Venus is outside the habitable zone, Earth is within it. Big, big difference. According to the reconstructions, Earth did have an atmosphere very like Venus’, early on. Mostly CO2 and 90 times current mass, it’s believed that the CO2 was chemically sequestered into rock by forming carbonates in the presence of water.
So figuring out why Earth has oceans, and has had from very early on, is important. Pull Venus back to Earth’s orbit, give it oceans, wait a few million year and it would change a lot.
“Venusian” sounds so wrong, since the root is “vener-“. But “venereal” doesn’t quite have the right sound either…
While Venus is closer to the sun it’s clouds are so reflective that it actually absorb less sunlight than Earth. If you measure the blackbody temperature as seen from space, Venus is slightly colder than Earth:
http://nssdc.gsfc.nasa.gov/planetary/factsheet/venusfact.html
12 mile thick sulfuric acid clouds and clockwise retrograde rotation–very earth like, not.
But nah lets focus, just like the geniusless NASA, on CO2, because like ZOMG it’s so evil.
They spent many million dollars and gave the project scientist job to a guy that thinks Venus is like earth… man I want a job like that… I think the moon is like a big cheese ball. Now give me a job!
Come off it guys. 6 or 7 comments pointing out that Venus is different from the earth when the dude points it out himself.
It’s a “similar” size (the closest match of all the planets,)
It exists at a “similar” distance (the closest match of all the planets)
It’s a rocky planet of “similar” mass (the closest match of all the planets)
It’s made of the same basic materials (unlike the gas giants, and is possibly be the
best element for element by mass match for the earth. I didn’t research far enough.)
Which other planet is more earthlike? Didn’t think so.
I think ““In so many ways, Venus is similar to Earth. It has about the same mass, is approximately the same distance from the sun, and is made of the same basic materials,” is perfectly acceptable, especially considering
“Yet the two worlds ended up so different” is an admission that there are great differences between the two.
Paul says:
August 17, 2010 at 9:23 am
If you use the most basic mathematical model and calculate the surface temperature of the Earth if moved into the same orbit of Venus, the Earth would have an average surface of 391C.
I think there’s something wrong in that calculation. Mercury is half the distance to the Sun than Venus and therefore gets four times the radiance but it’s only 427C.
>> “In so many ways, Venus is similar to Earth. It has about the same mass, is approximately the same distance from the sun, and is made of the same basic materials,” says Imamura. “Yet the two worlds ended up so different. We want to know why.” <<
Let me defend this statement. First off, astronomy deals with ballpark figures, so the distances 0.7 AU and 1.0 AU are very close in astronomical terms. The bigger equivalence goes back to the origin of both planets. The material that formed planets at 0.7 AU and 1.0 AU would be expected to be of similar composition. Venus gets twice the solar energy that Earth receives, does that alone explain the different evolution of the two worlds?
Venus has about four times as much N2 as Earth and if you extrapolate that to other gasses that means that Earth has sequestered about 1/4 of the CO2 currently in Venus' atmosphere. To me this implies that the Earth is pretty good at eliminating CO2 quickly, and that also jibes with discrepancy between human CO2 output and atmospheric increase.
The shortage on Earth of 3/4 of the gas that Venus has fits well with the early collision theory. Looking at it in the other direction, Venus should have somewhere between one to four times as much water as Earth. Where did it go? Can that much water vapor boil off its atmosphere in 4.6 billion years? If that's the case, how much CO2 and N2 has also boiled off? Venus' upper atmospheric temperatures aren't all that high, but maybe there's a significant sub-solar hotspot.