Transit of Venus today may reveal the "Mysterious Arc of Venus"

From Dr. Tony Phillips Science at NASA

Three photos of the arc of Venus observed during the planet's 2004 transit by amateur astronomer André Rondi near Toulouse, France.

Three photos from the Arc of Venus observed during the planet’s 2004 transit by amateur astronomer near Toulouse, France. Image Courtesy of André Rondi.

When Venus transits the sun on June 5th and 6th, an armada of spacecraft and ground-based telescopes will be on the lookout for something elusive and, until recently, unexpected: The Arc of Venus.

“I was flabbergasted when I first saw it during the 2004 transit,” recalls astronomy professor Jay Pasachoff of Williams College. “A bright, glowing rim appeared around the edge of Venus soon after it began to move into the sun.”

For a brief instant, the planet had turned into a “ring of fire.”

Researchers now understand what happened. Backlit by the sun, Venus’s atmosphere refracted sunlight passing through layers of air above the planet’s cloudtops, creating an arc of light that was visible in backyard telescopes and spacecraft alike.

It turns out, researchers can learn a lot about Venus by observing the arc. Indeed, it touches on some of the deepest mysteries of the second planet.

The arc of Venus photographed in 2004.

› View larger The arc of Venus photographed in 2004 by Riccardo Robitschek and Giovanni Maria

Caglieris of Milan, Italy. “We do not understand why our sister planet’s atmosphere evolved to be so different than Earth’s,” explains planetary scientist Thomas Widemann of the Observatoire de Paris.

Earth and Venus are similar distances from the sun, are made of the same basic materials, and are almost perfect twins in terms of size. Yet the two planets are wrapped in stunningly dissimilar blankets of air. Venus’s atmosphere is almost 100 times more massive than Earth’s and consists mainly of CO2, a greenhouse gas that raises the surface temperature to almost 900°F. Clouds of sulfuric acid tower 14 miles high and whip around the planet as fast as 220 mph. A human being transported to this hellish environment would be crushed, suffocate, desiccate, and possibly ignite.

For the most part, planetary scientists have no idea how Venus turned out this way.

“Our models and tools cannot fully explain Venus, which means we lack the tools for understanding our own planet,” points out Widemann. “Caring about Venus is caring about ourselves.”

One of the biggest mysteries of Venus is super-rotation. The whole atmosphere circles the planet in just four Earth days, much faster than the planet’s spin period of 243 days. “The dynamics of super-rotation are still a puzzle despite a wealth of data from landmark missions such as NASA’s Pioneer Venus, Russia’s Venera and VEGA missions, NASA’s Magellan and more recently ESA’s Venus Express.”

The arc of Venus as seen by NASA's TRACE spacecraft in 2004.

› View larger The arc of Venus as seen by NASA’s TRACE spacecraft in 2004. Credit: NASA/Trace/LMSAL

This is where the Arc of Venus comes in. The brightness of the arc reveals the temperature and density structure of Venus’s middle atmosphere, or “mesosphere,” where the sunlight is refracted. According to some models, the mesosphere is key to the physics of super-rotation. By analyzing the lightcurve of the arc, researchers can figure out the temperature and density of this critical layer from pole to pole.

When the arc appeared in 2004, the apparition took astronomers by surprise; as a result, their observations were not optimized to capture and analyze the fast-changing ring of light.

This time, however, they are ready. Together, Pasachoff and Widemann have organized a worldwide effort to monitor the phenomenon on June 5th, 2012. “We’re going to observe the arc using 9 coronagraphs spaced around the world,” says Pasachoff. “Observing sites include Haleakala, Big Bear, and Sacramento Peak. Japan’s Hinode spacecraft and NASA’s Solar Dynamics Observatory will also be gathering data.”

Pasachoff has some advice for amateur astronomers who wish to observe the arc. “The best times to look are ingress and egress–that is, when the disk of Venus is entering and exiting the sun. Ingress is between 22:09 and 22:27 UT on June 5th; egress occurs between 04:32 and 04:50 UT. Be sure your telescope is safely filtered. Both white light and H-alpha filters might possibly show the arc.”

Related Links

› NASA 2012 Venus Transit site

› View more from the photo series

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Craig S

Always have to question scientists that state the 900 F temperature on Venus is due to the massive amounts of CO2.

Allan MacRae

Perhaps all that “missing sink” CO2 somehow winds up on Venus.
sarc/off

Heggs

“Our models and tools cannot fully explain Venus, which means we lack the tools for understanding our own planet,” points out Widemann.
——
I thought we were going to burn, the models say so!

“Earth and Venus are similar distances from the sun”
Why is this completely untrue statement so commonly spoken or written? Venus is around 30% closer to the sun and receives ~9x the energy from the sun. That’s about as dissimilar as you can get.

Jer0me

So there is 100x Earth’s atmosphere on Venus, making it extremely dense, but it’s not that making it hot, it’s CO2? Codswallop.
Apart from that political nod, it is all very interesting!

noloctd

What a pooprly written article with some factual errors (or deliberate politcal distortions). “Similar distance”, hah. Somebody at NASA needs to read the textbook from Physics 101.

Casper
George V

“Earth and Venus are similar distances from the sun, …”
“Our models and tools cannot fully explain Venus, which means we lack the tools for understanding our own planet,” points out Widemann.”
If NASA’s tools currently indicate Venus and the Earth are at similar distances from the sun, perhaps the first tool that should be acquired by NASA is a brain.
George V.

Jonathan Smith

“Our models and tools cannot fully explain Venus, which means we lack the tools for understanding our own planet,” points out Widemann. “Caring about Venus is caring about ourselves.”
How dare he, the science is settled, our models can predict what the Earth’s atmosphere will do with utter precision. Ignore the last 15 years or so of no warming, that’s a minor glitch that will soon be ‘adjusted’ out.
JS

Just a couple of comments, here:
“…Earth and Venus are similar distances from the sun…”
WTF?
Venus, 67.2 million miles from sun.
Earth, 93 million miles from sun.
Difference of 25.8 million miles.
That’s a “similar distance”?
“…Yet the two planets are wrapped in stunningly dissimilar blankets of air. Venus’s atmosphere is almost 100 times more massive than Earth’s and consists mainly of CO2, a greenhouse gas that raises the surface temperature to almost 900°F…”
…while the Earth’s atmosphere consists mainly of water vapor – and CO2 levels are on the order of parts per million, and beneficial to life on our planet.
They’re just trying to get in the usual “CO2 causes the heat there, it must be the cause of the heat on Earth.
Closer to the heat source doesn’t matter.
“…Our models and tools cannot fully explain Venus, which means we lack the tools for understanding our own planet,” points out Widemann. “Caring about Venus is caring about ourselves…”
We care about Venus – we really do. Climate Scientist Bill McKibben is trying to connect the dots now, and insisting that the CO2 levels on Venus are brought back down to the magic 350ppm.
BTW, if a planet can have that much CO2 naturally, where did it all come from?

Venus is water free and there was no dry process to convert the CO2 to O2 as happened on earth. Biological processes need water to work. Earth could have had the same dense atmosphere if it were not sequestered into the rocks as limestone.
I will argue with the super GHG cause of Venusan heat. That dense atmosphere is affected by the gravity which will add heat due to adiabatic compression. This works on Jupiter which emits far more heat than it receives and has an atmosphere of hydrogen/helium. A simple application of the combined gas laws will produce the required temperature without any GHG theory.

tckev

It would be interesting to know what Dr. Tony Phillips thinks of a recent piece –
http://wattsupwiththat.com/2010/05/08/venus-envy/
It certainly appears to have plenty of merit to it, how does the man from NASA feel about it?

Patrick

I see many have already picked up on the distance thing. Is this *really* from NASA?

blogagog says:
June 5, 2012 at 4:08 am
Venus is around 30% closer to the sun and receives ~9x the energy from the sun.
No, only 2x.

Mike McMillan

blogagog says: June 5, 2012 at 4:08 am
“Earth and Venus are similar distances from the sun”
Why is this completely untrue statement so commonly spoken or written? Venus is around 30% closer to the sun and receives ~9x the energy from the sun. That’s about as dissimilar as you can get.

Only about twice the energy.
“Venus’s atmosphere is almost 100 times more massive than Earth’s and consists mainly of CO2, a greenhouse gas that raises the surface temperature to almost 900°F.”
The high temperature has little to do with CO2, and everything to do with the surface pressure. Using the adiabatic lapse rate for the Venusian atmosphere, if you ascend to where the pressure is 1 bar, earth normal, the temperature isn’t that far off from ours, especially considering the greater insolation. If our air atmosphere were at 90 bar, we’d be red hot, too.

Steve C

-CLICK-
The sound of another brain turning off on hearing (yet again) the unproven claim that Venus’ surface temperature is due to a “greenhouse effect”. Wanna change that? Show me!
“we lack the tools for understanding our own planet”. Yep. That you have shown me, over and over!

Jens Bagh

Please explain why the Venus atmosphere is so much denser than the earth’s given that Venus is smaller, have less mass and lower gravitational acceleration.

Brian H

ddddd
That’s to replenish the shortage of “d”s.
“A human being transported to this hellish environment would be crushed, suffocate, desiccate, and possibly ignite.”
“A human being transported to this hellish environment would be crushed, suffocated, desiccated, and possibly ignited.”
No problem, don’t mention it. You’re welcome.

Nat McQueen

Venus does have an atmosphere that is 97% CO2. However, its because the atmosphere is so thick and so much closer to the sun that causes the temperature to be so high. Not necessarily because its CO2.

Babsy

henrythethird says:
June 5, 2012 at 4:35 am
“BTW, if a planet can have that much CO2 naturally, where did it all come from?”
Why Big Oil and Big Coal of course! Their slimy tentacles of death, misery, and corporate profits aren’t merely limited to Mother Gaia alone!

Owen in GA

Venus is 2/3 the distance from the sun as the Earth. Intensity goes as the inverse of the square of the distance, so Venus receives 9/4 the solar input as the Earth. (sarc)Of course climate science has told us that the sun has no effect on temperature so it obviously must be the CO2 that makes the difference(/sarc).
Seriously, has Hanson infected EVERYTHING at NASA?

Pamela Gray

There is greater than a random chance that scientists will be compelled to use Venus as a tale of caution regarding our own CO2 output. I believe what they are hoping to discover is not basic science about Venus’ atmosphere, but biased science about ours.

Peridot

I find the replies to this article very interesting and look forward to reading many more.
When asked about the ‘runaway greenhouse’ effect on Venus I have always answered that Venus is 30% closer to the sun and shoud be even hotter than it is. I put this down to the dense atmosphere reflecting much of the heat and light back into space (making Venus a very bright object in the sky). As Venus has been the way it is for a long time one would have thought a runaway greenhouse effect would have made it much, much hotter by now (even without heating due to the dense atmosphere, as I am reading above).
I am ready to be corrected on any of this, of course.

Jimbo

I could be wrong but I vaguely recollect that Co2 means nothing without the atmospheric pressure. Off the top of my head I think Mars is 95% Co2 and is a ‘similar’ distance to the sun (tongue in cheek).

NASA is clearly short of funding if it lacks the tools to discover that Venus and Earth are at similar distances from the Sun. If that were so we would periodically have a spectacular view of that planet looming up, not to mention the eventual spectacular collision. Venus is about 1/3 (67/93) closer to the Sun than Earth.
They also need extra funding to discover that CO2 does not cause absolutely everything including warming. A few more tools and they could check out the effect that the pressure has on the Venusian temperature. They could also investigate the water on Earth that is lacking on Venus.
This all just looks like yet another attempt to push the CAGW bandwagon out of the mud.

commieBob

A planet’s atmosphere should have a maximum temperature gradient. This would be determined by the point at which the density of the atmosphere at the surface becomes such that it floats upward and convection starts. Convection removes heat from the planet’s surface faster than any other process. Once convection starts, it takes much more energy to produce a degree of warming at the surface. Venus has a much denser atmosphere than Earth so its atmosphere should have a greater temperature at the surface.

Jason

“Venus’s atmosphere is almost 100 times more massive than Earth’s and consists mainly of CO2, a greenhouse gas that raises the surface temperature to almost 900°F.”
From what I can remember, the atmospheric pressure on Venus is 90 times that of Earth’s. This causes CO2 to become a more potent GHG. Yet, with that said, I remember talk of it not even being Venus’ main greenhouse driver. That distinction went to the thick sulfuric acid cloud layer, that allows Venus to see far less sunlight than here on Earth.
So what does that say about CO2 as a greenhouse driver, when it is not only a much more potent GHG in that enviroment, making up 96% of the atmosphere, but is still not the main green house driver?

Richard

@Jer0me “So there is 100x Earth’s atmosphere on Venus, making it extremely dense, but it’s not that making it hot, it’s CO2? Codswallop.”
CO2 does contribute, as does 100x Earth’s atmosphere and 9x Solar radiation.
CO2 is definitely a major contributing factor to the heat on its surface but it is 2760X the CO2 on Earth percentage-wise and since Venus has 100x our atmosphere, 276,000X the CO2 on Earth in absolute terms. When that much CO2 keeps in 9X the solar radiation, it should make things a little warmer.

scarletmacaw

I think the term ‘similar distances’ is fair. As the closest planet to Earth, Venus’ distance from the sun is ‘similar’ to Earth’s more so than any other planet. Of course, the difference matters since Venus receives about twice the solar energy per unit area that Earth does.
IIRC, Venus also has 4 times the amount of nitrogen than Earth. Earth may have lost 3/4 of it’s atmosphere in the collision that created the moon. The remaining CO2 on Earth was mostly converted to carbonates by chemical and biological processes in the oceans. Venus never had liquid water and thus retains it’s primordial CO2 atmosphere. It’s not Venus that’s odd, it’s Earth.
As far as water on Venus, the story I heard was that the water molecules were split into hydrogen and oxygen, with the hydrogen leaving the atmosphere and the oxygen oxidizing the rocky surface. I wonder. If Venus started out with four times the water found on Earth, then that’s a lot of oxygen. It would have to have penetrated the surface very deeply to be completely chemically bound to the rocks.

Marc77

Mars is also at a ‘similar’ distance from the Sun. It has about 20 times more CO2 per surface that the Earth, it’s atmosphere pressure is lower and it is cold.

immybrother

So if the wife weighs 150, and I’m 210, we will balance the teeter-totter at Goddard?

DesertYote

Venus does not have a big whopping atmosphere stripping moon. BTW, the moon use to be a lot closer to the earth.

ferdberple

Venus’s atmosphere is almost 100 times more massive than Earth’s and consists mainly of CO2, a greenhouse gas that raises the surface temperature to almost 900°F.
============
The atmosphere of both Mars and Venus is mainly CO2. One is very hot, the other very cold. This difference is much greater than can be explained by the difference in radiation due to their distance from the sun.
Jupiter, which is much farther away from the sun than Venus, has a much higher surface temperature than Venus. At an atmospheric pressure of about 10 earth atmospheres, temperatures on Jupiter are similar to those of Earth. Yet Jupiter is much farther away from the sun than earth.
None of this can be explained in terms of greenhouse gas. The common factor is the amount of atmosphere and the distance from the sun. The more atmosphere, the warmer the surface. The more solar radiation, the warmer the surface.
Keep in mind that gas molecules do not travel in straight lines. They travel in a curved trajectory under the influence of gravity, and this curved trajectory has minimum kinetic energy at the top of the trajectory and maximum kinetic energy at the bottom of the trajectory.
Thus, the temperature of a single gas molecule changes as it moves under the influence of gravity, independent of any external radiation, and reaches a maximum the lower it travels in the atmosphere. We observe this as the atmospheric lapse rate, which is present on all planets with atmosphere.

Rod Everson

Yes, the article is written to suck anyone not paying attention to skeptical arguments into thinking that “there but for the grace of God go I.” Hence, the claim of being similar distances from the sun and the mention of CO2. Although the line “A human being transported to this hellish environment would be crushed, suffocate, desiccate, and possibly ignite,” was interesting, I hope the hopelessly addicted CO2 worshipers aren’t driven to despair by it.
Minor point, but the picture is initially confusing, and even after figuring out that the little arc is Venus in the three pictures, it’s not clear how Venus could be moving into the sun in the order they’re presented. Either Venus is exiting the sun’s arc in the sequence, or, if entering, the pictures are presented in reverse order. The article refers to moving into the sun (“A bright, glowing rim appeared around the edge of Venus soon after it began to move into the sun,”) but the pictures as presented would appear to represent its exiting the sun.
It’s also confusing because the sun is blacked out. Some labeling would have been helpful, as well as a caption indicating that in the sequence Venus is leaving the sun (or reverse the sequence to agree with the text.) Frankly, at first I thought the large ring was Venus in front of the sun (like the recent moon pix) and the arc was some strange phenomenon in the atmosphere of Venus. It took reading the article to sort it all out.

J.Gommers

Take a look at the ESA data, only the temperature of the surface layer is high, over 700 K.
Velocities at the surface are low due to the high density, almost no upward convection.
The atmosphere resembles a solar saline heat pond, not heated by sunlight but by the planet’s surface, there is volcanic activity.

John F. Hultquist

henrythethird says:
June 5, 2012 at 4:35 am
“…while the Earth’s atmosphere consists mainly of water vapor –

WUWT?

ferdberple

“Our models and tools cannot fully explain Venus, which means we lack the tools for understanding our own planet,” points out Widemann.
============
You cannot understand because you are trapped in the equation CO2 = GHG = Temperature.
You have ignored the more fundamental equation. Gravity + Mass = Kinetic Energy = Temperature

When I read this distorted pablum coming out of NASA, I realize once again how my tax dollars are wasted by this out-of-control federal government.

jayhd

All the factual errors and misstatement of facts pointed out by previous commenters make me wonder what’s going on at NASA. It’s obvious Dr. Tony Phillips (whatever his doctorate is in, it certainly has nothing to do with astronomy) doesn’t have anyone fact check his output. This is actually embarrassing.
Jay Davis

Christopher Simpson

John Marshall says:
June 5, 2012 at 4:55 am
“Venus is water free…”
My understanding is that the present understanding (another way of saying that we’re looking at layers of guesswork here) is that our water came from outer space in the form of comets pummelling the Earth for a couple of quintillion years. Since Venus is a “similar” distance, why is it water free?
I’m not snarking (I’ve got Comics Curmudgeon for that) — I’m asking for real.

Ellen

Ignite? Not in a CO2 atmosphere!

Billy Liar

If you were Dr Tony Phillips wouldn’t you be embarrassed to have your name associated with an article containing such schoolboy howlers?

LarryD

I understood that Earth’s early atmosphere was very like Venus’ current atmosphere in composition and mass. The most crucial difference was the presence of oceans of water on Earth. This enables the combination of CO2 with calcium and manganese, eventually sequestering most of the CO2 as carbonate minerals, leaving Earth’s atmosphere dominated by nitrogen.

adolfogiurfa

It´s because of a “flabbergasted” consensus which impedes thinking out of a “convenient” box. Time to revisit TODAY, as Venus crosses the Sun, the persecuted and “indexed” work of Immanuel Velikovsky “Worlds in Collision”

Interestingly enough, at the 92 atmospheres of pressure at the surface of Venus, carbon dioxide could best be called a supercritical fluid rather than a gas. Perhaps its atmosphere could better be referred to as an ocean. Here’s a link to the phase diagram and critical point. Cheers –
http://www.science.uwaterloo.ca/~cchieh/cact/c123/phasesdgm.html

adolfogiurfa

Venus does not have a magnetic field then it cannot spin as fast as the earth, however its atmosphere, being ionized generates a corresponding magnetic field so it spins faster:
Why do planets spin?: (Warning: You will be committing a SIN against the “Consensus Church” if you see the following) 🙂
http://youtu.be/EkU_JmtH3PU

darrylb

Flabbergasted when he (they) first saw it??
Is anyone else flabbergasted that it wasn’t immediately quite obvious that he was observing
refracted light— and perhaps they should be looking for refraction of other frequencies of EM
waves.

F. Ross

Wikipedia:

Venus’s atmosphere is almost 100 times more massive than Earth’s and consists mainly of CO2, a greenhouse gas that raises the surface temperature to almost 900°F.

The good Dr. Phillips probably got his Venus info from Wikipedia …or Hansen.
I think he would get a strong argument from Dale Huffman. http://theendofthemystery.blogspot.com/ regarding the cause of high temps on Venus.

Brian H

Christopher Simpson says:
June 5, 2012 at 9:13 am
John Marshall says:
June 5, 2012 at 4:55 am
“Venus is water free…”
My understanding is that the present understanding (another way of saying that we’re looking at layers of guesswork here) is that our water came from outer space in the form of comets pummelling the Earth for a couple of quintillion years. Since Venus is a “similar” distance, why is it water free?

One suggestion was that the battle to cool Venus down enough for water to hang around was lost early on, and it “boiled away”, breaking down in the upper atmosphere and losing the hydrogen to space.
Associated questions: where did the O2 for the CO2 come from? Maybe from the early water. So where did the C for the CO2 come from? Maybe the carbonaceous chondrites that made up much/part of the early asteroidal material that made up the planet.
Multifaceted mysteries abound …

Christopher Simpson

Brian H says:
June 5, 2012 at 10:02 am
One suggestion was that the battle to cool Venus down enough for water to hang around was lost early on, and it “boiled away”, breaking down in the upper atmosphere and losing the hydrogen to space….

Thanks, Brian. I did wonder about that. I guess our “similar” distances from the Sun aren’t quite so similar after all.
Of course, now there’s the question of why Mars doesn’t have any water, since it was likely bombarded as heavily as Earth by the comets. Would the explanation here be that it’s lower gravity worked against the creation of an atmosphere of sufficient density to stop the water from boiling away in vacuum?

jorgekafkazar

John Marshall says: …I will argue with the super GHG cause of Venusan heat. That dense atmosphere is affected by the gravity which will add heat due to adiabatic compression. This works on Jupiter which emits far more heat than it receives and has an atmosphere of hydrogen/helium. A simple application of the combined gas laws will produce the required temperature without any GHG theory.
Oh, jeez, here we go again.
jayhd says: …It’s obvious Dr. Tony Phillips (whatever his doctorate is in, it certainly has nothing to do with astronomy) doesn’t have anyone fact check his output….
Based on Venus and Earth having “similar” distances from the sun, my guess is Tony is an astrophysicist. They’re happy if the decimal point is in the right place.
adolfogiurfa says: …Time to revisit TODAY, as Venus crosses the Sun, the persecuted and “indexed” work of Immanuel Velikovsky “Worlds in Collision”
They’re not persecuted; they’re ignored as absolute drivel. And they are not in the Vatican’s Index Librorum Prohibitorum, either.