New Details on Venus’ Clouds from Venus Express

Article written: 10 Jun , 2008
Updated: 26 Apr , 2016
by

Mysterious clouds blanket Venus, obscuring our sister planet from view. These clouds billow up between 45 and 70 km above the surface, and in the upper part of the atmosphere, clouds swirl by at a rate of 300 km/h, driven by fierce winds. Composed mainly of sulfuric acid along with chlorine and fluorine, these clouds wouldn’t be friendly to life as we know it, but still, their mysteries beckon us. The science team from the European Space Agency’s Venus Express has been imaging the planet’s enigmatic atmosphere, and has released new images in several different wavelengths that provide new details on the clouds of Venus.

The Venus Monitoring Camera (VMC) on board Venus Express has been observing the top of the cloud layer in visible, near-infrared and ultraviolet wavelengths. Ultraviolet observations have shown a wealth of new details including a variety of markings created by different concentrations of different aerosols located at the top of the cloud layer.

The image above is a global view of the southern hemisphere of Venus, obtained from a distance of 30,000 km, with the south pole at the bottom and the equator at the top.

The appearance of the clouds changes dramatically from the equator to the pole. At low latitudes, the shapes are spotty and fragmented. Like water boiling in a pot, the clouds move because of convection, powered by the radiation of the sun heating the clouds and atmosphere. The brighter area visible on top of the darker cloud deck is made of freshly formed droplets of sulfuric acid.

At mid latitudes, the scene changes — convective patterns give way to more streaky clouds indicating that convection is weaker here, as the amount of sunlight absorbed by the atmosphere decreases.

At high latitudes, the cloud structure changes again. Here it appears as a dense, almost featureless haze forming a kind of polar cap or ‘hood’ on Venus. The dark, circular feature visible at the lower edge of the image is one of the dark streaks usually present in the polar region, indicating atmospheric parcels spiraling around and towards the pole.

Additional images provide close-up views of the structures described above and show details never seen before.

The second image zooms in on the equatorial region, showing details of the cloud top and of the bright areas made from sulfuric acid, from 20,000 km.

The third image is a close-up on the transition region between the equatorial regions dominated by convection and the mid-latitudes populated by streaky clouds. This region is located at about 40-50 degrees latitude and was imaged from a distance of about 15,000 km. The way the transition between structures and dynamics so different from each other occurs, is one of the outstanding enigmas in our understanding Venus.

Original News Source: Space Daily


8 Responses

  1. Jorge says

    I’m not sure I like how they chose to colourise these photos. They are making the clouds look too much like Earth’s (in the bottom picture especially), while they could hardly be more different. People might get the wrong impression if they aren’t aware of how artificial the colours are (the photos are not shot in the visible part of the spectrum, but in the ultraviolet).

    (Oh, and Nancy, you got a “the the” on the first paragraph)

  2. Member

    Hi, hi, Nancy, Nancy! (giggle… ;))

    Hey, I really liked this article. It caught my eye because I like to observe Venus with a deep violet filter and the effect is much the same.

    Or is the affect?

    Good job!

  3. David says

    I think the images are important in bringing out contrasts that would not otherwise be apparent, and I therefore appreciated the effort in illustrating a different perspective. The same technique is used with other planetary observations and should not be discounted. If someone gets the wrong impression from viewing the evidence, they can always take a closer look at other images and/or data.

  4. Jorge says

    I’m far from thinking the illustration of contrasts and stuff like that is not done properly. It is. The images are great in that regard. I just think the colour choice might be different and still convey the same information, without inducing even more in error the uninformed.

    There’s way too much disinformation in astronomy in particular and science in general to make it clever to try not to inadvertently enhance it.

  5. David says

    Jorge,
    Point taken. However, I would argue that we need to play a good game of offense rather than defense. Defending against the vast array of individuals (I’m being charitable in calling them a neutral term) who subscribe to “disinformation” is like counting the stars. An endless, tedious task. Let’s use pics like the ones posted to keep them guessing….or at least enourage them to look beyond the length of their nose. Or better yet, lets simply ignore them.

  6. Jorge says

    No, David, I can’t agree with that.

    For a number of reasons, but I think it’ll suffice if I explain you one: It’s the vast array of uninformed individuals that chooses the small array of uninformed politicians that decide how and when to finance scientific endeavours and what to do with scientific knowledge.

    If their ignorance isn’t fought by the people who know best, they’ll become dumber and dumber, will elect dumber and dumber politicians and the money dwindles or is wasted on nonsense and knowledge is discarded or (even more) severely misused. And we just cannot afford that to happen. There’s too much at stake.

    That’s why sites such as this one are so important, BTW.

  7. Chicago Astronomer Joe says

    Here is a question that I and others have had about the Russian Venus landers that has not really been answered.

    It is understood that on the surface of the planet, it incredibly hot…so much that the metal on the machines apparently melted. Couple with the high pressure and corrosive atmosphere…it’s a nasty place.

    Then how…could the cloth-like material that made up the parachute, have survived for any amount of time on the way down to the surface?

  8. Joshua Brotman says

    Chicago Astronomer Joe

    Most of the early landers never got around this problem: they crash landed. The few with parachutes actually ejected the parachutes before they reached an altitude hot enough to burn it up. Then they simply crash landed on luck… and many probes simply made atmospheric measurements without intentions of making it to the surface.

Leave a Reply