Can dark streaks in Venus’ clouds for signs of alien life?

An artist’s impression of the uncrewed Venus Atmospheric Maneuverable Platform (VAMP) to fly by Venus’ clouds.

(Northrop Grumman)

The question of life on Venus , of all places, is intriguing enough that a team of AMERICAN and Russian scientists are working on a proposal for a new mission to the planet — the name Venera-D is considering including the search for life in its mission goals.

If everything goes as planned, a unmanned aerial vehicle (UAV) on a day sail the thick sulfuric-acid clouds of Venus to help determine if dark streaks that seem to absorb uv-radiation can be evidence of microbial life.

Venus has long been a focus of attention of the Russian planetary science, which is the proud legacy of the record-breaking Venera probes that landed on the Venusian surface in the late 1970s and early 1980s. [Mysterious Venus: 10 Weird Facts]

With many questions remaining unanswered, the collective mission of Roscosmos and NASA, if approved, would allow the orbiter to launch in the direction of Venus in 2025 with the aim of remote-sensing observations of the planet and the atmosphere; implementing a probe on the surface, and search for the future of the landing sites.

Among the various possible additions to the mission are a little sub-orbiter to study Venus’ magnetosphere, and a balloon or a UAV measurements of the atmosphere over a long duration.

Should the UAV be approved, its main purpose would be to take meteorological measurements in order to determine why the atmosphere rotates so fast in comparison with the surface, a phenomenon known as super-rotation . This rapid rotation was discovered in the 1960s by astronomers to follow the movement of the dark lines in the atmosphere. Puzzlingly, astronomers do not know what the origin and composition of these dark streaks, nor do they understand why the stripes are still not mixed with the rest of the atmosphere and why they absorb ultraviolet light.

“These are questions not yet fully explored, but I’m shouting as hard as I can, to say that we should investigate,” said Sanjay Limaye, an atmospheric scientist from the University of Wisconsin, Madison and a former chairman of NASA’s Venus Exploration Analysis Group (VEXAG).

According to Limaye, the nature of the UV-absorber is completely unknown. It could be particles mixed in the clouds, or a substance that is dissolved by the droplets of sulphuric acid, or it can be crystalline in nature, like ice cream. Iron chloride has been proposed, but there is no confirmed mechanism that can loft particles of iron-chloride 31 to 37 miles (50 to 60 kilometers above the surface, especially if the wind near the surface only blowing faintly through the dense lower atmosphere.

Life in the clouds?

A more exciting explanation for the dark streaks is that they are evidence of microbial life . “It is a possibility we can’t look at,” said Limaye, who is a member of the Venera-D science definition team.

Finding life at high altitude in the atmosphere of a planet would be useful. After all the microbes found at similar altitudes in the atmosphere of the Earth. The challenge for life on Venus is the planet of extreme temperature. The surface, at 864 degrees, hot enough to melt lead, and the surface pressure of 92 bar is the equivalent of almost 0.6 km under water.

However, in a region beginning approximately 31 km in the height and the extension of 7.5 miles to the outside is a sweet spot where the temperature ranges between 86 degrees F and 158 degrees F, and the pressure is similar to that on Earth. Life can survive in this zone, where the dark stripes UV-absorber is found.

Intriguing, the sulfuric acid droplets in the clouds are not necessarily a show-stopper to life. Earlier Venera missions detected elongated particles in the lower cloud layer, approximately 1 micron long, approximately the width of a small bacterium. These particles can be coated in a ring-shaped polymers of eight sulfur atoms, the so-called S8 molecules, which are known to exist in Venus’ clouds and which are impervious to the corrosive effects of sulphuric acid, researchers said. [5 Bold Claims of Alien Life]

In addition, S8 absorbs uv light and re-emit in the visible wavelengths. If the particles are bacteria, they would be covered in the S8, which makes them resistant to the corrosive action of sulfuric acid. It is even said that the S8 is as a result of microbial activity. Is this the key to life on Venus?

“I can’t say that there is microbial life in Venus’ clouds ,” Limaye said. “But that does not mean that it is not there. The only way to learn is to go there and taste the atmosphere.”

Powered flight

The original Russian plan for the Venera-D featured balloons patrolling in the atmosphere, but balloons are not very agile and not necessarily in the regions with the dark stripes. A solar-powered UAV would have a much greater chance, according to Limaye.

“The idea is that, with a sufficiently large wingspan you can generate enough power and actually fly through the atmosphere of Venus, with electric propellers, for a very long time,” Limaye said.

Descending hypersonically in the atmosphere after detaching from the orbiter, the UAV would be filled with hydrogen or helium gas, the buoyancy of a nominal variable height of 31 km, making it glide through the clouds, while the move by the night-time hemisphere. In daylight, the solar-powered propellers would kick in and increase the vessel height is approximately 37 km.

In the course of three to four days, the craft could move around the planet along the upper layers of the atmosphere of the “super-rotation,” the strange phenomenon, where the atmosphere seems to be disconnected from the solid planet rotates much faster. The UAV would therefore be able to explore the clouds at different heights, the moving of the air mass air mass, regions with the UV-absorbent to regions devoid of them, sampling and measurement of the composition of the atmosphere.

The aerospace company Northrop Grumman has already independently developed a concept for a Venusian UAV, called VAMP (Venus Atmospheric Maneuverable Platform), that would be a giant 180-foot wingspan and are designed to function in the atmosphere for at least a year.

The ‘D’ in the Venera-D’s name stands for “dolgozhivushaya,” which in Russian means “long duration.” This was originally intended to be the hope of keeping a lander operating on the Venusian surface for days or weeks, although the poor conditions on the surface mean that realistically, the most that all the lander could survive is only a few hours. Instead, the UAV, constantly circling around Venus, would the mantle of long duration.

The final report describing the science goals of the Venera-D mission will be submitted to Roscosmos and NASA at the end of January 2017, after which the two space agencies have to decide whether or not they contribute to the mission. An answer is not expected until the end of 2017 at the earliest.

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