Scientists studying Venus have discovered its strange dark spots are actually affecting the planet’s climate. Researchers have known about the ever-changing “splotches” on the Venusian surface for more than a century. But they have however never been explained, with some experts even suggesting they could be evidence of alien life.
Venus’ hot, harsh atmosphere is thick with carbon dioxide and sulphuric acid.
Atmospheric gases circulate amid cloud layers according to perplexing patterns.
These Venusian clouds contain strange, dark patches, called “unknown absorbers” because they absorb large amounts of solar radiation.
Now, a team of scientists led by Technical University of Berlin researcher Dr Yeon Joo Lee, has shown these unknown absorbers are affecting Venus’ weather.
On Venus, as on Earth, the energy driving the atmosphere’s winds derives from the Sun.
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After studying a trove of data from the European Space Agency’s (ESA) Venus Express and NASA’s Hubble Space Telescope, the researchers discovered a relationship between the planet’s clouds and winds.
The clouds absorb solar radiation, causing changes to its temperature, which in turn affects wind patterns.
The unknown absorbers appear to play a role in this process by affecting the planet’s albedo, meaning the amount of energy reflected back to space.
Dr Sanjay Limaye, of the University of Wisconsin-Madison and the paper’s co-author, said: “It is hard to conceive of what would cause a change in the albedo without a change in the absorbers.”
Because it is difficult to explain the absorbers’ changes with our reference to alien life, Dr Limaye has explored the possibility they might be microorganisms.
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The idea of life existing in the Venusian atmosphere dates back to a 1963 paper co-authored by revered American astronomer Dr Carl Sagan.
Dr Limaye observed how particles making up the dark patches in Venus’s clouds resemble microorganisms in Earth’s atmosphere.
He said: “Since there are few species which have physical, chemical and spectral properties that are consistent with the composition of the Venus clouds, they may have evolved independently on Venus.”
He noted the possibility that liquid water may have remained on Venus for up to two billion years.
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And erupting volcanoes and hydrothermal vents may also have existed.
Dr Limaye added: “If similar conditions elsewhere led to the evolution of life, why not on Venus?”
Dr Emilie Royer, a Planetary Science Institute research scientist who was not involved in the study, confirmed no proposed theory about the absorbers has yet fully explained them.
She said: “This new result is very important because every piece of information we obtain from atmospheric levels from the upper clouds and above will help resolve the enigma” of the planet’s mysterious atmosphere.”