Is there Life on Venus?

Venus may be our sister planet, but we have all heard of its hellish conditions. From raging temperatures (reaching 867 F), to thick sulfuric acid clouds, it is hard to conceive of life existing there. Yet research into Earth's extremophiles--microorganisms that can thrive in extreme environments where most forms of life cannot, such as hydrothermal vents far beneath the ocean's surface or near volcano outflows--tells us something about life's variability and ability to adapt. According to some scientists, including planetary scientist David Grinspoon, microbial life may still exist on Venus, not on the surface, but in the clouds--and samples of this life may have visited Earth.

It is generally agreed upon that in the distant past, Venus had large, warm oceans, where life potentially had approximately two billion years to evolve. The next chapter in its planetary story is one you might be familiar with: a rogue greenhouse effect, taken to its extreme, leading to the gradual evaporation of its oceans and its present hell-like conditions. Any microbial life forms which may have existed may have had enough time to adapt to the new conditions and migrate towards the clouds. The sulfur present in the atmosphere may even be utilized by microbes to help resist the effects of the intense life-killing UV radiation. The clouds are thought to be mostly uninhabitable, with temperatures at the base reaching 206F, and negative 46F at the top. There is, however, a band in the middle of the atmosphere that is actually at a rare Earth-like room-temperature. Unlike the clouds of Earth, these Venusian clouds are much thicker and more stable, with dust particles able to float for months at a time instead of a few days. This is perhaps sufficient time to be biologically sustainable enough for microbes to reproduce. Certainly not an ideal locale for the aspiring biologist hoping for a hands-on experience!

Now, how does one make the leap from the possibility of life existing on Venus to this idea of life being carried across the vast distances of space? The Cardiff Centre for Astrobiology, armed with data from the European Space Agency's Venus Express probe, has a two-word answer: solar wind.


 The Cardiff center claims that Venus's clouds contain chemicals very similar to those in which microorganisms can be found on Earth, and that any life could be blown away from the atmosphere. Solar wind, the stream of charged particles constantly emitted by the sun, is constantly tearing at Venus's surface much more ferociously than it teaser at Earth's, as we have a protective magnetosphere, and this wind could carry some of Venus's ions from its upper-atmosphere with it. Earth is downstream relative to Venus, and if correctly positioned (a rare occurrence), Professor Chandra Wickramasinghe and Dr. Janaki Wickramasinghe (from the Cardiff center of Astrobiology) believe bits of the Venusian atmosphere, including some of its naturally hardy, UV-resistant microbial life, may periodically visit Earth. Thus, in addition to being geologically similar, Earth and Venus may be biologically connected too. Is there anyway to confirm this, a way to detect such life? Not at the moment, it seems.

While it is a fascinatingly provocative idea, it is not universally agreed upon in the astrobiological and planetary science community. Some, such as Professor Fred Taylor, a planetary scientist at Oxford University, say that the whole notion of life existing in Earth-like portions of Venusian clouds is not very likely in the first place. Either way, further evidence and research is needed to settle whether this interplanetary immigration occurs at all. If it really is possible, then it may shed light onto our own incredible origins as organisms. Perhaps NASA could send in a floating probe and then ship off the samples back to Earth. That's certainly worth a trip around the cosmic corner, don't you think?

Note: the topic of life from space is an inherently fascinating topic, one that deserves to be written about in much more detail! Readers, stay-tuned!

Image credit
Figure 1 (top): Image processing by R. Nunes (Via Astrosurf)
Figure 2: C. Carreau (Via ESA)

For further reading:

1. "Could UV-Adapted Microbial Life Exist in the Atmosphere of Venus?" Daily Galaxy. (2011).

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2. "Life from Venus Blown to Earth?". BBC. (2008).

3. Gugliotta, G. "Scientists Make Their Case for Seeking Life on Venus". Houston Chronicle. (2004)