What does NASA say about extraterrestrials

astronomy Notes on extraterrestrial life on Venus

Venus is not the type of planet to look for aliens in the first place. It is over 400 degrees hot on its surface. There is a crushing pressure of around 90 bar on the floor. The Venusian atmosphere consists of 95 percent of the greenhouse gas carbon dioxide and the clouds of Venus consist of droplets of corrosive sulfuric acid.

Is there life in the high cloud layers of Venus?

But it is precisely there, in the high layers of the cloud, that life forms could be hiding. At an altitude of 50 kilometers, the temperature is only a pleasant 30 degrees. The pressure is 1 bar, so it is similar to the air pressure on the earth's surface.

“When we saw the first signs of phosphine in the Venusian atmosphere in the measurement results, it was a shock for us” - says Jane Greaves, astrobiologist at Cardiff University and head of the international research team that measures measurements in the atmosphere of our neighboring planet has made and has come to a sensational result.

According to this team, there is a clear indication of extraterrestrial life on Venus: the gas phosphine.

Phosphine is only produced under certain conditions

Two teams independently discovered phosphine in these high-lying cloud layers using radio telescopes. This gas cannot easily arise in nature. It consists of a phosphorus atom to which three hydrogen atoms are bonded.

In an atmosphere in which there is unbound oxygen, such a molecule does not come about because the phosphorus reacts much faster with the oxygen than with the hydrogen. On earth, phosphine can therefore only be produced in places where no free oxygen is involved in the chemistry - in the subsurface of bogs, for example.

Phosphine as a possible indicator of life

Phosphine has also been found in the intestines of fish. And in the droppings of penguins. Basically, however, phosphine is a strong poison for living things that depend on oxygen. Conversely, however, it can be an important part of their metabolism for living beings whose metabolism does not require oxygen. When looking for life on planets without an oxygen atmosphere, phosphine is therefore seen by astrobiologists as a strong biomarker.

Look for typical chemical processes

Astrobiologists try to discover extraterrestrial life by looking for the chemical processes that are typical for it. Each planet reflects the radiation from its star - but the composition of the reflected light depends on which gases are in the planet's atmosphere. Depending on the gas mix in the planet's atmosphere, certain wavelengths are reflected, others are absorbed.

In the case of phosphine, research in recent years has made it clear which wavelengths of electromagnetic radiation are typically absorbed by this molecule. The result: Typical for phosphine is an absorption of radiation in the range of very short-wave radio radiation.

Search for the origin of phosphine

In June 2017, the James Clerk Maxwell Telescope in Hawaii first directed its radio antenna at Venus and promptly came across phosphine in the Venus clouds. However, the scientists remained skeptical of the result. They began to examine all the ways in which phosphine could be produced on Venus without the assistance of alien microbes: lightning in the atmosphere, volcanic eruptions, the chemical reaction of thrown up minerals with the sulfuric acid of the clouds.

But the computer simulations showed: In this way, no more than a ten-thousandth of the amount of phosphine that had been discovered in the radio light of Venus could be produced. In March 2019, measurements with the ALMA telescope network of the European Southern Observatory in Chile confirmed the surprisingly large occurrence of phosphine in the Venus clouds.

Dark spots in the clouds of Venus

For decades, astronomers have been wondering about inexplicable, constantly changing dark spots in the clouds of Venus that appear when the planet's cloud cover is viewed in the range of UV light. This phenomenon has already fueled speculations about microorganisms floating in the clouds of Venus.

But a break-proof chain of indicators cannot yet be linked from the dark spots and the measurement of phosphine. The atmosphere of Venus has not yet been researched enough for another surprising explanation for the occurrence of phosphine to emerge.
If Venus microbes actually exist, they must have found an extremely ingenious way to deal with up to 90% sulfuric acid content in the cloud droplets of Venus.

For terrestrial microbes, an acid content of more than 5% is fatal. In addition, the cloud droplets tend to get larger over time and sink into the deeper, hot cloud layers of Venus and evaporate there. But astrobiologists could imagine that this is even an integral part of the life cycle of the Venus organisms. As they dry out, they could form spores that are carried up by updrafts to develop into new microbes.

Space probes to Venus planned

What is actually going on in the clouds of Venus can only be determined by space probes. Russia plans to continue the traditional series of its Venus flights between 2026 or 2031. The Venera-D probe could then also release a balloon or solar-powered aircraft into the upper atmosphere of Venus to see whether the Venus microbes actually exist. NASA has appropriate concepts and Russia would be interested in working together.