Astronomers have discovered a rare element - phosphine - in the clouds of the planet Venus. On Earth, this gas is only produced in industry or it is emitted by bacteria living in an oxygen-limited environment
[Translation by Dr. Nachmani Moshe]
Astronomers have discovered a rare element - phosphine - in the clouds of the planet Venus. On Earth, this gas is only produced in industry or it is emitted by bacteria living in an oxygen-limited environment
An international team of astronomers announced a long time ago the discovery of a rare element - phosphine - in the clouds of the planet Venus. On Earth, this gas is only produced in industry or it is emitted by bacteria living in an oxygen-limited environment. Astronomers have speculated for decades that the high clouds above the planet Venus could provide a home for bacteria. "When we saw the first hints of the presence of phosphine in the spectrum of Venus, it was a shock!" said research team leader Jane Greaves of Cardiff University in the UK, the first team to ever observe the phosphine spectrum in space. Verification of their discovery required the use of forty-five antennas as part of an advanced telescope located in Chile. The telescope observed Venus at a wavelength of only about one millimeter, a wavelength much longer than the eye can observe - a wavelength that only a high-altitude telescope can do effectively.
The international team, which includes researchers from Britain, the US and Japan, estimates that phosphine exists in the clouds of Venus in a low concentration, only about twenty parts per billion parts. Following these observations, the researchers ran calculations to see if such amounts could be due to natural non-biological processes occurring on the planet. Some of the solutions to this research question include, among other things, the sun's rays, minerals emitted into the air from the surface of the star, volcanoes, or lightning, but none of these factors can create such an amount. From the calculations it was found that these non-biological sources could create at most ten thousandths of the amount observed by the telescope.
In order to create the amount of phosphine (composed of hydrogen and phosphorus) observed on the surface of Venus, extraterrestrial organisms would have had to operate at only one-tenth of their production capacity, according to the researchers. Bacteria on Earth are known to be capable of creating phosphine: they feed on the yeast found in minerals in the soil, or in biological material, add hydrogen and eventually emit phosphine. Any organism found on Venus will likely be very different from its counterpart on Earth, but it too may be a source of phosphine in the atmosphere.
Although the discovery of phosphine in the clouds of Venus came as a surprise, the researchers are confident of their discovery. "Fortunately for us, the conditions at the observatory were good for tracking when Venus was still at a suitable angle to Earth. At the end of a complex processing process, the researchers realized that their observations were accurate - a weak absorption of the wavelength corresponding to the phosphine gas, when the particles are illuminated against the background of the warmer clouds below them," says the lead researcher. The research findings were published on September 14, 2020 in the scientific journal Nature Astronomy.
Another scientist in the research team previously investigated the potential of phosphine gas as a "biological signature" of living beings that exist in an oxygen-absent or limited environment on planets around other stars, since normal chemistry produces only tiny amounts of oxygen there. The researcher explains: "Finding phosphine in Venus was an unexpected bonus! The discovery raises many questions, such as how any organism can exist in the conditions of Venus. On the surface of the earth there are bacteria that are able to survive in environments containing five percent acid - but the clouds of Venus are made almost entirely of acid." The research team believes that its discovery is significant in light of the fact that the researchers can rule out many alternative ways of producing phosphine, but they acknowledge that verifying the possibility of 'life' still requires much further research. Although the high clouds of Venus have temperatures of up to thirty degrees Celsius, they are extremely acidic - close to ninety percent sulfuric acid - a serious challenge to the ability of any species of bacteria to survive.
If it is proven that the source is biological - it will be a revolution in astrobiology
One of the researchers explains: "The possibility of phosphine production in Venus from a non-biological source is unlikely following our existing insights into phosphine chemistry in the atmospheres of rocky stars. Verifying the existence of life in the atmosphere of Venus will be a significant breakthrough in the field of astrobiology; Therefore, it is necessary to advance these fascinating findings with the help of theoretical and observational experiments in order to disprove the possibility that phosphine on rocky stars may come from a different chemical source than that on Earth." Further observations of Venus and rocky stars outside our solar system may help gather clues as to how phosphine can be produced in them and contribute to the search for signs of extraterrestrial life.
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