I will imagine you Venus tonight and pray, pray, pray to your star like a Heathen. – John Keats
Venus, visible in the night sky above Salgotarjan, Hungary, in March, is typically the brightest object in the night sky other than the moon. Credit…Peter Komka/EPA, via Shutterstock
The brightest star on a night sky that is visible from Earth is planet Venus. It has been a planet that has held immense interest to scientists and researchers who study the solar system. In the ancient times, people thought Venus was two different objects – the Morning Star and the Evening Star. The planet is named after Venus, the Roman goddess of love and beauty. “After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of -4.6, bright enough to cast shadows. Because Venus is an interior planet from Earth, it never appears to venture far from the Sun: Venus reaches its maximum brightness shortly before sunrise or shortly after sunset, for which reason it has been known as the Morning Star or Evening Star.” Venus is about the same size of the Earth. It is classified as a terrestrial planet and it is sometimes called Earth’s “sister planet” due to the similar size, gravity, and bulk composition. The hopes have been high for it being the second source of light. “Venus is covered with an opaque layer of highly reflective clouds of sulfuric acid, preventing its surface from being seen from space in visible light. Venus has the densest atmosphere of all the terrestrial planets in our solar system, consisting mostly of carbon dioxide.”
[On Monday (Sep 14), scientific research was published showing phosphine, a possible signature of life, present in the atmosphere of Venus. The following is NASA’s announcement related to this discovery.] The team of researchers was led by Jane S. Greaves of Cardiff University.
A paper about chemistry on Venus was recently published in Nature Astronomy. NASA was not involved in the research and cannot comment directly on the findings; however, we trust in the scientific peer review process and look forward to the robust discussion that will follow its publication.
According to the Washington Post, the researchers made it clear “this is not a direct detection of life on Venus.” Phosphine, a foul smelling toxic gas made up of one phosphorus and three hydrogen atoms (PH3) was discovered in the middle layer of the Venus atmosphere. “If phosphine really does exist in Venus in the quantity reported (concentration up to 20 parts per billion), we stand to learn something more profound. Clever chemists will now be trying to come up with alternative, no biological sources that produce phosphine in sufficient amounts. If they succeed, we learn something new, perhaps something important; about Venus and other planets…The hopes had been high for it being the second source of life in the solar system. “– Scientific American
There is no carbon cycle on Venus. As a result, carbon does not get locked into rocks. “It does not have any organic life to absorb it in biomass.” The speculation is: in the primordial times the oceans on Venus evaporated as the temperature went up.
The surface of the planet is dusty and dry with plenty of rocks. There are volcanic activities which add to the rock formations. The water very possibly dissociated as well. Scientists believe there is no magnetic field on Venus like Earth.
Because of the lack of a planetary magnetic field, the hydrogen must have gone into interplanetary space by the solar wind. “The atmospheric pressure at the planet’s surface is 92 times that of the Earth.”
According to National Public Radio’s Nell Greenfieldboyce, “All in all, it seems like an unlikely place for life. Nonetheless, the new report in the journal Nature Astronomy has astrobiologists and planetary scientists talking. Two different telescopes, at two different times, looked at Venus and saw the chemical signature that is unique to phosphine. If this gas is there, Venus has either got geologic or chemical activity going on that no one understands, or alien life might be living right next door.”
The data is not conclusive yet. The signature can be a false signal. As in all of science, this needs to be independently verified, or refuted by other scientists. The chemical is not easy to manufacture, and the molecule should have been destroyed in the clouds of the planet. And yet it was detected by two groups. Does this mean life exists on this sister planet?
It is too soon to tell. Is the result real? Scientists scratch their heads and will try to ‘falsify’ the findings. The hypothesis must be tested and if possible, proven false. Could the discovering scientists have made an error in data processing? Could this be a false signal?
If the tests stand all scrutiny by other scientists, there are still two possibilities – that there is some unknown geological or chemical process going on in the planet that we do not understand, or that life-forms exist that can combine Phosphorus and Hydrogen on Venus as it can on the planet Earth.
If the experiment fails, the scientists will be motivated to do extensive studies to learn about the atmosphere of Venus. After failures there are always some possibilities of finding definitive evidence whether there is life on Venus or on other planets. By studying the planets, the scientists’ findings one day may very well indicate that there is extraterrestrial life on other planets. Such studies will reveal one such planet’s potential to harbor life and whether its conditions would actually support life. Most may not be life as we know it.
Is Venus habitable? Where do we go from here? It is an exciting discovery, and we should continue searching, perhaps from a closer distance? Is it an unknown geochemical process, or a possible sign of life? Can they confirm such findings? We should send another sample-returning mission to the sister planet. The last such mission was in 1989. Several such missions are being discussed. A smaller NASA mission under consideration, DAVINCI+ proposes to study the deep atmosphere of Venus. If selected, it will be launched in 2021 for further explorations of extrasolar planetary systems. The announcement of September 14 will now push NASA and other “space agencies to take a closer look at Venus.”
Venus has long been ignored because of its atmosphere and close proximity to the sun. It might be the next planet to answer the oldest question if there are others like ourselves out there. Besides NASA, the European Space Agency (ESA) and the Russians are also interested in exploring the possibility of life on other planets. If such a discovery is made, it will profoundly change our view of the Universe.
Bottom line: On September 14, 2020, Venus was added to the list of potentially habitable worlds in the solar system. Phosphine, a toxic gas commonly produced by organic life forms but otherwise difficult to make on rocky planets, was discovered in the Venus atmosphere. Either there is some sort of life in the Venus clouds, generating phosphine, or there is unexplained and unexpected chemistry taking place there. How do we find out which it is?
The possibilities are wide open at this point. Perhaps innovative American poet E.E. Cummings said it best: “listen: there’s a hell of a good universe next door; let’s go.”
Postscript: I have long been fascinated by questions like what is beyond the Earth and what the other planets in our solar system are like. Does life exist elsewhere in the solar system? The above article deals with such a possibility. In writing this short article about the possibility of life on Venus, I have consulted a former NASA research scientist about the technical and scientific terms. The discussion helped me understand the excitement in the scientific community better. The enthusiasm by NASA Administrator Jim Bridenstine shows that it will continue to absorb our attention for years to come.
Zeenat Khan writes from Maryland, USA.