Recently, researchers published a paper in the journal Nature-Astronomy that they found phosphine (PH3) in the atmosphere of Venus. This gas is considered a potential “sign of life.” Many people were shocked by the news. This discovery will undoubtedly reawaken the scientific community’s interest in Venus. So, what will happen in the future for this nearest planetary neighbor? How will scientists determine whether there is life in the clouds of Venus?
Phosphine is a flammable gas, usually associated with the odor of swamps and the droppings of animals such as penguins. Generally speaking, phosphine is not the focus of astrobiologists when searching for extraterrestrial life. However, the publication of this new paper changed the situation.
Phosphine consists of one phosphorus atom plus three hydrogen atoms. On the earth, the gas is mainly produced by microorganisms that can grow in an oxygen-deficient environment . Considering that the environmental conditions of Venus are too harsh for life, it is a huge surprise to be able to find about 20ppb of phosphine on this planet. In theory, phosphine gas should have been completely eliminated due to the large amount of ultraviolet radiation and the rich sulfuric acid in the clouds of Venus. Something on Venus seems to be constantly producing phosphine. What will it be?
Astronomer Jan Greaves of Cardiff University in the UK is one of the authors of this new study. He pointed out that the analysis results have certain limitations, and this new study cannot be used as evidence of the existence of life on Venus. But the researchers also said that phosphine may indeed be produced by some unknown chemical process or by life itself.
Venus is not the main target of astrobiologists, because its surface temperature is around 450 degrees Celsius, and the pressure exerted by the atmosphere is 90 times that of the pressure we feel on Earth. If there is life on Venus, it will force us to seriously rethink the habitability of planets, whether it is planets within the solar system or exoplanets.
Although Venus is the closest planet to the earth, astronomers know very little about it, and some of the reasons for this are completely understandable. Historically, Venus has not been considered an attractive target when formulating costly scientific missions, while other planets, such as Mars, have received high attention.
“In the past 20 years, we have made some new discoveries, and these new discoveries mean that the possibility of discovering life on other planets has greatly increased,” a NASA spokesperson explained in a statement. As the number of planetary bodies is increasing, it turns out that Venus is an exciting place to discover, although it has not been an important part of the search for extraterrestrial life due to its extreme temperature, atmospheric composition and other factors.”
Therefore, scientists currently do not fully understand the surface topography, geology (including its geological history), structure and potential volcanic activity of Venus. However, after the discovery of phosphine on Venus, NASA Administrator Jim Bridenstine stated on social media that this was “the most important development in finding evidence of life outside the Earth” and believed that “it is time to prioritize Venus is now”.
There is still a lot of work to be done on Earth before we launch a new probe to Venus for investigation. First, scientists need to confirm whether these phosphine wavelength signals are true and reliable. Greaves and his colleagues collected these signals using the James Clark Maxwell telescope in Hawaii and the Atacama large millimeter wave array in Chile.
“First, you should search for phosphine signals at other wavelengths to confirm the test results, and at the same time map the global distribution of phosphine on Venus,” explained Sanjay Limayer, a scientist at the University of Wisconsin-Madison. This is not easy, because the content of phosphine in the ultraviolet and infrared bands is relatively small, and its spectral characteristics may be masked by the characteristics of more abundant chemical substances, such as carbon dioxide, water vapor, sulfuric acid and so on.”
Limayer said that as an inner planet, Venus will never be too far from the sun in the sky, which makes observations at certain wavelengths difficult. Fortunately, radio observation does not have this problem. He pointed out that in addition to searching for specific biological gases, scientists should also look for identifiable contrast features in the atmosphere of Venus and try to track the evolution and chemical properties of these features.
Two years ago, Limayer led a study that suggested that the contrast in the form of dark spots may be a sign of life on Venus, and that the atmosphere of Venus may be able to accommodate microorganisms. At the time, this seemed to be a weird idea, but today, the situation seems to have turned around.
Ultimately, scientists hope to launch probes to Venus in the future. The good news is that, as explained in NASA’s statement, two of the next four candidate missions in the agency’s Discovery Program—VERITAS and DAVINCI+—are related to Venus. The same is true for the EnVision mission of NASA’s partner, the European Space Agency (ESA). Since Venus is very close to the earth, it may be possible to explore in a more gentle way.
“DAVINCI+” is the abbreviation of “Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging Plus” (Venus deep atmosphere noble gases, chemical and imaging detection +), where “+” refers to the mission’s imaging components. This is a probe with a parachute that can slowly descend to the surface of Venus. Using the various instruments it carries, DAVINCI+ can detect a variety of gases and map the surface of Venus. ,
The name of the “VERITAS” mission is derived from the “Venus Emissivity” (Venus Emissivity), “Radio Science” (Radio Science), “Interferometric Radar” (InSAR), “Topography” (Topography) and “Spectroscopy” An acronym that includes a satellite orbiting Venus. In addition to drawing a three-dimensional topographic map of Venus, the probe will also measure the temperature of Venus, study its gravitational field, conduct some remote geological studies, and deploy a probe equipped with a mass spectrometer to detect chemical features.
The ESA EnVision mission is a satellite that mainly studies the geology of Venus, but given its impressive sensor array, the probe can also be used for many other missions.
There are also private companies considering exploring Venus, such as the mission to Venus proposed by the founder of the aerospace company Rocket Lab and New Zealand engineer Peter Baker. According to Baker’s plan, a probe equipped with multiple instruments will be launched into the atmosphere of Venus. At a press conference held recently, Greaves said that her team is willing to cooperate with private companies.
It should be noted that these tasks have not yet been approved, but the discovery of phosphine has attracted the attention of countless people overnight. Once these probes are in place, scientists should be able to sample the clouds about 47 to 70 kilometers above the surface of Venus. Limaye called these investigations “necessary.” He explained that by measuring in the clouds, scientists “should be able to detect the presence of any important biological gas, not just phosphine, but also methane and other gases.” He believes that another useful task is to identify “microbes”. What are the physical, chemical, and biological properties of the cloud droplets that depend on it for survival?” Of course, the premise of this mission is that microorganisms do exist in the clouds of Venus.
Limayer added that semi-floating platforms, such as Northrop Grumman’s “Venus Atmospheric Maneuvering Platform” (VAMP), would be the ideal place to complete this task, because the platform can be equipped with microscopes and spectroscopy. Meter and other instruments. Another option is the balloon, similar to the Soviet Vega program mission in the mid-1980s. “We hope to see something like this again,” Sarah Siegel, an astrobiologist at the Massachusetts Institute of Technology and co-author of the new study, said at a press conference. “Maybe it’s the super The version can continue to run for a week to a few months, or even a few years, not just a few days.”
Siegel described the balloon as an “excellent way” to study the atmosphere of Venus for the same reasons as Limaye emphasized. However, the maneuverability of balloons is far less than that of VAMP or similar aircraft, such as the stingray glider proposed by some scientists, called “BREEZE”.
Some scientists have proposed that a stingray glider (called “BREEZE”, imaginary map) can be used to detect the atmosphere of Venus
Limayer and Siegel both stated that the airborne spectrometer is critical to the mission of exploring the atmosphere of Venus. “Using a spectrometer to work at different wavelengths (from ultraviolet to millimeter wave bands), it should be possible to map the distribution of phosphine, sulfur dioxide and other gases to see if they are related to the cloud cover contrast characteristics on the Venus image,” Lima Ye explained.
As Limayer and colleagues pointed out in a 2018 paper, these detections can allow scientists to understand the connection between possible life forms and contrast features in the atmosphere of Venus. He pointed out that other important equipment of the atmospheric probe will include meteorological sensors for collecting environmental data, chemical sensors for studying the composition of planetary atmospheres, fluorescence imaging microscopes for physical and biological characterization, and other biological features that can be detected. sensor. For the orbiting satellites of Venus, Limayeur recommends the use of multispectral imaging cameras and spectrometers.
In addition to these items, astronomers also need to figure out what strange non-biological or biochemical processes may exist in the atmosphere of Venus. On Saturn and Jupiter, phosphine is naturally produced through abiotic processes, but there is no similar situation on Venus. Perhaps as this new study shows, scientists have some issues that have not yet been considered. Computer algorithms that can mix and match atomic combinations may be helpful.
At the same time, biologists should also figure out how extremophiles can withstand the harsh conditions in Venus’ atmosphere. As Greaves explained at the press conference, “The real challenge is to observe whether any form of life can evolve and adapt to this incredibly acidic environment”, because there is no similar environment on Earth. Simply put, this hypothetical life form may actually be evolutionary or biologically impossible.
Indeed, it’s time for scientists to start multidisciplinary cooperation, because this work requires astronomers, engineers, astrobiologists, microbiologists, chemists, geologists, computer scientists, planetary scientists, and other experts. Work together. On the other hand, we also need to consider some other issues, such as what are the ethical and safety considerations for studying these microorganisms? What should we do if we accidentally contaminate Venus with bacteria on the earth in our rush to search for life? Of course, all data must be carefully reviewed, confirmed and verified before scientists can draw clear conclusions.
No one can say that we will find extraterrestrial life soon, and this process is not easy, but given that there may be some tiny extraterrestrial creatures on the nearest planet, it may be time to start taking this seriously Problem.