Thursday, October 29, 2020
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How many lives are needed to generate a phosphine signal on Venus? – haveeruonline

By Staff , in Biofuels , at September 21, 2020

How many lives are needed to generate a phosphine signal on Venus?

Biometric signature

last week, There was an amazing announcement About the search for extraterrestrial life: Phosphine gas detected in Venus’ cloud-a potential indicator of life or “biosignature”. Now, some gases can be false positives for biosignatures because they can be produced by other chemical processes on the planet, such as photochemical processes in the atmosphere or geological processes below the surface that produce a given gas. For example, methane could be a biosignature. We hunted it on MarsHowever, we know that methane can also be produced geologically. It’s really amazing to find the phosphine in the Venus cloud. This is because we don’t currently know how to generate phosphine abiotic or without life being part of the equation. The question is-how much life ??

Venus Clouds Seen From Mariner 10’s Airship-NASA

“Possibility”

If a biological signature is found, the way to rule out false positives is to look at the concentration of that gas and see if a plausible amount of life can produce the gas. Phosphine gas in the Venus cloud was detected at a concentration of 20 ppb (1 billionth). If the biomass required to produce this concentration of gas is high, an unfamiliar abiotic process may still be working. Venus may have life, but in a world where it is generally thought that it has no surface habitability, demanding high life in a world begins to lower the alien credibility.

Past research has already reviewed calculating the biomass required to determine how plausible it is that a bio-specific gas is actually a by-product of living things rather than another unknown abiotic process. 2013 Seager, Bains, Hu Most of the ET hunts published their studies with the foresight that atmospheric chemistry is likely to investigate distant extraterrestrial atmospheres to determine if something is a sign to us that something lives there. One such signal is a chemical out of balance. It is an excess of gases or certain gases that should not coexist. For example, if someone is looking at our planet from a distance of light years, they will find that the oxygen concentration in our atmosphere is 10 times higher than for chemical balance. The imbalance is what life on Earth creates and adds to the atmosphere. We are aware of other abiotic processes that can account for that degree of imbalance. Another sign is the presence of gases that have no known source other than living things. That’s where the phosphine comes into play. If there are no other known processes Dr. Sarah Seeger Her team explored “whether biosignature gases can be produced by physically plausible biomass.” And we don’t know exactly what extraterrestrial organisms are, but we do know that some chemical and physical processes are universal. Only a lot of energy can be obtained from certain chemical reactions. So, this study used these universal principles to avoid the trap of “terrain centrality” that is based on all biological models of life as we know it on Earth.

Looking through Venus’ clouds to see the surface using radar-NASA

Based on the same model as Dr. Sara Seager and the team above, New research by Mansavi Lingam and Abraham Loeb Released on September 16th.Work We applied the model to the recently discovered phosphine on Venus. result?

“We found that the typical biomass density predicted by our simple model is several times lower than the average biomass density in Earth’s aerial biosphere.” – Lingam and Loeb 2020

In other words, the amount of life that has to live in the clouds of Venus in order to produce the level of phosphine we sense is far less than the amount of life that lives in the clouds of our planet, that is, a plausible amount of life. It’s really interesting because it means we can still count life as a possible source of phosphine gas. It tells us that there are as few living things as possible that emit the signals we see on Earth. If the amount of biomass you need is really high, you may have to look for other abiotic processes that we don’t know about because it’s unlikely there will be high concentrations of life on Venus.

Earth’s clouds/atmosphere also support the aerial biosphere
– Shebandowan Lake Sunset, Ontario – C. Matthew Cimone

Life in the clouds

Now we come to the interesting part of guessing what kind of creature can produce phosphine. 1967 year, Great science communicator and astronomer Carl Sagan, and biophysicist Harold Morotwitz speculated about life in the clouds of Venus. for First few billion years In history, Venus may have been better suited to life over the past billion years to become the Venus we are familiar with. Life not only has time to evolve on the surface, but can also migrate to clouds. Surrounded by clouds and a very dense atmosphere, Venus’ surface is slightly uncomfortable at 460 degrees Celsius and hot enough to melt lead. The “cold” days of Venus Lead frost. So the surface is lifeless. But clouds are a different story. In clouds 50 km above the surface of Venus, the temperature drops to about 5 C, and water droplets can form. “It’s never been difficult to imagine indigenous biology,” said Sagan. Sagan and Morowitz envisioned a “floating bladder” about 4 cm in diameter carrying hydrogen bubbles inside to keep it high.

Venera’s surface of Mars 13. In harsh conditions, the probe survived for only two hours and was enough to transfer just one of the few pictures taken from the surface of Venus-Roscomos via NASA.

However, modern research suggests that microbial life may be more suitable for the Venus cloud. Dr. Sarah Seeger’s Research Predicts Microorganisms Present in water droplets Because “the requirement for a liquid environment is one of the common properties of all living things, regardless of their biochemical composition”. The problem is that when the water droplets become large enough, they settle to a low altitude that falls to a destructive temperature. The life cycle of these microorganisms depends on the condition of “small, dried spores and cells that inhabit larger, metabolically active droplets”. Thus, the proposed microorganism lives in nutrient-rich droplets. The water condenses, but precipitates and evaporates at a cloud level as low as 33-48 km, drying the microorganisms. In the dry state, it is lifted by the wind that returns the microorganisms to a higher altitude and rehydrates in a new drip house. And within one drop, it potentially produces phosphine during the time of the microbial’s metabolic activity.

I would never have seen this coming. In my imagination, Mars will be first. I’ve spent many planetarium shows as we fly through the solar system in a fictional quest for life outside of Earth, and it always made Venus shine “probably too hot”. Nonetheless, one of the best biometric signatures for life comes from this hellish world. But it’s science! We’ll guess, test, learn, and probably discover more amazing things than we could have imagined (I’m still cheering on Float Bladder. # Tim Venus Float Bladders)

Learn more:

Biomass required to produce phosphine detected in Venus’ cloud deck – Lingam and Loeb 2020

Phosphine Gas on Venus’ Cloud Deck – Nature

Phosphine detected in Venus’ atmosphere-a possible indicator of life? – Astrophysical biology

Have scientists discovered signs of life on Venus? – The universe today

What’s on Venus’ Surface: The History of the Venera Program” – Universe Today Video

Life in the clouds of Venus? Sagan and Morowitz 1967-Nature

Venusian Lower Atmosphere Haze as Repository for Desiccated Microbial Life – Seager at al 2020

Biomass-based model for estimating the feasibility of extraterrestrial biosignature gases-Seager, Bains and Hu 2013