Astrobiology

A Discipline in Search of a Subject

With the successful arrival of NASA’s Perseverance rover on Mars this past February, media around the world have been trumpeting one of the exploratory robot’s chief missions as one of profound importance and philosophical importance: searching for traces of life, past or present, on the Red Planet.

The attempt to find microbial or macrobial life was the overriding criterion used in deciding where to land the rover. The chosen site, the Jezero crater, is thought by Mars specialists to have once been a lake bed.

This staggering technical achievement and its motivation immediately became the subject of keen international press attention, and the sample of accounts from the international press in Germany, the Netherlands, India, and Israel all mention the search for signs of extraterrestrial biological life as the most important component of the mission.

This is unsurprising, since of the question of the possible existence of extraterrestrial life is a surefire draw for the public. National Geographic, The Guardian, the German Spektrum News (a natural science magazine), het Reformatorisch Dagblad, and every one of the scores of sources consulted for this article, mentioned the role that the Perseverance is hoped to play in answering the question “Are we alone in the universe?” Spektrum’s editorial makes this clear:

"You’re supposed to think that this [technical achievement] is enough. But the mission is supposed to achieve much more: With the help of the samples collected by “Perseverance”, the intent is to prove at long last that extraterrestrial life once developed on Mars. NASA emphasizes this prospect at every opportunity- a sort of interplanetary carrot with which the space agency aims to make the costly journey to Mars more appealing to the general public."

The editorial goes on to comment:

"Martian microbes and Mars colonies are fantastic visions that draw a lot of people in, but both are simply wishful thinking. Yes, there once were great quantities of liquid water on Mars, that much is shown already by the river valleys that cut channels into its surface. But whether the planet really was as Earth-like 3.5 billion years ago as NASA suggests, is an open question. Climate simulations of that period speak against it. According to them, Mars, even in its infancy, was covered by a sheet of ice that was kilometers thick. Water would have to flown mainly out form under glaciers, such as after volcanic eruptions or meteorite impacts."^[1]

This entry from the German press is sober and matter-of-fact, compared to the much coverage of the Perseverance mission in the American press. Spektrum’s editors are less than convinced of the possibility of discovering signs of past or present life on Mars, and a bit critical of their American colleague’s making the search for such signs a part of nearly every press release relating to the mission. The climate simulations speak against a life-friendly environment in the past, the radiation bombarding the surface of the red planet is certainly lethal to life on the surface today, and even that surface presents some considerable problems for life. A summary of research presented on the website of the Astrobiology Society of Britain states the matter clearly:

"The ASB’s Jennifer Wadsworth, along with Charles Cockell, at the UK Centre for Astrobiology have found that the surface of Mars may be even less hospitable than previously thought. When they exposed perchlorates (common compounds on the Martian surface) to high levels of ultraviolet (UV) radiation similar to the flux at the surface of Mars, they became bacteriocidal. This suggests that the surface of Mars would be even less suitable for life than previously thought. However, life may still find a home a few metres beneath the surface, where it would be shielded from UV radiation."[2]

The findings, Published in Scientific Reports, demonstrated that the chemistry of Martian soil alone had strong anti-bacterial qualities, qualities which were only multiplied when combined with the bacteria-killing effects of the ultraviolet radiation to which the surface is constantly exposed. The planet Mars has no magnetic field shielding its surface from solar or cosmic radiation. It has no magnetic field because it has no molten iron core to generate one, which fact also means it has no plate tectonics to drive a silicate-carbon cycle, which could not have gotten started anyway, if the climate simulations mentioned in the Spektrum article are correct, since the water would have been under miles-thick glaciers. Ergo…no life. These different elements in the structure of Earth’s crust and oceans interact and played vital roles in the history of life on Earth. Hugh Ross gave a good summary of the geological history:

"During Earth’s infancy, water covered the entirety of Earth’s surface and all Earth’s plates were made up of basalts (igneous rocks). Tectonic activity gave rise to plate subduction which resulted in some of the basalts being chemically transformed into silicates. Silicates are lighter than basalts and hence float above the basalts. Eventually, sufficient silicates formed for landmasses to begin appearing above the water’s surface.

The combination of Earth’s water cycle and the exposure of silicates above sea level initiated the silicate-carbonate cycle. Rain falling on the exposed silicates acted as a catalyst to generate chemical reactions, including a net reaction where carbon dioxide is removed from the atmosphere to transform silicates into carbonates and sand. The gradual removal of carbon dioxide, a greenhouse gas, from the atmosphere means that as the Sun gets progressively brighter (see figure) Earth’s atmosphere progressively traps less of the Sun’s heat. This compensation for the Sun’s brightening has allowed Earth’s surface temperature to remain suitable for life for a long time period. To word it differently, without an operating silicate-carbonate cycle, life could not remain on our planet for long."

The most relevant point for the search for extraterrestrial life is the importance of multiple interdependent atmospheric and geological factors in creating the conditions necessary to allow processes that are necessary to generate the precursors of the chemicals needed to generate the precursors of the chemicals needed to generate the basic ingredients of life.

Speaking of precursors for life, Mars is not the only planet that has been hyped as a new focus for research into astrobiology in recent months. Venus, too, ….no, I’m serious. Yes, that Venus. Yes, I mean the Inferno-scaped planet with the sulfuric acid atmosphere, surface temperatures hot enough to melt lead and atmospheric pressure at the surface 90 times that of Earth (or equivalent to pressure in the ocean at a depth of approximately 3,000 feet). In another exciting press release from NASA dated September 15^th, 2020, the public was alerted to the tantalizing prospect of a “biomarker” being detected in the Venusian atmosphere:

"Could there be life floating in the atmosphere of Venus? ….Venus' upper atmosphere may be sufficiently mild for tiny airborne microbes. This usually disfavored prospect took an unexpected upturn yesterday with the announcement of the discovery of Venusian phosphine. The chemical phosphine (PH3) is a considered a biomarker because it seems so hard to create from routine chemical processes thought to occur on or around a rocky world such as Venus -- but it is known to be created by microbial life on Earth….The phosphine finding, if confirmed, may set off renewed interest in searching for other indications of life floating high in the atmosphere of our Solar System's second planet out from the Sun." [3]

Capitalizing on the reported discovery, NASA administrator Jim Bridenstine went even further in a tweet published on September 14^th, 2020, calling phosphine “a byproduct of anaerobic biology”, labelling it “the most significant development yet in building the case for life off Earth” and saying “It's time to prioritize Venus."[4] The problems with that enthusiastic response to the possible discovery of phosphine are multiple. First, there is the fact that the observations cannot tell us anything about the source of the phosphine. It can be produced in volcanic eruptions and by lightning and Venus is known to have both.[5] Then there’s this telling phrase (in bold below)in a statement about the discovery made by the Royal Astronomical Society, a statement meant to address the question of possible contamination from Earth space probes sent to Venus:

"Very few organisms on Earth produce phosphine, and very few if any are capable of surviving in the extreme conditions in the Venusian cloud decks. This makes it highly unlikely that this is biological contamination from Earth." [6]

And that is the second and most significant problem for the “biomarker” assert: Few if any organisms can survive the extreme conditions in the Venusian atmosphere, and that would be just as true of any organism that could have evolved on Venus, if the right factors had been in place.

The number of these factors keeps multiplying, even at the starting point for any proposed scheme allowing organic chemicals to spontaneously organize into structures that might tend in a life-ward direction. If not destroyed by other chemical reactions in the minutes after they form. Or torn apart by UV radiation. These and other problems render spontaneous interactions of unintelligent, undirected causes poor candidates for the explanation of the origin of life, as award-winning synthetic chemist, T.T. and W.F. Chao Professor of Chemistry at Rice University, James M. Tour, has pointed out. He discusses the problems facing any realistic OOL scenario in a series of lectures recently published online with the title Introduction to Abiogenesis. It’s a 13-part series and deals with current and past research into origin of life chemistry in great detail. The key insight he conveys in this and his other work on abiogenesis can be summed up in the phrases “nature does not keep a lab journal” and “chemicals do not care about life”. In real life, as opposed to the fantasies of philosophical materialists looking for affirmation of the “molecules to man” myth, organic chemistry does not stop happening when it produces a necessary chemical component for a proto-cell. The chemistry keeps happening. What we are looking at on Mars and Venus are not signs of life, but signs of organic chemistry happening.

Nevertheless, if one were to judge from the hype surrounding the Venusian phosphine discovery and the Perseverance mission, one would think that the claims that NASA had photos showing fungi growing on Mars had been unanimously confirmed by the international scientific community. Studying fungus on another planet? That would be real “astrobiology”. However, that is precisely the opposite of the truth. There are no Martian fungi. Nor is there a 'Mars rat', its internet presence notwithstanding.

Astrobiology is, today, a discipline in search of a subject. There is no astrobiology happening. “Astro-Organic Chemistry” – though a real mouthful –would be an accurate description of the research that NASA is really undertaking on Mars right and that is being considered for future missions to Venus.

It’s not the case here that I see possible extraterrestrial life as any threat to a Christian worldview and thus am a priori predisposed to dismiss research in the field of “astrobiology” as pointless. As I have argued repeatedly over the years, Biblical theists, even Deists, have a better warrant for expecting there to be life elsewhere in the universe than philosophical materialists. What is called for here is a bit of dispassionate objectivity, German “Sachlichkeit”, about both the field and its findings to date. Sure, that would feed fewer hyped-up headlines, draw less attention on the internet, and perhaps make federal budget committees less likely to fund research in the field, but it would at least be honest.

NOTES

[1] For the original text, see: »Perseverance«: Hört auf mit den Marsmikroben! (spektrum.de). Translation by the author.

[2] News: The toxic surface of Mars | astrobiologysociety.org

[3] Source: Biomarker Phosphine Discovered in the Atmosphere of Venus | Science Mission Directorate (nasa.gov)

[4] Jim Bridenstine on Twitter: "Life on Venus? The discovery of phosphine, a byproduct of anaerobic biology, is the most significant development yet in building the case for life off Earth. About 10 years ago NASA discovered microbial life at 120,000ft in Earth’s upper atmosphere. It’s time to prioritize Venus." / Twitter

[5] On lightning: NASA - NASA Scientist Confirms Light Show on Venus; on volcanoes: Volcanism on Venus | Exploring the Planets | National Air and Space Museum (si.edu) and Volcanoes on Venus | Giant Shields and Extensive Lava Flows (geology.com)

[6] Venus phosphine detection factsheet | The Royal Astronomical Society (ras.ac.uk)