Physics, Earth & Space
Astrobiology Points to the “Miracle of Man”
In his new book The Miracle of Man: The Fine Tuning of Nature for Human Existence, biologist Michael Denton underscores the very special design woven into the cosmos and into nature that appeared to foresee biological creatures of our physiology. In the study of astrobiology, scientists are making observations that add to Denton’s case, further constraining the requirements for habitability.
Astrobiology differs from SETI in that it focuses on conditions for any life beyond Earth, even microbial life, rather than intelligent life. It is, according to the NASA Astrobiology Institute, “the study of the origin, evolution, distribution and future of life in the universe.” Though saturated with evolutionary dogma, research data from astrobiology can assist those building a case for the uniqueness of Earth. We wouldn’t know just how good we have it here on our planet without comparison studies.
Astrobiologists tend to “follow the water,” thinking that any place with liquid water is likely to have life or at least be a good place to look for it. That’s a half-truth, in that water is necessary, but not sufficient for life. Nevertheless, since water is (according to most origin-of-life researchers) a requirement for biology except in science fiction, that’s where they start. Our solar system has several bodies that have, or used to have, liquid water.
The second-innermost Galilean satellite of Jupiter is thought to have a large ocean of liquid water under its ice shell. It cannot be seen directly but is inferred from density measurements and from ice rafts in the crust that appear to have rotated and re-frozen. Possible plumes of vapor emanating from cracks have also been reported. UW News at the University of Washington tells about experiments to measure the properties of water in the extreme conditions of Europa and other icy satellites. Baptiste Journaux, a planetary science professor at the university, explains the project:
“We know that water supports life, but the major part of the oceans on these moons are likely below zero degrees Celsius and at pressures higher than anything experienced on Earth,” Journaux said. “We needed to know how cold an ocean can get before entirely freezing, including in its deepest abyss.”
The study focused on eutectics, or the lowest temperature that a salty solution can remain liquid before entirely freezing. Salt and water are one example — salty water remains liquid below the freezing temperature of pure water, one of the reasons people sprinkle salt on roads in winter to avoid the formation of ice. [Emphasis added.]
The research found that salty water could remain liquid at 300 Megapascals of pressure — three times that in Earth’s deepest ocean trench. With data in the bag from these measurements, scientists open to intelligent design could test the survival of Earth organisms in such conditions. Some microbes like Deinococcus radiodurans and small animals like tardigrades are known to survive high doses of radiation and pressure, and some halophytes survive in high salt concentrations (see the story on Death Valley’s desert pupfish at Phys.org). In California’s Mono Lake, brine flies and shrimp find the extreme salt comfortable at Earth pressures and temperatures. To determine if Europa’s conditions allow for habitation, scientists first have to measure what happens at the expected temperatures, pressures, and salinities there.
The origin of life, especially extremophiles, is another question, of course, but knowing the eutectic limits of water on other planets and moons gives ID researchers useful data for testing the habitability at Europa and similar locations. Astrobiologists tend to get giddy about life whenever liquid water might possibly exist. If it turns out that the most advanced living extremophiles cannot endure the conditions of pressure, temperature, and salt in Europa’s ocean, then it becomes highly implausible that life could have arisen there. Observational evidence is helpful in these discussions because it is inversely proportional to speculation.
C. S. Lewis’s novel Perelandra aside, hopes for life on Venus evaporated decades ago when the surface temperatures were found to be high enough to melt lead. A brief flap about life in the clouds turned out to result from a bad instrument reading. Still, scientists on both sides of the design issue can profit from knowing what happened at “Earth’s twin” that orbits just outside the inner radius of the habitable zone where liquid water can persist. Venus is now a sizzling global lava bed with some mountains jutting out of large igneous provinces (LIPs). At Phys.org, astronomer Paul Sutter opines that “Volcanoes may have killed Venus with a runaway greenhouse,” and that this has “Implications for Earth-bound volcanism.”
What turned Venus into hell? It could have simply been a steadily warming sun, but new research suggests that volcanoes may have played a role in creating a runaway greenhouse effect. And the same history of active Volcanism almost killed the Earth, too.
Sutter concludes that Earth escaped Venus’s fate “only by the skin of our teeth,” citing research about LIPs detected under Earth’s crust. If so, surviving a close call reinforces the argument that finely tuned geological conditions were required for life to flourish on our home planet.
Hoping against hope, Campbell and Whitten speculate in Geophysical Research Letters (“Crater Ejecta Across Maxwell Montes, Venus, and Possible Effects on Future Rock Type Measurements”) that future missions to Venus might find minerals on the surface that could have formed in water. That would have occurred billions of years ago, they realize. But then they douse hopes for such discoveries by concluding that impact dust probably covered up the evidence.
We show that much of Maxwell Montes, the tallest mountain range on Venus, is at least partly covered by impact-produced sediments that must be considered when analyzing future orbital observations.
The noble mountain range (pictured at the top of this article), at 36,000 feet above its surroundings (about twice the height of Everest), is named for James Clerk Maxwell, the eminent Victorian physicist (1831-1879). Maxwell is best known for elucidating the laws of electromagnetism that led to the revolution in wireless communication that the space age depends on. Maxwell, though, was no materialist. He was a strong Christian who disputed Darwin’s theory. One of the largest mountains in the solar system, Maxwell Montes is the only feature on Venus named after a scientist.
Astrobiologists have long searched for water on Mars, which orbits just outside the outer edge of the habitable zone. Planetary scientists believe Mars had large surface bodies of water in the past. Today only remnants of water ice remain in the soil and under the carbon dioxide ice caps at the poles.
Another plague on Mars that reduces its likelihood as a suitable habitat for life, though, is its leaky atmosphere. Unlike Earth, Mars has no strong global magnetic field — only a weak, patchy one — to protect it from incessant bombardment by solar charged particles. According to a paper in Geophysical Research Letters by Gu et al. (“Wind-Enhanced Hydrogen Escape on Mars”), the red planet may have lost its atmosphere faster than thought. Previous studies used the formulas for atmospheric escape modeled by Sir James Jeans. When the Mach number for wind speed is factored in, however, the escape of hydrogen is exacerbated.
A larger Mach number (due to a larger wind velocity, a lower temperature, a larger particle mass, or any combination of the three) implies a stronger degree of departure and consequently more enhanced escapeover the Jeans case.
Mars has other problems with habitability. “If life exists on Mars, it would face several challenges including the presence of perchlorates, which destabilize biomacromolecules by inducing chaotropic stress,” begins a preprint on bioRxiv by Heinz et al. These authors have strong faith that any putative life forms would have the ingenuity to resist the stress. Why? Because some Earth yeast cells have molecular mechanisms to do so!
These stress responses would also be relevant for life on Mars, which – given the environmental conditions — likely developed chaotropic defense strategies such as stabilized confirmations of biomacromolecules and the formation of cell clusters.
As in the Europa discussion above, that’s a far cry from the question of the origin of life in the first place.
Half of stars are binary systems. Astrobiologists at the University of Copenhagen reconsidered an assumption that planets around binary stars could not be habitable. They report on “Planets of binary stars as possible homes for alien life.” Using observations of dust and gas around binary star NGC 1333-IRAS2A, and building computer models from the data, they think that planets would form very differently around binary systems.
They’re only seeing a snapshot in time with the ALMA telescope, of course, but they believe “the team has complemented the observations with computer simulations reaching both backwards and forwards in time.” Unfortunately, the model adds challenges for life, let alone planet formation.
The two stars encircle each other, and at given intervals their joint gravity will affect the surrounding gas and dust disc in a way which causes huge amounts of material to fall towards the star.
“The falling material will trigger a significant heating. The heat will make the star much brighter than usual,” says Rajika L. Kuruwita, adding:
“These bursts will tear the gas and dust disc apart. While the disc will build up again, the bursts may still influence the structure of the later planetary system.”
They end by hoping that the James Webb Space Telescope that is currently beginning its first observations will shed light on the question of whether a planet, or a microbe, could survive such fireworks around binary stars.
Useful Work for ID
So bring it on! Astrobiology is doing useful work for intelligent design. Astrobiologists may still wish to believe that life follows the water, but good science follows the evidence where it leads. So far, the evidence from the observable cosmos is supporting Michael Denton’s thesis about nature’s remarkable fine-tuning for human existence. It’s a bit ironic that we wouldn’t know just how strong that evidence is without help from our friendly hostile witnesses in the Darwin space agency.