Noting the passing earlier this month of Frank Drake, author of the famous Drake Equation, planetary geoscientist David Rothery notes, we know a great deal more promising information about the search for life today than we did in 1961 when he first formulated the equation: “We are learning more about exoplanets every year, and are entering an era when measuring their atmospheric composition to reveal evidence of life is becoming increasingly feasible. Within the next decade or two, we can hope for a much more soundly based estimate of the fraction of Earth-like planets where life gets started.” – The Conversation, September 5, 2022. We also know about potentially habitable moons now (for example, Enceladus, whose image is featured above).
Around the galaxy:
As the uproar around the James Webb findings continues, MIT researchers warn that data about planets could be misinterpreted: “But a new MIT study suggests that the tools astronomers typically use to decode light-based signals may not be good enough to accurately interpret the new telescope’s data. Specifically, opacity models — the tools that model how light interacts with matter as a function of the matter’s properties — may need significant retuning in order to match the precision of JWST data, the researchers say.” For example, “‘There is a scientifically significant difference between a compound like water being present at 5 percent versus 25 percent, which current models cannot differentiate,’ says study co-leader Julien de Wit, assistant professor in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS).” – MIT News Office, September 15, 2022. Okay but at least we now have data over which to have a dispute.
“Alien worlds could be discovered by hunting for debris orbiting them”: “When two celestial bodies are gravitationally bound, such as a star and a planet, there are five points in space where their gravity and orbital motion essentially cancel each other out. At these Lagrange points, which are named L1 through L5, material stays put, essentially frozen in space. – Stefanie Waldek, Space.com, September 18, 2022. An open-access paper discusses one such planet. Here’s more on Lagrange points — interplanetary parking lots.
And in our solar system:
“Saturn Moon Enceladus Has ‘Almost All’ Ingredients for Life in Its Icy Ocean”:
“While a frozen shell hides the distant world, it hides a liquid water ocean below that appears to have all the basic requirements for life to survive … Now, a new study uses computer modeling to suggest the ocean on Enceladus should also be filled with dissolved phosphorus, which is key to supporting life as we know it” … “What we have learned is that the plume contains almost all the basic requirements of life as we know it,” Glein said. “While the bioessential element phosphorus has yet to be identified directly, our team discovered evidence for its availability in the ocean beneath the moon’s icy crust,” Southwest Research Institute’s Christopher Glein, who has been studying Enceladus for years, said in a statement.” – Eric Mack, C.NET, Sept. 20, 2022. The paper is open access.
Some astrobiologists consider Enceladus, along with Europa, as better than Mars for life. For one thing, it has water.
China’s Mars mission offers evidence for an ancient ocean: “Now, CGTN reports that CNSA has announced that the orbiter and rover have sent back 1,480 gigabytes of raw data — some of which supports the hypothesis that an ancient ocean once existed in the Utopia Planitia, the vast Martian plain that Zhurong is exploring… Scientists analyzing the data have discovered the existence of hydrated minerals in the “duricrust,” a hard mineral layer atop soil that typically forms due to the evaporation of groundwater. The scientists claim that this finding proves there has been “substantial liquid water activity” in the region at some point over the last billion years. They’ve also determined “that the Martian soil has high bearing strength and low friction parameters,” which would indicate erosion due to wind, water or both. – Stefanie Walden, Space.com, September 20, 2022.
Also, “Mars Might Have Been Covered in Lakes in the Ancient Past: “The ultimate purpose here is to determine whether rivers, streams, and standing bodies of water existed long enough for life to emerge. So far, missions like Curiosity and Perseverance have gathered volumes of evidence that show how hundreds of large lakebeds once dotted the Martian landscape. But according to a new study by an international team of researchers, our current estimates of Mars’ surface water may be a dramatic understatement. Based on a meta-analysis of years’ worth of satellite data, the team argues that ancient lakes may have once been a very common feature on Mars.” – Matt Williams, Universe Today (September 22, 2022).
Meanwhile, the James Webb has spotted “catastrophic ancient damage” on Mars:
“Using the scope’s Near-Infrared Camera (NIRCam), astronomers got a new look at the Hellas Basin, believed to have formed some four billion years ago when an unknown object of gargantuan proportions smashed into Mars’ surface when the poor planet was still young. At 4,400 miles across, it shows up in NIRCam’s images as a massive dark-orange spot in the infrared spectrum, amidst the bright yellow of Mars’ subsolar point, the point where the sun is directly overhead.” — Frank Landymore, Futurism, September 22, 2022.
Incidentally, here’s the sound of a meteoroid striking Mars, courtesy NASA. It’s kind of a “thok” sound.
And lastly, here’s another one of University of Western Australia cosmologist Luke Barnes’s examples of the way our universe is fine-tuned for life: The fact that our universe has only three space dimensions. Now, some might say, of course it only has three space dimensions. But actually, more space dimensions are possible. What we also know, however, is this:
It has been known for some time that Newtonian gravity only predicts stable planetary orbits in three space dimensions (Bertrand’s theorem). With four space dimensions, for example, slightly non-circular orbits are spiralled, not elliptical — they would send the planet into the star or off into empty space. The same applies to atomic orbits described by the Schrodinger equation — there is no stable ground state.Luke Barnes, “The Fine-Tuning of the Universe for Life” at ArXiv (October 18, 2021)
4-D world fun:
You may also wish to read: News from the search for extraterrestrial life 5 NASA staff are said to be quite excited about organic materials around the Jezero Crater; astronomers are learning more about “eyeball planets” Sasha Quant, who shared the 1995 Nobel Prize for finding the first exoplanet, thinks, with so many watery planets, we could find exoplanet life in 25 years. (September 17, 2022) Links are available there to all earlier news roundups.