As the telescopes and other instruments rain data on researchers, each week brings news of interest:
From our galaxy:
Last week, planets orbiting M-type (common red dwarf) stars came up. Astronomers are classifying these planets in greater detail: “’We have discovered that small planets orbiting this type of star can be classified into three distinct families: rocky planets very similar to Earth, planets with half their mass consisting of water that we call water worlds, and mini-Neptunes with extended atmospheres of hydrogen and/or helium’, describes Pallé.” – Instituto de Astrofísica de Canarias (IAC) (September 8, 2022)
One feature of these worlds may be a surprise: “Given that they are tidally locked to their suns, these planets may also have liquid oceans on their sun-facing side but frozen surfaces everywhere else – colloquially known as “eyeball planets.” While astronomers have speculated about the existence of this class of exoplanet, these findings constitute the first confirmation for this new type of exoplanet. They also bolster the growing case for water worlds that form beyond the so-called “snow line” in star systems (the boundary beyond which volatile elements freeze solid), then migrate closer to their star.” – Matt Williams, Universe Today, (September 14, 2022)
Sasha Quanz, an astrophysicist at Switzerland’s federal technology institute ETH Zurich, thinks that, given all the new equipment, it’s “not ‘unrealistic’” that we might detect evidence of life on other planets in the next quarter century. He shared the Nobel Prize for 1995 for discovering the first exoplanet. His reasoning: “Of those thousands of exoplanets, dozens are believed to be at least potentially habitable, with the conditions on their surface ripe for liquid water. And as he said, that number is growing all the time.” – Noor Al-Sibai, Futurism, (September 13, 2022)
In our solar system:
Some are looking within our solar system for evidence of intelligent extraterrestrials. This type of evidence is called technosignatures — artifacts only an intelligent life form would create. An article at Universe Today looks at the methods and rationale. There is a new focus on physical objects via the new Vera C. Rubin Observatory (2023): “Focusing on physical artifacts is a new strategy in SETI, but Loeb and Laukien are optimistic. Artifacts, they point out, are necessarily less fleeting than radio signals. While an object might be technically more difficult to detect than a signal, an object would not have to somehow repeat itself if missed the first time. Also unlike light, most physical objects in our galaxy are gravitationally bound to it. This makes detection less time-critical for a physical object.” – Seth Lockman, Universe Today (September 13, 2022)
Next door (Mars):
We’re told that NASA’s Perseverance Rover “has collected samples from one of the best places to search for ancient life on Mars.” That’s the 3.5 billion-year-old Jezero Crater located at what seems to be a river meeting a lake. “Now in its second science campaign, the rover is studying the delta, where it has found organic materials. While organics have been found on Mars before by both Perseverance and the Curiosity rover, this latest detection was made in an area where, in the distant past, sediment and salts were deposited into a lake under conditions in which life could potentially have existed.” – Nancy Atkinson, Universe Today (September 15, 2022) Details from NASA here.
At Futurism, Frank Landymore notes that NASA personnel seem quite excited by their finds: “What [Perseverance] found was organic molecules related to sulfate, likely meaning that as the lake was drying up, that particular area became highly concentrated in both sulfate and organic.” The samples may not provide evidence of life but they’re the ones to get hold of. (September 16, 2022)
Also, we learn at Phys.org that the number of ancient Martian lakes might have been dramatically underestimated by scientists. “We know of approximately 500 ancient lakes deposited on Mars, but nearly all the lakes we know about are larger than 100 km2,” explains [Joseph] Michalski. “But on Earth, 70% of the lakes are smaller than this size, occurring in cold environments where glaciers have retreated. These small-sized lakes are difficult to identify on Mars by satellite remote sensing, but many small lakes probably did exist. It is likely that at least 70% of Martian lakes have yet to be discovered.” Scientists monitor these small lakes on Earth in order to understand climate change. The missing small lakes on Mars might also contain critical information about past climates.” – University of Hong Kong (September 16, 2022. The paper requires a fee or subscription.)
As we explore…
As noted earlier, one reason to believe we can find life on other planets is that our universe is fine-tuned for life. University of Western Australia cosmologist Luke Barnes offers a number of interesting examples. Here’s another one:
As an example of fine-tuning for life, the cosmological constant problem is a near-perfect storm …
The cosmological constant has a very obvious and definitive effect on the necessary conditions for life. A positive cosmological constant causes the expansion of the universe to accelerate, freezing structure formation. Make the cosmological constant a few orders of magnitude larger and structure formation freezes before anything has formed. The universe will be a thin, uniform hydrogen and helium soup, a diffuse gas where the occasional particle collision is all that ever happens. A very simple way to make a universe lifeless is to make it devoid of any structure whatsoever. Alternatively, a negative cosmological constant causes the universe to recollapse.Luke Barnes, “The Fine-Tuning of the Universe for Life” at ArXiv (October 18, 2021)
But our universe has just the right one.
Here are news notes from the last month or so:
News from the search for extraterrestrial life 4. Just as much promising data about habitable planets is streaming in from the telescopes, pioneer ET astronomer Frank Drake has died. A new class of planets — half rock and half water — has been found, and a super-Earth that is clearly in the habitable zone.
News from the search for extraterrestrial life 3: The Webb gets a good closer look at an exoplanet. In other news, we’re learning more about Europa’s oceans, an ancient Martian lake, a star with “squarish” waves — and asteroids that are too close to home. (September 3, 2022)
News from the search for extraterrestrial life 2: A new ocean planet, a planet with carbon dioxide, and new discoveries about life chances on Mars. Progress? We now need the Artemis Accords to divvy up nations’ rights re Moon exploration — and the far side might host a telescope better than the Webb. One reason for hope for finding life elsewhere in the universe is that the universe appears to be fine-tuned for life. What the universe won’t do is tell us where the life is. (August 27, 2022)
News from the search for extraterrestrial life I: Super-Earths that might have life, choosing life forms to take to Mars, and self-replicating robots… NASA is looking at developing a swarm of tiny robots to look for extraterrestrial life on oceanic worlds like Europa or Enceladus. (August 20, 2022)