Lighter colors represent higher elevation in this image of Jezero Crater on Mars, the landing site for NASA's Mars 2020 mission. The oval indicates the landing ellipse, where the rover will be touching down on Mars. Credits: NASA/JPL-Caltech/MSSS/JHU-APL/ESA
Topics: Astrobiology, Mars, NASA, Space Exploration, Spaceflight
Scientists with NASA's Mars 2020 rover have discovered what may be one of the best places to look for signs of ancient life in Jezero Crater, where the rover will land on Feb. 18, 2021.
A paper published today in the journal Icarus identifies distinct deposits of minerals called carbonates along the inner rim of Jezero, the site of a lake more than 3.5 billion years ago. On Earth, carbonates help form structures that are hardy enough to survive in fossil form for billions of years, including seashells, coral and some stromatolites — rocks formed on this planet by ancient microbial life along ancient shorelines, where sunlight and water were plentiful.
The possibility of stromatolite-like structures existing on Mars is why the concentration of carbonates tracing Jezero's shoreline like a bathtub ring makes the area a prime scientific hunting ground.
Mars 2020 is NASA's next-generation mission with a focus on astrobiology, or the study of life throughout the universe. Equipped with a new suite of scientific instruments, it aims to build on the discoveries of NASA's Curiosity, which found that parts of Mars could have supported microbial life billions of years ago. Mars 2020 will search for actual signs of past microbial life, taking rock core samples that will be deposited in metal tubes on the Martian surface. Future missions could return these samples to Earth for deeper study.
Consider the possibility that an asteroid may have transformed the picture of life on Earth — but forget the dinosaurs and the massive crater, and rewind an extra 400 million years from that dramatic moment.
Back then, life was primarily an oceanic affair and backbones were the latest in arrival on the anatomy scene. But unlike the asteroid that killed the dinosaurs 66 million years ago, this earlier space rock never made it to Earth. Instead, a collision in the asteroid belt flooded the solar system with so much dust that, given some other changes at the time, allowed life on Earth to flourish, new research suggests.
"Most important events in the history of life are like that," said Rebecca Freeman, a paleontologist at the University of Kentucky who specializes in this period but wasn't involved in the new research. "You get a really unique set of circumstances that all come together, and you get a really dramatic event that maybe seems like it should be due to one particular dramatic thing. But in reality, it's a more complicated system at play," she told Space.com.
The dramatic event scientists want to explain is a spree of new species. That outburst of life, which paleontologists call the Great Ordovician Biodiversification Event, took place in the oceans, which were inhabited mostly by spineless creatures. "This is really a world that is dominated by invertebrate marine organisms," Freeman said. "Probably the top predator would have been a cephalopod," likely an ancestral relative of today's chambered nautilus, with its intricate spiral shell.
But when Birger Schmitz, a geologist at Lund University in Sweden, went hunting for rock dating back 466 million years, he wasn't hoping to find fossilized nautiluses; he was looking for fossilized meteorites. And over the past couple of decades, he and his colleagues have found dozens of these fossilized meteorites in a Swedish limestone quarry. Each carries a chemical time stamp indicating that it was heated about 470 million years ago, and scientists have thought for a while that there might have been a massive asteroid collision around that time.
The sea sloshing beneath the icy surface of Jupiter’s moon Europa just might be the best incubator for extraterrestrial life in our solar system. And yet it is concealed by the moon’s frozen outer shell—presenting a challenge for astrobiologists who would love nothing more than to peer inside. Luckily they can catch a partial glimpse by analyzing the flavor of the surface. And the results are salty.
A new study published this week in Science Advances suggests that sodium chloride—the stuff of table salt—exists on Europa’s surface. Because the exterior is essentially formed from frozen seawater, the finding suggests that Europa’s hidden sea is drenched in table salt—a crucial fact for constraining the possibilities for life on the alien world.
Not that scientists have tasted a slice of the distant moon. To analyze Europa’s composition, astronomers study the light emanating from its surface, splitting it into a rainbow-like spectrum to search for any telltale absorption or emission lines that reveal the world’s chemistry. There is just one problem: Ordinary table salt is white and thus gives off a featureless spectrum. But harsh radiation—which exists at Europa’s surface in abundance—just might add a dash of color. That much was realized in 2015 when two NASA planetary scientists Kevin Hand and Robert Carlson published a study suggesting the yellowish-brown gunk on Europa might be table salt baked by radiation. To reach that conclusion, Hand and Carlson re-created the conditions on Europa within vacuum chambers—or as Hand calls them, “stainless steel shiny objects that are humming and whizzing.” Next, they placed table salt into those chambers, lowered the pressures and temperatures to simulate Europa’s surface, and blasted the samples with an electron gun to simulate the intense radiation.
Topics: Astrobiology, Carl Sagan, Climate Change, Drake Equation, Existentialism, Fermi Paradox, Nuclear Power
“The universe is a pretty big place. If it's just us, seems like an awful waste of space.” Carl Sagan
My First Contact scenario doesn't involve Vulcans, warp drive or impossible scenarios: it involves radio transmissions, as communication is a big part of the Drake Equation. Specifically audio, video and digital data (Internet?) of extraterrestrial origin as we would confirm before announcing to the world. Assuming the aliens developed their technology in an oxygen-nitrogen environment, the language we could hear might amount to a lot of "clicking" noises, that mathematicians - specifically specialists in cryptography, and linguists - would dive into deciphering. Eventually after coming up with a Rosetta Stone of syntax, we could translate what would amount to news, drama and sitcoms. Of specific interest might be their political climate and sectarian strife (if any). More particularly, did they successfully translate through their "Great Filter"...
...or, if they did not.
I'm a big fan of Jordon Peele's incarnation of The Twilight Zone, particularly the sixth episode: "Six Degrees of Freedom." It is unfortunate that popular show title describes our current political climate.
I won't give away the intriguing ending, but Peele has mastered the macabre plot twist of Rod Serling's writing style, and (my opinion) his surreal monologue delivery. It's streaming, so you may have to pay less than you would for a single movie ticket per month to view it. I've enjoyed it andother shows so far, and I get no monetary gain for the endorsement.
"The Great Filter, in the context of the Fermi paradox, is whatever prevents dead matter from undergoing abiogenesis, in time, to expanding lasting life as measured by the Kardashev scale. The concept originates in Robin Hanson's argument that the failure to find any extraterrestrial civilizations in the observable universe implies the possibility something is wrong with one or more of the arguments from various scientific disciplines that the appearance of advanced intelligent life is probable; this observation is conceptualized in terms of a "Great Filter" which acts to reduce the great number of sites where intelligent life might arise to the tiny number of intelligent species with advanced civilizations actually observed (currently just one: human). This probability threshold, which could lie behind us (in our past) or in front of us (in our future), might work as a barrier to the evolution of intelligent life, or as a high probability of self-destruction. The main counter-intuitive conclusion of this observation is that the easier it was for life to evolve to our stage, the bleaker our future chances probably are.
The idea was first proposed in an online essay titled "The Great Filter - Are We Almost Past It?", written by economist Robin Hanson. The first version was written in August 1996 and the article was last updated on September 15, 1998. Since that time, Hanson's formulation has received recognition in several published sources discussing the Fermi paradox and its implications.
Using extinct civilizations such as Easter Island as models, a study conducted in 2018 posited that climate change induced by "energy intensive" civilizations may prevent sustainability within such civilizations, thus explaining the lack of evidence for intelligent extraterrestrial life." Source: Wikipedia/The Great Filter
The Great Filter is alluded to in science fiction with or without warp drive: Star Trek described global wars on Earth and the fictional Vulcan that involved their respective nuclear holocausts. For the Vulcans, recovery involved a relentless embrace of logic, or as I recall reading in a Trek novel, "reality-truth." For Earth, it essentially involved accepting help from the Vulcans after the human species was discovered warp capable through a singular genius with a funny name post self-induced Apocalypse, a Deus ex Machina plot device used since publicly performed Greek and Roman plays. We don't have warp drive, but we do have thermonuclear devices poised for Armageddon. We don't have Vulcans, but we once did have the Easter Islanders, just as once we had the Dodo.
I've often encapsulated The Great Filter in my own dictum: "intelligence is its own Entropy." I think when Carl Sagan was alive, the regressive forces we see now denying science, climate change; verifiable facts and reality were well engaged in his day of the original COSMOS. Slowly, shows like COSMOS lost their appeal to Game Shows cum Reality Shows, and as a country we reveled in our distractions, added as channels on cable and Internet multiplied like E. coli. and measles resurgenceas well as our grasp of what is real and verifiable. In fact, we seek distractions in gadgets and online machinations in the constant need to fill "horror vacui."
In the east, nothing meant something, particularly in clarity of thought: Mu Shin No Shin - "the mind without mind" or more colloquially, "no mind." As translated from the martial battlefield to artists both martial and objective; and Zen philosophers, it offers a certain clarity that can be attained when not focused on minutiae detail, but accepted reality "as-is" after diligent practice. A practice like karate forms that takes years of repetition, dedication and study. That is the key to mastering anything, from martial arts to science to civics.
The stars are silent. Intelligence may be rare. Vulcans if existing may not be benevolent, and in the myopic attention span of the erect species of which I am member - "wise men"...fleeting in longevity.