BLOGS

Topics: Applied Physics, Astrobiology, Astrophysics, Civilization, Climate Change, Existentialism, Exoplanets, SETI, Thermodynamics

Well, this firmly puts a kink in the "Fermi Paradox."

The Industrial Revolution started in Britain around 1760 - 1840, and there was a colloquial saying that "the sun did not set on the British Empire." The former colony, America, cranked up its industrial revolution around 1790. Mary Shelley birthed the science fiction genre in the dystopian Frankenstein in 1818, around the time of climate-induced change of European weather, and a noticeable drop in temperature. It was also a warning of the overconfidence of science, the morality that should be considered when designing new technologies, its impact on the environment, and humans that sadly, don't think themselves a part of the environment. The divide between sci-fi is dystopian and Pollyannish: Star Trek mythology made that delicate balance between their fictional Eugenics Wars, World War III, the "Atomic Horror," and a 21st Century dark age, the discovery of superluminal space travel, and First Contact with benevolent, pointy-eared aliens, leading to Utopia post xenophobia. We somehow abandoned countries and currency, and thus, previous hierarchal power and inequality modalities. Roddenberry's dream was a secular version of Asgard, Heaven, Olympus, and Svarga: a notion of continuance for a species aware of its finite existence, buttressed by science and space lasers.

If aliens had a similar industrial revolution, they perhaps created currencies that allowed for trade and commerce, hierarchies to decide who would hoard resources, and which part of their societies were functionally peasantry. They would separate by tribes, complexions, and perhaps stripes if they're aquatic, and fight territorial wars over resources. Those wars would throw a lot of carbon dioxide in their oxygenated atmospheres. Selfishness, hoarding disorder, and avarice would convince the aliens that the weather patterns were "a hoax," they would pay the equivalent of lawyers to obfuscate the reality of their situations before it was too late on any of their planets to reverse the effects on their worlds. If they were colonizing the stars, it wouldn't be for the altruistic notion of expanding their knowledge by "seeking out life, and new civilizations": they would have exceeded the thermal budgets of their previous planets. Changing their galactic zip codes would only change the locations of their eventual outcomes.

Thermodynamics wins, and Lord Kelvin may have answered Enrico Fermi's question. Far be it for me to adjudicate whether or not anyone has had a "close encounter of the third kind," but I don't see starships coming out of this scenario. Cogito ergo sum homo stultus.

It may take less than 1,000 years for an advanced alien civilization to destroy its own planet with climate change, even if it relies solely on renewable energy, a new model suggests.

When astrophysicists simulated the rise and fall of alien civilizations, they found that, if a civilization were to experience exponential technological growth and energy consumption, it would have less than 1,000 years before the alien planet got too hot to be habitable. This would be true even if the civilization used renewable energy sources, due to inevitable leakage in the form of heat, as predicted by the laws of thermodynamics. The new research was posted to the preprint database arXiv and is in the process of being peer-reviewed.

While the astrophysicists wanted to understand the implications for life beyond our planet, their study was initially inspired by human energy use, which has grown exponentially since the 1800s. In 2023, humans used about 180,000 terawatt hours (TWh), which is roughly the same amount of energy that hits Earth from the sun at any given moment. Much of this energy is produced by gas and coal, which is heating up the planet at an unsustainable rate. But even if all that energy were created by renewable sources like wind and solar power, humanity would keep growing, and thus keep needing more energy."

This brought up the question, 'Is this something that is sustainable over a long period of time?'" Manasvi Lingam, an astrophysicist at Florida Tech and a co-author of the study, told Live Science in an interview.

Lingam and his co-author Amedeo Balbi, an associate professor of astronomy and astrophysics at Tor Vergata University of Rome, were interested in applying the second law of thermodynamics to this problem. This law says that there is no perfect energy system, where all energy created is efficiently used; some energy must always escape the system. This escaped energy will cause a planet to heat up over time.

"You can think of it like a leaky bathtub," Lingam said. If a bathtub that is holding only a little water has a leak, only a small amount can get out, he explained. But as the bathtub is filled more and more — as energy levels increase exponentially to meet demand — a small leak can suddenly turn into a flooded house.

Alien civilizations are probably killing themselves from climate change, bleak study suggests, Sierra Bouchér, Live Science

Topics: Astrobiology, Biology, Instrumentation, James Web Space Telescope, Research, SETI

"The Secret Life of the Universe" by Dr. Nathalie Cabrol, the SETI Institute's chief scientist and Director of the Carl Sagan Center at the SETI Institute, is coming out this week, both in the US (August 13, 2024) and in the UK (August 15, 2024). Scriber/Simon & Schuster publishes both editions. Cabrol articulates an overview of where we stand today in our search for life in the universe, what's coming, and how looking out for life beyond Earth teaches us about our place on our planet.

Here is an excerpt to inspire you:

On July 11, 2022, the James Webb Space Telescope (JWST) returned its first images, penetrating the wall of time to show us the universe just a few hundred million years after its formation. In a marvelous cosmic irony, this immersion into the depths of our origins propels us into the future, where a revolution looms large in astronomy, in cosmology, and in astrobiology—the search for life in the universe. JWST comes after a few decades of space and planetary exploration during which we have discovered countless habitable environments in our solar system—for (simple) life as we know it, but also thousands of exoplanets in our galaxy, some of them located in the habitable zone of their parent stars.

We are living in a golden age in astrobiology, the beginning of a fantastic odyssey in which much remains to be written, but where our first steps bring the promise of prodigious discoveries. And these first steps have already transformed our species in one generation in a way that we cannot foresee just yet.

Copernicus taught us long ago that the Earth was neither at the center of the universe nor the center of the solar system, for that matter. We also learned from the work of Harlow Shapley and Henrietta Swan Leavitt that the solar system does not even occupy any particularly prominent place in our galaxy. It is simply tucked away at the inner edge of Orion’s spur in the Milky Way, 27,000 light-years from its center, in a galactic suburb of sorts. Our sun is an average-sized star located in a galaxy propelled at 2.1 million kilometers per hour in a visible universe that counts maybe 125 billion such cosmic islands, give or take a few billion. In this immensity, the Kepler mission taught us that planetary systems are the rule, not the exception.

This is how, in a mere quarter of a century, we found ourselves exploring a universe populated by as many planets as stars. Yet, looking up and far into what seems to be an infinite ocean of possibilities, the only echoes we have received so far from our explorations have been barren planetary landscapes and thundering silence. Could it be that we are the only guests at the universal table? Maybe. As a scientist, I cannot wholly discount this hypothesis, but it seems very unlikely and “an awful waste of space,” and for more than one reason.

The Secret Life of the Universe, ?ETI Institute

The completed VIPER rover awaits one of two fates: be sent to the Moon by an organization other than NASA or be cannibalized for its parts and instruments. Credit: NASA

Topics: Astrobiology, Astronautics, Astrophysics, Chemistry, COVID-19, NASA, Space Exploration, Spectrographic Analysis

"Boldly going" has budget constraints, but all is not lost. "Plan B" is at the link below.

The VIPER rover was meant to be a key scouting mission ahead of NASA’s Artemis program, collecting crucial information about water-ice reserves at the lunar south pole.

To the shock of the lunar science community, on July 17, NASA cancelled the much-anticipated Volatiles Investigating Polar Exploration Rover (VIPER) mission, which was expected to prospect for water ice on the Moon — a critical resource for future explorers.

VIPER was one of the highest profile missions in NASA’s ongoing Commercial Lunar Payload Services (CLPS) program, which that is sending robotic missions to the Moon in support of future Artemis crews. Artemis targets landing near the lunar south pole, where the shallow angle of the Sun means many craters lie in permanent shadow. Scientists know that these craters contain water ice, which could be used as drinking water for astronauts and as a resource for rocket fuel and energy production. But we don’t know how much ice is there, nor how easy it will be to extract. VIPER’s mission was to answer those questions — and its cancellation deprives the Artemis program of critical data.

Equally shocking to the science community is that $450 million has already been spent designing and building VIPER and its suite of instruments. The completed VIPER only needed to pass its environmental tests to ensure it could survive in the Moon’s incredibly harsh, perpetually shadowed polar regions. The rover and the Astrobiotics Griffin lunar lander that was to deposit VIPER near the south pole were scheduled to launch in September 2025 aboard a SpaceX Falcon Heavy rocket.

NASA has said it is open to handing VIPER over to another organization to fly it to the Moon — if it comes at no additional cost to NASA. If no takers emerge, current plans call for the dismantling of VIPER and cannibalizing its instruments for possible use in future missions.

NASA’s explanation for VIPER’s cancellation is that COVID-induced supply chain issues with both the rover and its Griffin lander escalated mission costs and have delayed its anticipated launch by two years. By cancelling the project, after already spending nearly half a billion dollars, NASA says it will save $84 million. At the same time, NASA will pay Astrobiotics $323 million to complete the Griffin lander and fly it to the Moon without VIPER. At this time, plans call for landing a “mass simulator,” or a dead weight, that will return no science data about the Moon.

NASA cancels fully built Moon rover, stunning scientists, Robert Reeves, Astronomy.com.

Filled with briny lakes, the Quisquiro salt flat in South America's Altiplano region represents the kind of landscape that scientists think may have existed in Gale Crater on Mars, which NASA's Curiosity Rover is exploring. Credit: Maksym Bocharov

Topics: Astrobiology, Astrophysics, Atmospheric Science, Mars, NASA, Planetary Science

The most surprising revelation from NASA's Curiosity Mars Rover—that methane is seeping from the surface of Gale Crater—has scientists scratching their heads.

Living creatures produce most of the methane on Earth. But scientists haven't found convincing signs of current or ancient life on Mars, and thus didn't expect to find methane there. Yet, the portable chemistry lab aboard Curiosity, known as SAM, or Sample Analysis at Mars, has continually sniffed out traces of the gas near the surface of Gale Crater, the only place on the surface of Mars where methane has been detected thus far. Its likely source, scientists assume, are geological mechanisms that involve water and rocks deep underground.

If that were the whole story, things would be easy. However, SAM has found that methane behaves in unexpected ways in Gale Crater. It appears at night and disappears during the day. It fluctuates seasonally and sometimes spikes to levels 40 times higher than usual. Surprisingly, the methane also isn't accumulating in the atmosphere: ESA's (the European Space Agency) ExoMars Trace Gas Orbiter, sent to Mars specifically to study the gas in the atmosphere, has detected no methane.

Why is methane seeping on Mars? NASA scientists have new ideas, Lonnie Shekhtman, NASA, Phys.org.

Two researchers have revised the Drake equation, a mathematical formula for the probability of finding life or advanced civilizations in the universe.

University of Rochester. Are We Alone in the Universe? Revisiting the Drake Equation, NASA

Topics: Astrobiology, Astrophysics, Artificial Intelligence, Civilization, SETI

See: Britannica.com/The-Fermi-Paradox/Where-Are-All-The-Aliens

Abstract
This study examines the hypothesis that the rapid development of Artificial Intelligence (AI), culminating in the emergence of Artificial Superintelligence (ASI), could act as a "Great Filter" that is responsible for the scarcity of advanced technological civilizations in the universe. It is proposed that such a filter emerges before these civilizations can develop a stable, multiplanetary existence, suggesting the typical longevity (L) of a technical civilization is less than 200 years. Such estimates for L, when applied to optimistic versions of the Drake equation, are consistent with the null results obtained by recent SETI surveys, and other efforts to detect various techno-signatures across the electromagnetic spectrum. Through the lens of SETI, we reflect on humanity's current technological trajectory – the modest projections for L suggested here, underscore the critical need to quickly establish regulatory frameworks for AI development on Earth and the advancement of a multiplanetary society to mitigate against such existential threats. The persistence of intelligent and conscious life in the universe could hinge on the timely and effective implementation of such international regulatory measures and technological endeavors.

Is artificial intelligence the great filter that makes advanced technical civilizations rare in the universe? Michael A. Garrett, Acta Astronautica, Volume 219, June 2024, Pages 731-735

The Bulletin of the Atomic Scientists shifted the Doomsday Clock to 90 seconds to midnight at a news conference in January 2023. From left, Siegfried Hecker, Daniel Holz, Sharon Squassoni, Mary Robinson and Elbegdorj Tsakhia (Photo credit: Patrick Semansky).

Topics: Astrobiology, Civilization, Existentialism, Science Fiction, SETI, Space Exploration

A few weeks ago, I posted “Wine of Consciousness” on Friday without commentary. There were many directions I could have taken. I did want to see how readers would react. As I postulated, the viewership was limited. There were many directions that I COULD have taken the post. Still, I decided every iteration was getting a little too “pop science” for my taste, and that can quickly cross over into pseudo without critical thinking.

Avi Loeb is popularly known for his hypothesis that Oumuamua (“scout” in Polynesian) wasn’t a meteor or comet but a possible extraterrestrial probe sent by an intelligence with a similar understanding of physics and the limitations of intergalactic travel: without something like 99% the speed of light (warp velocity is still the providence of science fiction), such journeys are not possible within the normal span of lifetimes. Dr. Loeb is a theoretical physicist in the Department of Astronomy at Harvard.

I’m from the generation that grew up hearing about “UFOs” (unidentified flying objects), “flying saucers,” and “little green men.” Green succumbed to gray, grey, or “the grays/greys” (E.T.: The Extra-Terrestrial), and now we’re discussing UAPs (unidentified aerial phenomena).

Another theoretical physicist has tackled the challenge by publishing another book: “UFOs: Unidentified Aerial Phenomena: Observations, Explanations, and Speculations (Paperback)” in what appears to be a lucrative cottage industry.

When someone asks me if I believe there is life elsewhere in the universe, I will say yes. Amoeba is life, bacteria is life, viruses: the jury is still out on whether or not they are alive in the biological sense.

I have often wondered if intelligence is its own Entropy: that the very systems any sentient species would create for itself in governing resources, governments, commerce, and space exploration would be its undoing, which might answer The Fermi Paradox.

The hope of extraterrestrials existing and interacting with Earth mortals might be a cultural wish: a hope that despite our alarming tendency to screw things up, we either might survive our boundless hubris, or SOMEONE will save us from our stupidity, Deus ex machina, or benevolent Vulcans.

Homo Sapiens is Latin for “wise men.”

Homo Stultus (“stupid men”) seems more apropos.

Is a More Advanced Civilization an Oxymoron? Avi Loeb, Medium

The sample return capsule from NASA's OSIRIS-REx mission is seen shortly after touching down in the desert at the Department of Defense's Utah Test and Training Range. Keegan Barber/NASA

Topics: Asteroids, Astrobiology, Astrophysics, NASA, Space Exploration

Scientists are exulting over the safe arrival of a canister containing about a cup's worth of asteroid rocks, collected 200 million miles away, that landed in a Utah desert after a 7-year NASA mission sent to retrieve them.

The black pebbles and dirt are older than Earth and are undisturbed remnants of the solar system's early days of planet formation. As part of an asteroid named Bennu, these rocks traveled unsullied through space for eons.

While bits of asteroids regularly fall to our planet as meteorites, scientists want to study pristine asteroid material, stuff that's uncontaminated by our planet, to understand the early chemistry that might have contributed to the emergence of life.

NASA asteroid sample lands safely in Utah before being whisked away by helicopter, Nell Greenfieldboyce, NPR

The galaxy observed by Webb shows an Einstein ring caused by a phenomenon known as gravitational lensing.  Credit: S. Doyle / J. Spilker

Topics: Astrobiology, Biology, James Webb Space Telescope, Space Exploration

Researchers have detected complex organic molecules in a galaxy more than 12 billion light-years away from Earth—the most distant galaxy in which these molecules are now known to exist. Thanks to the capabilities of the recently launched James Webb Space Telescope and careful analyses from the research team, a new study lends critical insight into the complex chemical interactions that occurred in the first galaxies in the early universe.

University of Illinois Urbana-Champaign astronomy and physics professor Joaquin Vieira and graduate student Kedar Phadke collaborated with researchers at Texas A&M University and an international team of scientists to differentiate between infrared signals generated by some of the more massive and larger dust grains in the galaxy and those of the newly observed hydrocarbon molecules.

The study findings are published in the journal Nature.

"This project started when I was in graduate school studying hard-to-detect, very distant galaxies obscured by dust," Vieira said. "Dust grains absorb and re-emit about half of the stellar radiation produced in the universe, making infrared light from distant objects extremely faint or undetectable through ground-based telescopes."

In the new study, the JWST received a boost from what the researchers call "nature's magnifying glass"—a phenomenon called gravitational lensing. "This magnification happens when two galaxies are almost perfectly aligned from the Earth's point of view, and light from the background galaxy is warped and magnified by the foreground galaxy into a ring-like shape, known as an Einstein ring," Vieira said.

Webb Space Telescope detects the universe's most distant complex organic molecules, Lois Yoksoulian, University of Illinois at Urbana-Champaign.

Life on other planets might not look like any beings we’re used to on Earth. It may even be unrecognizable at first to scientists searching for it. Credit: William Hand

Topics: Astrobiology, Astronomy, Astrophysics, Planetary Science, SETI, Space Exploration

Sarah Stewart Johnson was a college sophomore when she first stood atop Hawaii’s Mauna Kea volcano. Its dried lava surface differed from the eroded, tree-draped mountains of her home state of Kentucky. Johnson wandered away from the other young researchers she was with and toward a distant ridge of the 13,800-foot summit. Looking down, she turned over a rock with the toe of her boot. To her surprise, a tiny fern lived underneath it, sprouting from ash and cinder cones. “It felt like it stood for all of us, huddled under that rock, existing against the odds,” Johnson says.

Her true epiphany, though, wasn’t about the hardiness of life on Earth or the hardships of being human: It was about aliens. Even if a landscape seemed strange and harsh from a human perspective, other kinds of life might find it quite comfortable. The thought opened up the cosmic real estate and the variety of life she imagined might be beyond Earth’s atmosphere. “It was on that trip that the idea of looking for life in the universe began to make sense to me,” Johnson says.

Later, Johnson became a professional at looking. As an astronomy postdoc at Harvard University in the late 2000s and early 2010s, she investigated how astronomers might use genetic sequencing—detecting and identifying DNA and RNA—to find evidence of aliens. Johnson found the work exciting (the future alien genome project!), but it also made her wonder: What if extraterrestrial life didn’t have DNA, RNA, or other nucleic acids? What if their cells got instructions in some other biochemical way?

As an outlet for heretical thoughts like this, Johnson started writing in style too lyrical and philosophical for scientific journals. Her typed musings would later turn into the 2020 popular science book The Sirens of Mars. Inside its pages, she probed the idea that other planets were truly other. So their inhabitants might be very different, at a fundamental and chemical level, from anything in this world. “Even places that seem familiar—like Mars, a place that we think we know intimately—can completely throw us for a loop,” she says. “What if that’s the life case?”

The Search for Extraterrestrial Life as We Don’t Know It, Sarah Scoles, Scientific American

An Orbitrap cell. Credit: Ricardo Arevalo

Topics: Astrobiology, Astronautics, Biology, Laser, NASA, Planetary Science, Space Exploration

As space missions delve deeper into the outer solar system, the need for more compact, resource-conserving, and accurate analytical tools have become increasingly critical—especially as the hunt for extraterrestrial life and habitable planets or moons continues.

A University of Maryland–led team developed a new instrument specifically tailored to the needs of NASA space missions. Their mini laser-sourced analyzer is significantly smaller and more resource efficient than its predecessors—all without compromising the quality of its ability to analyze planetary material samples and potential biological activity onsite. The team's paper on this new device was published in the journal Nature Astronomy on January 16, 2023.

Weighing only about 17 pounds, the instrument is a physically scaled-down combination of two important tools for detecting signs of life and identifying compositions of materials: a pulsed ultraviolet laser that removes small amounts of material from a planetary sample and an Orbitrap analyzer that delivers high-resolution data about the chemistry of the examined materials.

"The Orbitrap was originally built for commercial use," explained Ricardo Arevalo, lead author of the paper and an associate professor of geology at UMD. "You can find them in the labs of pharmaceutical, medical and proteomic industries. The one in my own lab is just under 400 pounds, so they're quite large, and it took us eight years to make a prototype that could be used efficiently in space—significantly smaller and less resource-intensive but still capable of cutting-edge science."

The team's new gadget shrinks down the original Orbitrap while pairing it with laser desorption mass spectrometry (LDMS)—techniques that have yet to be applied in an extraterrestrial planetary environment. The new device boasts the same benefits as its larger predecessors but is streamlined for space exploration and onsite planetary material analysis, according to Arevalo.

Small laser device can help detect signs of life on other planets, University of Maryland, Phys.org.

(Credit: ktsdesign/Shutterstock)

Topics: Astrobiology, Astrophysics, Civilization, Existentialism, Philosophy, Special Relativity

The Cold War was a genesis of angst about the future due to the detonation of the atomic bomb by the Soviet Union in Kazakstan in 1949. After WWII (WWI was originally called, "the war to END all wars," until the sequel), the existential nervousness is understandable. Extraterrestrials, or musings about them, let humans off the hook if the Earth is rendered dystopic, and uninhabitable (with respect to "War of the Worlds" Martians), and some more advanced species to come to save us from our screw-ups (Star Trek Vulcans). Trek aliens that aren't that hospitable are the Gorn and Klingons. Neither of which I'd prefer to see on first contact. However, the vast distance between stars, relativistic speeds, and the drag of mass on even reaching a fraction of the speed of light make that possibility remote.

*****

In September 1961, Barney and Betty Hill were driving late at night in the mountains of New Hampshire when they saw a flying object whizzing in the sky. Barney thought it was a plane until he saw it swiftly switch directions.

According to The Interrupted Journey, the couple nervously continued driving until a spacecraft confronted them. They remembered seeing “humanoid-like” creatures and hearing pinging sounds reverberating off their car trunk. And then, they found themselves 35 miles further along on the highway with almost no memory of what had just transpired. They believed they had been abducted.

Scholars mark 1947 as the start of the UFO fascination. A pilot flying in the Cascade Mountains in Washington state reported seeing disc-shaped objects. In the next decade, aliens were primarily seen as benevolent, intelligent beings who came to Earth to offer advice or warnings.

In 1961, the Hills reported their abduction, and stories about aliens became more sinister. Social scientists, like famed psychologist Carl Jung, analyzed the UFO obsession and found it fit neatly with humans’ long fascination with heavenly ascents. Whereas past societies looked for angels, saints, or Gods to descend from the heavens, modern Americans were looking for “technological angels.”

Starting in the 1960s, aliens were both benign angels and menacing demons, which prompted some religious scholars to see UFO fixation as a modern religious movement.

Our Fascination With Aliens and When it All Started, Emilie Le Beau Lucchesi, Discover Magazine

Topics: Astrobiology, Astronomy, Astrophysics, Carl Sagan, James Webb Space Telescope, SETI

The relief was as deep as the stakes were high. At 7:20 A.M. (ET), the rocket carrying the largest, most ambitious space telescope in history cleared the launchpad in French Guiana, and the members of mission control at the Space Telescope Science Institute in Baltimore roared their elation.

The suspense was not quite over. Half an hour postlaunch, the telescope still needed to decouple from its host rocket, after which it had to deploy solar panels to partly power its journey. Only after that first deployment proved successful, said a NASA spokesperson in a statement to Scientific American, would “we know we have a mission.”

Astronomers have more riding on the rocket than the James Webb Space Telescope (JWST). Also at risk is the viability of NASA’s vast space-science portfolio, if not the future of astronomy itself. As the successor to the Hubble Space Telescope (HST), JWST is one of those once-in-a-generation scientific projects that can strain the patience of government benefactors, as well as the responsible agency’s credibility, but also define a field for decades to come—and possibly redefine it forever.

The telescope that would become JWST was already under discussion even before HST launched in April 1990. By orbiting Earth, HST would have a line of sight free of the optical distortions endemic to our planet’s atmosphere. It would therefore be able to see farther across the universe (and, given that the speed of light is finite, farther back in time) than any terrestrial telescope.

The James Webb Space Telescope Has Launched: Now Comes the Hard Part, Richard Panek, Scientific American

The depiction of tentacled extraterrestrials (above) in the recent science-fiction film, "Arrival, "indicates divergence from aliens reported by supposed eyewitness accounts. Paramount. Source: Wrinkles, tentacles and oval eyes: How depictions of aliens have evolved, CNN Style

Topics: Astrobiology, Philosophy, SETI, Space Exploration

In my freshman seminar at Harvard last semester, I mentioned that the nearest star to the sun, Proxima Centauri, emits mostly infrared radiation and has a planet, Proxima b, in the habitable zone around it. As a challenge to the students, I asked: “Suppose there are creatures crawling on the surface of Proxima b? What would their infrared-sensitive eyes look like?” The brightest student in class responded within seconds with an image of the mantis shrimp, which possesses infrared vision. The shrimp’s eyes look like two ping-pong balls connected with cords to its head. “It looks like an alien,” she whispered.

When trying to imagine something we’ve never seen, we often default to something we have seen. For that reason, in our search for extraterrestrial life, we are usually looking for life as we know it. But is there a path for expanding our imagination to life as we don’t know it?

In physics, an analogous path was already established a century ago and turned out to be successful in many contexts. It involves conducting laboratory experiments that reveal the underlying laws of physics, which in turn apply to the entire universe. For example, around the same time when the neutron was discovered in the laboratory of James Chadwick in 1932, Lev Landau suggested that there might be stars made of neutrons. Astronomers realized subsequently that there are, in fact, some 100 million neutron stars in our Milky Way galaxy alone—and a billion times more in the observable universe. Recently, the LIGO experiment detected gravitational wave signals from collisions between neutron stars at cosmological distances. It is now thought that such collisions produce the precious gold that is forged into wedding bands. The moral of this story is that physicists were able to imagine something new in the universe at large and search for it in the sky by following insights gained from laboratory experiments on Earth.

How to Search for Life as We Don't Know It, Avi Loeb, Scientific American

Hot and humid The surface of a Hycean planet as interpreted by an artist. (Courtesy: Amanda Smith, University of Cambridge).

Topics: Astronomy, Astrophysics, Astrobiology, Exoplanets, Space Exploration

Hot, ocean-covered exoplanets with hydrogen-rich atmospheres could harbor life and may be more common than planets that are Earth-like in size, temperature, and atmospheric composition. According to astronomers at the University of Cambridge, UK, this newly defined class of exoplanets could boost the search for life elsewhere in the universe by broadening the search criteria and redefining which biosignatures are important.

Astronomers define the habitable or “Goldilocks” zone as the region where an exoplanet is neither too close nor too far from its host star to have liquid water on its surface – water being the perfect solvent for many forms of life. Previous studies of planetary habitability have focused primarily on searching for Earth-like exoplanets and evidence that they could harbor the kind of chemistry found in life on Earth. However, it has so far proven difficult to detect atmospheric signatures from Earth-like planets orbiting Sun-like stars.

Potentially habitable mini-Neptunes

Larger exoplanets are easier to detect than smaller, Earth-sized ones, and exoplanets around 1.6‒4 times bigger than the Earth, with masses of up to 15 Earth masses and temperatures that in some cases exceed 2000 K, are relatively common. These planets are known as mini-Neptune's as they are similar to the ice giant planets in our solar system.

Previous studies suggested that the high pressures and temperatures beneath these planets’ hydrogen-rich atmospheres were incompatible with life. However, based on their analysis of an exoplanet called K2-18b, exoplanet scientist Nikku Madhusudhan and colleagues at Cambridge say that life could, in fact, exist on a subset of mini-Neptunes that meet specific criteria.

This subset, which the researchers dub “Hycean” (hydrogen + ocean) planets, consists of planets that have radii up to 2.6 times larger than Earth’s and are capable of harboring vast oceans under atmospheres dominated by molecular hydrogen and water vapor. Such oceans could cover the whole planet and reach depths greater than the Earth’s oceans, and the researchers say that the conditions within them could be compatible with some forms of Earth-based microbial life. Hycean planets tidally locked with their host star could also exhibit habitable conditions on their permanent night side.

Astronomers define new class of potentially habitable ocean worlds, Chaneil James, Physics World

Topics: Astrobiology, Biology, Chemistry, Cosmology

The origin of life is one of the great unanswered questions in science. One piece of this puzzle is that life started on Earth 4.5 billion years ago, just a few hundred million years after the formation of the Solar System, and involved numerous critical molecular components. How did all these components come to be available so quickly?

One potential explanation is that the Earth was seeded from space with the building blocks for life. The idea is that space is filled with clouds of gas and dust that contain all the organic molecules necessary for life.

Indeed, astronomers have observed these buildings blocks in interstellar gas clouds. They can see amino acids, the precursors of proteins, and the machinery of life. They can also see the precursors of ribonucleotides, molecules that can store information in the form of DNA.

But there is another crucial component for life – molecules that can form membranes capable of encapsulating and protecting the molecules of life in compartments called protocells. On Earth, the membranes of all cells are made of molecules called phospholipids. But these have never been observed in space. Until now.

First evidence of cell membrane molecules in space, Physics arXiv blog, Astronomy

The mysterious object ‘Oumuamua passed through our solar system in 2017. Loeb has suggested it could have been sent by extraterrestrials. (Credit: European Southern Observatory/Kornmesser)

Topics: Astrobiology, Biology, Cosmology, SETI

Life, for all its complexities, has a simple commonality: It spreads. Plants, animals, and bacteria have colonized almost every nook and cranny of our world.

But why stop there? Some scientists speculate that biological matter may have proliferated across the cosmos itself, transported from planet to planet on wayward lumps of rock and ice. This idea is known as panspermia, and it carries a profound implication: Life on Earth may not have originated on our planet.

In theory, panspermia is fairly simple. Astronomers know that impacts from comets or asteroids on planets will sometimes eject debris with enough force to catapult rocks into space. Some of those space rocks will, in turn, crash into other worlds. A few rare meteorites on Earth are known to have come from Mars, likely in this fashion.

“You can imagine small astronauts sitting inside this rock, surviving the journey,” says Avi Loeb, an astrophysicist at Harvard University and director of the school’s Institute for Theory and Computation. “Microbes could potentially move from one planet to another, from Mars to Earth, from Earth to Venus.” (You may recognize Loeb’s name from his recent book Extraterrestrial: The First Sign of Intelligent Life Beyond Earth, which garnered headlines and criticism from astronomers for its claim that our solar system was recently visited by extraterrestrials.)</p>

Loeb has authored a number of papers probing the mechanics of panspermia, looking at, among other things, how the size and speed of space objects might affect their likelihood of transferring life. While Loeb still thinks it’s more likely that life originated on Earth, he says his work has failed to rule out the possibility that it came from somewhere else in space.

Did Life On Earth Come From Outer Space? Nathaniel Scharping, Discover Magazine

Artist's conception of GN-z11, the earliest known galaxy in the universe. Credit: Pablo Carlos Budassi Wikimedia (CC BY-SA 4.0)

Topics: Astrobiology, Evolution, Existentialism, Exoplanets

About 15 million years after the big bang, the entire universe had cooled to the point where the electromagnetic radiation left over from its hot beginning was at about room temperature. In a 2013 paper, I labeled this phase as the “habitable epoch of the early universe.” If we had lived at that time, we wouldn’t have needed the sun to keep us warm; that cosmic radiation background would have sufficed.

Did life start that early? Probably not. The hot, dense conditions in the first 20 minutes after the big bang produced only hydrogen and helium along with a tiny trace of lithium (one in 10 billion atoms) and a negligible abundance of heavier elements. But life as we know it requires water and organic compounds, whose existence had to wait until the first stars fused hydrogen and helium into oxygen and carbon in their interiors about 50 million years later. The initial bottleneck for life was not a suitable temperature, as it is today, but rather the production of the essential elements.

Given the limited initial supply of heavy elements, how early did life actually start? Most stars in the universe formed billions of years before the sun. Based on the cosmic star formation history, I showed in collaboration with Rafael Batista and David Sloan that life near sunlike stars most likely began over the most recent few billion years in cosmic history. In the future, however, it might continue to emerge on planets orbiting dwarf stars, like our nearest neighbor, Proxima Centauri, which will endure hundreds of times longer than the sun. Ultimately, it would be desirable for humanity to relocate to a habitable planet around a dwarf star like Proxima Centauri b, where it could keep itself warm near a natural nuclear furnace for up to 10 trillion years into the future (stars are merely fusion reactors confined by gravity, with the benefit of being more stable and durable than the magnetically confined versions that we produce in our laboratories).

When Did Life First Emerge in the Universe? Avi Loeb, Scientific American

Topics: Astrobiology, Astronomy, Cosmology, SETI

I would extend his theme to cover something that comes naturally to us all, which I’ll call Pseudo-exceptionalism—the unearned conviction that we are exceptional, superior to others because we were born...us.

We simply assume that we’re kinder, more honest, more realistic, more wholesome than those around us. After all, we’re married to ourselves for life, so we make accommodations: We cut ourselves slack. We’re fast to forgive ourselves. When challenged, we’re much better at making our case than our opponent’s. We spot injustices to ourselves far faster than we spot our injustices to others.</em>

Why Some People (Maybe Even Us) Think They're So Special
… and what to do about it. Jeremy E. Sherman Ph.D., MPP, Psychology Today

It is presumptuous to assume that we are worthy of special attention from advanced species in the Milky Way. We may be a phenomenon as uninteresting to them as ants are to us; after all, when we’re walking down the sidewalk we rarely if ever examine every ant along our path.

Our sun formed at the tail end of the star formation history of the universe. Most stars are billions of years older than ours. So much older, in fact, that many sunlike stars have already consumed their nuclear fuel and cooled off to a compact Earth-size remnant known as a white dwarf. We also learned recently that of order half of all sunlike stars host an Earth-size planet in their habitable zone, allowing for liquid water and for the chemistry of life.

Since the dice of life were rolled in billions of other locations within the Milky Way under similar conditions to those on Earth, life as we know it is likely common. If that is indeed the case, some intelligent species may well be billions of years ahead of us in their technological development. When weighing the risks involved in interactions with less-developed cultures such as ours, these advanced civilizations may choose to refrain from contact. The silence implied by Fermi's paradox (“Where is everybody?”) may mean that we are not the most attention-worthy cookies in the jar.

Why Do We Assume Extraterrestrials Might Want to Visit Us? Avi Loeb, Scientific American

Topics: Astrobiology, Astronomy, Astrophysics, SETI

Cultural references: The post title refers to NC A&T Alumni, and Civil Rights icon Reverend Jesse Jackson's appearance on Saturday Night Live, and the Wow! signal. Personal note: This signal appeared on the same day my granddaughter was born.

<p>On April 29, 2019, the Parkes Radio Telescope in Australia began listing to the radio signals from the Sun’s nearest neighbor, Proxima Centauri, just over 4 lightyears away. The telescope was looking for evidence of solar flares and so listened for 30 minutes before retraining on a distant quasar to recalibrate and then pointing back.

In total, the telescope gathered 26 hours of data. But when astronomers analyzed it in more detail, they noticed something odd — a single pure tone at a frequency of 982.02 MHz that appeared five times in the data.

The signal was first reported last year in The Guardian, a British newspaper. The article raised the possibility that the signal may be evidence of an advanced civilization on Proxima Centauri, a red dwarf star that is known to have an Earth-sized planet orbiting in its habitable zone.

But researchers have consistently played down this possibility saying that, at the very least, the signal must be observed again before any conclusions can be drawn. Indeed, the signal has not been seen again, despite various searches.

Now Amir Siraj and Abraham Loeb from Harvard University in Cambridge, Massachusetts, have calculated the likelihood that the signal came from a Proxima Centauri-based civilization, even without another observation. They say the odds are so low as to effectively rule out the possibility — provided the assumptions they make in their calculations are valid.</p>

Why The Recent Signal That Appeared to Come From Proxima Centauri Almost Certainly Didn't, Physics arXiv Blog, Discovery Magazine

This artist’s concept shows a hypothetical planet covered in water around the binary star system of Kepler-35A and B. The composition of such water worlds has fascinated astronomers and astrophysicists for years. (Image by NASA/JPL-Caltech.)

Topics: Astronomy, Astrobiology, Astrophysics, Cosmology, Exoplanets

Out beyond our solar system, visible only as the smallest dot in space with even the most powerful telescopes, other worlds exist. Many of these worlds, astronomers have discovered, may be much larger than Earth and completely covered in water — basically ocean planets with no protruding land masses. What kind of life could develop on such a world? Could a habitat like this even support life?

A team of researchers led by Arizona State University (ASU) recently set out to investigate those questions. And since they couldn’t travel to distant exoplanets to take samples, they decided to recreate the conditions of those water worlds in the laboratory. In this case, that laboratory was the Advanced Photon Source (APS), a U.S. Department of Energy (DOE) Office of Science User Facility at the DOE’s Argonne National Laboratory.

What they found — recently published in Proceedings of the National Academy of Sciences — was a new transitional phase between silica and water, indicating that the boundary between water and rock on these exoplanets is not as solid as it is here on Earth. This pivotal discovery could change the way astronomers and astrophysicists have been modeling these exoplanets, and inform the way we think about life evolving on them.

Dan Shim, associate professor at ASU, led this new research. Shim leads ASU’s Lab for Earth and Planetary Materials and has long been fascinated by the geological and ecological makeup of these distant worlds. That composition, he said, is nothing like any planet in our solar system — these planets may have more than 50% water or ice atop their rock layers, and those rock layers would have to exist at very high temperatures and under crushing pressure.

Beneath the surface of our galaxy’s water worlds, Andre Salles, Argonne National Laboratory