Mars Might Have Been Covered in Lakes in the Ancient Past

Artist's impression of Mars during the Noachian Era. Credit: Ittiz/Wikipedia Commons

Ever since robotic explorers began visiting the Red Planet during the 1960s and 70s, scientists have puzzled over Mars’ surface features. These included flow channels, valleys, lakebeds, and deltas that appear to have formed in the presence of water. Since then, dozens of missions have been sent to Mars to explore its atmosphere, surface, and climate to learn more about its warmer, wetter past. In particular, scientists want to know how long water flowed on the surface of Mars and whether it was persistent or periodic in nature.

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.

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Perseverance Has Collected Samples from One of the Best Places to Search for Ancient Life on Mars

NASA’s Perseverance rover puts its robotic arm to work around a rocky outcrop called “Skinner Ridge” in Mars’ Jezero Crater. Composed of multiple images, this mosaic shows layered sedimentary rocks in the face of a cliff in the delta, as well as one o... Credit: NASA/JPL-Caltech/ASU/MSSS

Scientists with NASA’s Perseverance Mars rover said today that the rover has collected several “tantalizing” organic rock samples from an ancient river delta on the Red Planet. These samples have now been stowed for a planned future mission that hopes to retrieve the specimens and bring them back to Earth for the first-ever sample return from Mars.

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Alien Artifacts Could Be Hidden Across the Solar System. Here’s how we Could Search for Them.

Galileo Project members (from left: Carson Ezell, Ezra Kelderman, Abby White, Alex and Lily Delacroix) with the audio tower (left), radar spectrum tower (middle) and radar imaging tower (right) behind them on the roof of the Harvard College Observatory.
Galileo Project members (from left: Carson Ezell, Ezra Kelderman, Abby White, Alex and Lily Delacroix) with the audio tower (left), radar spectrum tower (middle) and radar imaging tower (right) behind them on the roof of the Harvard College Observatory. Image credit: The Galileo Project

Do aliens exist? Almost certainly. The universe is vast and ancient, and our corner of it is not particularly special. If life emerged here, it probably did elsewhere. Keep in mind this is a super broad assumption. A single instance of fossilized archaebacteria-like organisms five superclusters away would be all it takes to say, “Yes, there are aliens!” …if we could find them somehow.

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Tidal Heating Could Make Exomoons Much More Habitable (and Detectable)

An artist's illustration of the Kepler 1625 system. The star in the distance is called Kepler 1625. The gas giant is Kepler 1625B, and the exomoon orbiting it is unnamed. The moon is about as big as Neptune, but is a gas moon. Image: NASA, ESA, and L. Hustak (STScI)
An artist's illustration of the Kepler 1625 system. The star in the distance is called Kepler 1625. The gas giant is Kepler 1625B, and the exomoon orbiting it is unnamed. The moon is about as big as Neptune, but is a gas moon. Image: NASA, ESA, and L. Hustak (STScI)

Within the Solar System, most of our astrobiological research is aimed at Mars, which is considered to be the next-most habitable body beyond Earth. However, future efforts are aimed at exploring icy satellites in the outer Solar System that could also be habitable (like Europa, Enceladus, Titan, and more). This dichotomy between terrestrial (rocky) planets that orbit within their a system’s Habitable Zones (HZ) and icy moons that orbit farther from their parent stars is expected to inform future extrasolar planet surveys and astrobiology research.

In fact, some believe that exomoons may play a vital role in the habitability of exoplanets and could also be a good place to look for life beyond the Solar System. In a new study, a team of researchers investigated how the orbit of exomoons around their parent bodies could lead to (and place limits on) tidal heating – where gravitational interaction leads to geological activity and heating in the interior. This, in turn, could help exoplanet-hunters and astrobiologists determine which exomoons are more likely to be habitable.

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Here are the 7 Best Places to Search for Life in the Solar System

If humanity is ever going to find life on another planet in the solar system, it’s probably best to know where to look.  Plenty of scientists have spent many, many hours pondering precisely that question, and plenty have come up with justifications for backing a particular place in the solar system as the most likely to hold the potential for harboring life as we know it.  Thanks to a team led by Dimitra Atri of NYU Abu Dhabi, we now have a methodology by which to rank them.

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What is the Kardashev Scale?

Nikolai Kardashev (1932-2019), Credit: IAU

Are we alone in the Universe? Could there be countless sentient life forms out there just waiting to be found? Will we meet them someday and be able to exchange knowledge? Will we even recognize them as intelligent life forms if/when we meet them, and them us? When it comes to astrobiology, the search for life in the Universe, we don’t know what to expect. Hence why all the speculation and theoretical studies into these questions are so rich and varied!

One such study was conducted by famed Soviet and Russian astrophysicist and radio astronomer Nikolai Kardashev (1932 – 2019). While considering an important question related to the Search for Extraterrestrial Intelligence (SETI) in 1964, Kardashev proposed a classification scheme for ranking a civilization’s development. This would come to be known as the Kardashev Scale, which remains one of the most influential concepts in SETI to this day.

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How to Search for Life as we Don’t Know it

Artist's concept of Earth-like exoplanets, which (according to new research) need to strike the careful balance between water and landmass. Credit: NASA

The fields of extrasolar planet studies and astrobiology have come a long way in recent years. To date, astronomers have confirmed the existence of 4,935 exoplanets in 3,706 star systems, with another 8,709 candidates awaiting confirmation. With so many planets to study, next-generation instruments, and improved data analysis, the focus is transitioning from discovery to characterization. With the James Webb Space Telescope now deployed, these fields are about to advance much farther!

In particular, scientists anticipate that the characterization of planetary atmospheres may lead to the discovery of “biosignatures” – signs we associate with life and biological processes. The challenge will be how to recognize signatures that don’t conform to “life as we know it.” In a recent study, researchers from the School of Earth and Space Exploration (SESE) at Arizona State University (ASU) investigate possible tools for searching for life “as we don’t know it.”

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Does the Entire Planet Have a Mind of its Own?

In a self-described "thought experiment," University of Rochester astrophysicist Adam Frank and colleagues David Grinspoon at the Planetary Science Institute and Sara Walker at Arizona State University use scientific theory and broader questions about how life alters a planet, to posit four stages to describe Earth's past and possible future. Image Credit: (University of Rochester illustration / Michael Osadciw)

What is humanity? Do our minds set us apart from the rest of nature and from the rest of Earth? Or does Earth have a collective mind of its own, and we’re simply part of that mind? On the literal face of it, that last question might sound ridiculous.

But a new thought experiment explores it more deeply, and while there’s no firm conclusion about humanity and a planetary mind, just thinking about it invites minds to reconsider their relationship with nature.

Overcoming our challenges requires a better understanding of ourselves and nature, and the same is true for any other civilizations that make it past the Great Filter.

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Rocky Planets Might Need to be the Right age to Support Life

This artist’s impression shows the planet orbiting the Sun-like star HD 85512 in the southern constellation of Vela (The Sail). This planet is one of sixteen super-Earths discovered by the HARPS instrument on the 3.6-metre telescope at ESO’s La Silla Observatory. This planet is about 3.6 times as massive as the Earth lis at the edge of the habitable zone around the star, where liquid water, and perhaps even life, could potentially exist. Credit: ESO

Extrasolar planets are being discovered at a rapid rate, with 4,531 planets in 3,363 systems (with another 7,798 candidates awaiting confirmation). Of these, 166 have been identified as rocky planets (aka. “Earth-like”), while another 1,389 have been rocky planets that are several times the size of Earth (“Super-Earths). As more and more discoveries are made, the focus is shifting from the discovery process towards characterization.

In order to place tighter constraints on whether any of these exoplanets are habitable, astronomers and astrobiologists are looking for ways to detect biomarkers and other signs of biological processes. According to a new study, astronomers and astrobiologists should look for indications of a carbon-silicate cycle. On Earth, this cycle ensures that our climate remains stable for eons and could be the key to finding life on other planets.

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How to Prevent our Spacecraft From Contaminating Mars

Credit: NASA

Mars has become something of an international playground over the past twenty years. There are currently eleven missions from five space agencies exploring the Red Planet, a combination of orbiters, landers, and rovers. Several additional robotic missions will be leaving for Mars in the next few years, and crewed missions are planned for the 2030s. Because of this increase in traffic, NASA and other space agencies are naturally worried about “planetary protection.”

With this in mind, the National Academies of Sciences, Engineering, and Medicine (NASEM) recently released a new report that identified several criteria for future robotic missions to Mars. These would reduce these missions’ “bioburden” requirements, which are designed to prevent the unintentional contamination of the Red Planet with Earth-based organisms. Specifically, the report considers how Earth organisms would interfere with searches for indigenous life on the planet.

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