astrobiology – Geobites

September 2, 2022September 2, 2022

We’re Here Because We’re Here Because… of Chance?

A painting of many stars as in a night sky, surrounded by planets, with their orbits drawn out.

Featured image: An artist’s depiction of many, many possible planets. This image was created by the European Southern Observatory (ESO).

Paper: Tyrrell, T. Chance played a role in determining whether Earth stayed habitable. Commun Earth Environ 1, 61 (2020). https://doi.org/10.1038/s43247-020-00057-8

Have you ever stayed up at night and wondered, why am I here? Or, more broadly, why are we here, including all living things on this Earth? Don’t worry, you’re not alone, and scientists like Professor Toby Tyrrell of the University of Southampton (UK) have been trying to answer these questions using the scientific method.

His conclusion? It may have just been the luck of the draw. After all, if we weren’t here in the first place, we couldn’t wonder why we were. (Scientists call this the weak anthropic principle.)

Climate scientists often describe their models as alternate (climate) histories. Tyrrell’s 2020 paper takes this idea to its ultimate conclusion, running 100 alternate climate histories on 100,000 randomly generated planets within the habitable zone of their randomly generated stars for 3 billion years. The question he’s trying to help answer is this: how likely was it that the Earth’s climate stayed habitable for the 4 billion years between the evolution of the first prokaryotic cells and us? Was it due to some intrinsic properties of planet Earth, or of life, or was it merely chance?

February 25, 2022February 25, 2022

To understand Mars, scientists study Earth – but is this enough?

Featured Image: Top: Valley of the Moon, Atacama Desert, San Pedro, Chile, Earth. Image courtesy Alf Igel. Bottom: Jezero Crater, Syrtis Major Quadrangle, Mars. Image courtesy Kevin M. Gill.

Paper: Gradient studies reveal the true drivers of extreme life in the Atacama Desert

Authors: D. Boy, R. Moeller, L. Sauheitl, F. Schaarschmidt, S. Rapp, L. van den Brink, S. Gschwendtner, R. Godoy Borquez, Francisco J. Matus, M. A. Horn, G. Guggenberger, J. Boy

Space. The final frontier. Or is it? Boy and colleagues are not presenting the voyages of the Starship Enterprise, rather the clever investigation of scientists on Earth. Their continuing mission: to understand the development of life in extreme environments, and how certain places on Earth geologically represent Mars and other planet analogues. While Boy and colleagues are limited on intergalactic travel, their recent work clearly the defines expectations, inferences, and consequences of using a site on Earth as a replacement for another planet. They conclude that the nearby climate and environment surrounding these analogue locations may lead to inaccurate comparisons, by altering soil moisture and salt content, for example.

February 17, 2022February 17, 2022

Martian Past Revealed by New Analysis of 4 Billion-year-old Meteorite

Paper: Organic synthesis associated with serpentinization and carbonation on early Mars

Authors: Steele A, Benning LG, Wirth R, Schreiber A, Araki T, McCubbin FM, Fries MD, Nittler LR, Wang J, Hallis LJ, and Conrad PG.

The discovery of organic carbon in Martian meteorites has fueled scientific debates for more than four decades. Could these molecules be the chemical residue of Martian life?

August 25, 2021August 25, 2021

Mysterious methane on Mars

Featuring image: northern rim of Gale Crater viewed by Curiosity. NASA/JPL-Caltech/MSSS, public domain (CC0)

Paper: Day-night differences in Mars methane suggest nighttime containment at Gale crater

Authors: C. R. Webster, P. R. Mahaffy, J. Pla-Garcia, S. C. R. Rafkin, J. E. Moores, S. K. Atreya, G. J. Flesch, C. A. Malespin, S. M. Teinturier, H. Kalucha, C. L. Smith, D. Viúdez-Moreiras and A. R. Vasavada

Methane is a gas often connected to life on Earth. NASA’s Mars rover reported the detection of methane, but discrepancies with other missions puzzled researchers. Is there methane on Mars or not? A new study tries to answer this question in a windy way.

Methane is a possible biosignature for extraterrestrial life and therefore, one of the goals of the Mars rover Curiosity was to search for methane. Curiosity was able to detect varying amounts of this gas over the years, but the existence of methane in the Martian atmosphere could not be confirmed by analysis from satellites. Now, Christopher Webster and his group were able to explain the variations as well as the discrepancy between ground-based and satellite analysis by developing a detailed model of the wind systems at Gale crater.

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August 19, 2021August 20, 2021

The Search for Life on Mars Begins on Earth

Self portrait of NASA's Curiosity rover. Curiosity is currently climbing Moount Sharp, which can be seen rising on the right-hand side of the image, seeking signs that Mars have been a habitable planet in the past.

Article: Fatty Acid Preservation in Modern and Relict Hot-Spring Deposits in Iceland, with Implications for Organics Detection on Mars

Authors: Williams, Amy J., Kathleen L. Craft, Maëva Millan, Sarah Stewart Johnson, Christine A. Knudson, Marisol Juarez Rivera, Amy C. McAdam, Dominique Tobler, and John Roma Skok.

The quest to find signs of life on Mars is one of the greatest scientific challenges of our time. For some researchers, the quest is a chemical one. A search for the biomolecular remains of life that may have lived when Mars was warmer and wetter billions of years ago. However, finding and recognizing molecular fossils is no easy task, even for a rover as sophisticated as Curiosity. Now, new research from Dr. Amy Williams and her colleagues provides fresh insights into where Mars rovers should look for these fossils, what the signatures may look like, and a simple procedure for how to detect them.

June 27, 2021June 27, 2021

The only way is… down? Groundwater on Mars could support microbial life in the present day

Featured image: A person exploring the rocks of a cave on Earth, Pixabay.

Paper: Earth-like Habitable Environments in the Subsurface of Mars

Authors: J.D. Tarnas, J.F. Mustard, B. Sherwood Lollar, V. Stamenković, K.M. Cannon, J.-P. Lorand, T.C. Onstott, J.R. Michalski, O. Warr.

Mars exploration has been looking “up” recently: the Ingenuity helicopter performed the first powered flight on another planet, and veteran rover Curiosity gave us stunning images from the top of Mount Mercou. But if we want to look for life on Mars, it might be time for us to look down instead. New research suggests that life on present day Mars could be sustained by chemical energy produced through the interaction between water and rocks deep underground, like it is here on Earth.

April 21, 2021April 21, 2021

Oxia Planum: ExoMars 2022 Landing Site

Featured Image: Artist’s impression of ESA’s ExoMars rover ‘Rosalind Franklin’ on the surface of Mars. Credit: ESA.

Paper: Oxia Planum: The Landing Site for the ExoMars “Rosalind Franklin” Rover Mission: Geological Context and Prelanding Interpretation

Authors: Quantin-Nataf et al., 2021

We are entering a new dawn of Mars exploration: Perseverance rover touched down on Mars earlier this year, which marks the start of what will be a decade-long effort to return samples from Mars. In 2022 the European Space Agency (ESA) will launch the ExoMars rover, which will team up with the ExoMars Trace Gas Orbiter (TGO) to find evidence of past or present life on Mars.

April 19, 2021April 20, 2021

Are we star dust?

Paper: Amino acid abundances and compositions in iron and stony‐iron meteorites

Authors: Jamie E. Elsila, Natasha M. Johnson, Daniel P. Glavin, José C. Aponte, Jason P. Dworkin

All known life on Earth relies on amino acids. Many important biomolecules like proteins are made up of them. Scientists were surprised when they found these molecules, which are so strongly connected to living systems, in meteorites. How amino acids form in non-biological systems is still not entirely understood and is closely tied to the question of how life emerged on our young planet.

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November 26, 2020November 26, 2020

It’s LeviOsa, Not LevioSA: The Science Of Levitating Mud On Mars

Featured image: A mud volcano and mud flows in Azerbaijan. Credit: CAS/ Petr Brož/ CC BY-SA 4.0.

Paper: Mud flow levitation on Mars: Insights from laboratory simulations

Authors: Petr Brož et al.,

The Mariner spacecraft’s first images of Mars in the 1960s and 70s showed large volcanoes and flow features, most likely lava or mud. These features were largely interpreted to be lava flows because they look similar to those seen on Earth. However, a 2020 study by Brož et al., shows that mud flows may be more prevalent on Mars than first hypothesized.

November 16, 2020November 17, 2020

New instrument maps and preserves frozen habitats on Earth- and potentially icy worlds

Featured Image: Iceberg in North Star Bay, Greenland by Jeremy Harbeck – NASA, Public Domain

Paper: Subsurface In Situ Detection of Microbes and Diverse
Organic Matter Hotspots in the Greenland Ice Sheet

Authors: Michael J. Malaska, Rohit Bhartia, Kenneth S. Manatt, John C. Priscu, William J. Abbey, Boleslaw Mellerowicz, Joseph Palmowski, Gale L. Paulsen, Kris Zacny, Evan J. Eshelman, and Juliana D’Andrilli

Like the rings of a tree, core samples extracted from glacial ice preserve a unique record of past events. But instead of recording seasonal growth, the ancient ice sheets of Antarctica and Greenland have preserved the conditions of long gone climates and ecosystems. Some sheets have continuously accumulated so much snowfall over the past series of millennia that in some places the ice can reach depths that are miles deep. Analyzing this immense glacial record can inform us about not just the global patterns of climate change, but also the evolution of microbial life on Earth, and maybe even the icy worlds of our Solar System.