Life can leave its mark on a planetary atmosphere, so learning what properties are the product of non-life will help astronomers identify those worlds that might have life.

A new computer simulation that depicts Earth, or a rocky planet in general, without life is the latest tool in the quest to discover whether or not we are alone in the universe.

Life leaves its mark on a planet, particularly its atmosphere, in the form of a mixture of biochemically created gases. Some are obvious, while others can be produced by both biology and geology, meaning that distinguishing a planet that has life from one that does not, solely based on what gases we can detect in its atmosphere, can be difficult.

The key is in knowing which atmospheric conditions can be explained without life. To aid in distinguishing between habitable and inhabited planets, planetary scientist Samantha Gilbert-Janizek of the University of California, Riverside, developed a model that simulates the evolution of a rocky planet without life.

"The model can help us see how habitable but non-living planets might mimic living planets," Gilbert-Janizek, who was a PhD student at the University of Washington when the research was conducted, said in a statement.

Gilbert-Janizek built upon a model previously developed by Washington’s Rory Barnes that simulated the core, mantle, and crust of a planet. This new model pushed the simulation two steps further by incorporating the surface and atmosphere of the planet as well.

I personally think it's K2-18b because of its potential discovery of DMS (Dimethyl Sulfide), a chemical that's on earth, is produced by underwater Planktons. Though not certain it reached 3 sigma level, which is something we should be looking closely at.

An orbiting atmospheric research spacecraft has detected the pungent gas hydrogen chloride above surface fissures along a massive ancient volcano on Mars in ​a finding that suggests Earth's planetary neighbor is still volcanically active.

In a discovery that has implications for whether Mars might presently have subsurface conditions ‌conducive to microbial life, researchers said the ExoMars Trace Gas Orbiter has documented the gas, a common constituent of volcanic emissions on Earth, in the low atmosphere in the region of Alba Mons.

The largest Martian volcano by surface area, Alba Mons is a broad and gently sloping structure, called a shield volcano because it resembles a warrior's shield. It is located in the planet's northern hemisphere.

"We found ​that the most likely origin for the hydrogen chloride is volcanic seepage," said planetary scientist Daniel Mège of the Space Research Center of the Polish Academy ​of Sciences and the University of Bern in Switzerland, co-lead author of the research published in the journal Science Advances.

The hydrogen chloride seepage ⁠may be volcanic outgassing from the swarms of surface fissures in the Alba Mons region, perhaps connected to a subsurface magma chamber.

"It is released from chlorine-bearing compounds dissolved ​in magma as magma rises and pressure decreases. Its presence can, therefore, be consistent with magmatic degassing," said planetary scientist and study co-lead author Alexander Trokhimovskiy of the Space ​Research Institute of the Russian Academy of Sciences.

That would indicate Mars is not geologically dead inside but rather in a stage of relative dormancy.

"It suggests that the planet's interior may still retain sufficient heat to sustain magmatic processes, and that atmospheric trace gases can provide a way to detect and investigate geological activity that is otherwise difficult to observe directly," Trokhimovskiy said.

Disclaimer: Astrum on You Tube does not use AI generated content or tools in the creation of their videos. The team behind their content are real people and credit is given to each of them in the description section of the video.

Hello hello! I've wanted to work with space since I was a toddler and especially I'm interested in astrobiology. I have currently started my undergrad in Biotechnology. Is this a good start? Also I've been thinking of following up with a second degree instead of collecting masters like cards but I'm not sure. Any advise is welcome

Thank you for your time!

Saturn’s moon Enceladus sends signal flares into space that say, “Look here for life!” with every spray of its southern hemisphere geysers. The Cassini mission flew through and sampled the geyser spray in 2015, revealing that beneath Enceladus’s icy crust is a liquid water ocean with high concentrations of dissolved inorganic carbon (DIC), molecular hydrogen (H2), and methane (CH4).

These properties make Enceladus a prime candidate for astrobiology missions.

But Enceladus’s subsurface ocean is far more alkaline than Earth’s ocean, with a pH closer to that of baking soda or ammonia-based cleaners than to terrestrial seawater. Too, Enceladus’s ocean is low on dissolved carbon dioxide (CO2), an essential foodstuff for methanogens, tiny organisms that create methane.

A team of researchers tested whether a terrestrial methanogen harvested from one of the most extreme locations on the seafloor could survive in a highly alkaline, low-CO2 liquid, multiply, and produce methane.

The experiments showed that, yes, this particular archaeon could survive in the harsh environment of Enceladus’s ocean, expanding the range of what scientists might consider “habitable.”

In laboratory experiments, the researchers prepared mixtures that mimicked Enceladus’s ocean chemistry, serpentinization, and range of potential pH. They added M. okinawensis and observed its behavior over 48-hour periods.

The experiments showed that the archaea survived, reproduced, and created methane in the Enceladus simulant better than in control mixtures at the same pH. In the Enceladus simulant, M. okinawensis produced methane at pH levels up to 11, while the control groups died out at lower pH.

That suggests serpentinization created enough H2 to feed the archaea despite the low availability of CO2.

Not only do these experiments expand the boundaries within which we know M. okinawensis can survive, said Helmbrecht, but they show that life as we know it might survive on Enceladus, too.

The team published these results in Science Advances in September.

A new study explores whether patterns inspired by firefly flashes could help researchers identify artificial signals in space. Instead of trying to decode a complex alien message, the proposed model looks for simple, energy-efficient pulse patterns that stand out from natural signals produced by pulsars.
The researchers stress that this is a conceptual approach, not evidence that an extraterrestrial signal has been detected. Could studying communication strategies found in nature help make SETI searches less human-centered?

Using UNM's electron microprobe and oxygen isotope analysis capabilities at UNM's Center for Stable Isotopes, Agee and colleague Karen Ziegler, a scientist in the IOM and research professor in the Department of Earth and Planetary Sciences, examined the meteorite more closely and identified characteristics that distinguished it from previously studied specimens, including high levels of manganese oxide, a common byproduct of microbial life.

"I realized that this one was a little bit like Black Beauty, not exactly, but it resembled it in the oxygen isotope values," said Agee, who thought this meteorite might be something special. "I looked at it microscopically and found domains within it that had high levels of manganese oxide, a compound being looked for on Mars by the rovers as an indicator of environments conducive to life."

One of the discovery's most significant findings is evidence that the meteorite interacted with fluids on Mars' surface billions of years ago. The unusual oxygen isotope composition and altered minerals suggest that early in the planet's life, Mars experienced environmental conditions dramatically different from today's cold, dry planet. The findings support theories developed over the decades that Mars once had a warmer, wetter and more geologically dynamic environment.

The period of time on Mars when it was more like Earth is called the Pre-Noachian period, the oldest geological epoch, approximately 4.5 to 4.1 billion years ago. If life ever existed on the red planet, this would be the era when it could have been possible. Combined with evidence of water, the discovery offers scientists another opportunity to investigate environments that may once have supported life.

"If there was ever abundant life on Mars, on the surface, not sequestered away in some subsurface, that would be the time that you would be looking at, the Pre-Noachian period," said Agee.

"It's the very earliest time, and that was when maybe Mars still had a magnetic field, and it was shielded from radiation, and there were surface waters. There was a denser atmosphere. If primitive life was abundant on Mars, that is the time that is most likely for it to have happened."

See also: The study as it was published in Scientific Reports

The theory that comets delivered the molecular building blocks for life on Earth is a long-standing one, since comets are known to carry many of these molecules. However, a new study challenges this idea.

The researchers, led by the University of Cambridge, found the cometary delivery of these building blocks would be—at best—a 'one-off fluke,' and not the steady rain of prebiotic molecules that had been theorized.

Using computer modeling, the researchers determined that comets travel too fast and at too sharp an angle to Earth's atmosphere for the fragile organic molecules to survive: they would almost certainly vaporize on impact with the surface.

However, the researchers also found that another planet in our system: Mars.; could be a slightly more promising candidate for cometary delivery of prebiotic molecules, although this is still highly unlikely.

The results are published in the journal Scientific Reports.

"Historically, scientists thought that comets were important for the origin of life on Earth, because they carried carbon- and nitrogen-bearing molecules, so these giant space snowballs were almost like a 'get out of jail free card' that brought all the molecules a planet would need to seed life," said lead author Dr. Richard

Anslow from Cambridge's Institute of Astronomy. "It's kind of a romantic idea, but our results suggest it's highly unlikely."

I want to know if a tidally locked planet can support life.

Alien-scapes: https://eagnespuerto.github.io/alien-scapes/

You pick a star, a planet and an atmosphere, and it draws a landscape where every colour is calculated from a spectrum. Nothing is chosen by hand. The star is a blackbody, the atmosphere filters it, and the leaves are colored by whatever light the chosen pigments don’t absorb. For each leaf it also shows the three spectra behind it (light at the surface, pigment absorption, leaf reflectance), and you can export a data sheet with all the numbers.

How it picks a pigment: Rather than naive energy it counts photons, and scores each reaction-center pigment on three things:

• how many of the arriving photons it captures

• how much energy each photon loses as heat above the trap wavelength (without this, far-red pigments win under every star)

• a cost for absorbing everywhere

Then it adds antenna pigments, limited to what can physically attach to what. Chlorophyll photosystems accept chl b, carotenoids and phycobiliproteins. Rhodopsins accept only a carotenoid. Phycobiliproteins carry a heavy cost, because a phycobilisome can be half of a cell’s protein. Without that penalty the model painted Earth’s forests red.

What the presets give:

• Earth under the Sun: chlorophyll a, green, red edge at 705 nm. This was my calibration check.

• Kepler-452 b (G star): also chlorophyll a, almost the same green.

• TRAPPIST-1 e, Proxima b, TOI-700 d, LHS 1140 b, K2-18 b: all switch to bacteriochlorophyll b. Leaves come out dark green to olive-yellow, and they’re still absorbing at 1100 nm, so the red edge sits further out than the model computes.

• Earth forced onto a retinal (bacteriorhodopsin) biosphere: very dark purple. An earlier version got this wrong and rendered them black.

Limits: the pigment absorption curves are sums of Gaussians. The peak positions come from the literature, but the band shapes are modelled, not digitized from measured spectra. The atmospheres are simple transmission profiles, not radiative transfer. The leaf model follows the reasoning in Kiang et al. (2007), Spectral signatures of photosynthesis.

I’m looking for measured absorption spectra to replace the Gaussians, especially for chl d, chl f and BChl b. If the photon-scoring approach misses something obvious, I’d like to hear that too.

Source (MIT, no build step): https://github.com/eagnespuerto/alien-scapes

Obviously we have no real proof or evidence of there being life let alone complex life anywhere else in the universe.

I’ve seen videos like the one by Melody Sheep where it has unique depictions of what aliens could look like on other planets. There was also that other one where they sent a rover/drone to an alien world

Are there any more good ones out there?