home.social

#biosignature — Public Fediverse posts

Live and recent posts from across the Fediverse tagged #biosignature, aggregated by home.social.

  1. Here is a problem that has been quietly gnawing at astronomers for decades.

    The standard approach to detecting #life on other worlds involves scanning #exoplanet #atmospheres for #oxygen, #methane, and #ozone, whose presence is difficult to explain without #biology.

    It's a clever idea, but it carries a hidden flaw. That entire shopping list was written by studying Earth. It is, inevitably, a search for life like us.

    The list of ways that #chemistry alone can accidentally mimic these #biosignature gases is growing faster than the list of new ways to detect life.

    Each new false positive scenario demands even more information about the #planet to rule it out, and there is a genuine question about whether that information can ever be gathered exhaustively.

    But there is a solution.

    #Assembly theory doesn't ask what #molecules are present in an #atmosphere. Instead, it asks how hard they were to make.

    Every molecule can be assigned an assembly index, a minimum number of construction steps required to build it from basic #chemical building blocks.

    Simple molecules are easy to assemble by chance, but truly complex ones, requiring many sequential steps, don't arise without something doing a great deal of deliberate selection.

    That something would then be life itself.

    #astrobiology #astronomy
    phys.org/news/2026-03-life.html

    Paper by Walker et al. (2026): arxiv.org/abs/2603.11086

  2. The #Perseverance press conference panel consists of 5 NASA managers and 1 Mars researcher - so the topic is likely some follow-up to "the
    discovery of a potential #biosignature" in an outcrop reported earlier this year in ntrs.nasa.gov/api/citations/20 while the specific rock to be discussed today was shown in April in science.nasa.gov/resource/meet and mentioned in August in eurekalert.org/news-releases/1 and the O-PTIR #spectroscopy method to hunt for microbial markers was discussed in March in u-tokyo.ac.jp/focus/en/press/z

  3. Astronomers have detected the most promising signs yet of a possible #biosignature outside the solar system, although they remain cautious.

    They have detected the chemical fingerprints of dimethyl sulfide and/or dimethyl disulfide, in the #atmosphere of the #exoplanet K2-18b, which orbits its star in the #habitable zone.

    On Earth, theyare only produced by #life, primarily microbial life such as marine phytoplankton.

    #astronomy #astrobiology
    cam.ac.uk/stories/strongest-hi

  4. The upcoming extremely large telescopes will provide the first opportunity to search for signs of #habitability and #life on non-transiting #terrestrial #exoplanets.

    For the most accessible nearby target, #Proxima Centauri b, we may be able to rule out a sub-Neptune #atmosphere in as little as a single hour of observing, and some #biosignature disequilibrium pairs may be accessible in 10 hours.

    #astronomy #astrobiology
    arxiv.org/abs/2503.08592

  5. We are inching closer and closer to reliably detecting #biosignatures on distant #planets.

    Much of the focus is on determining which chemicals indicate #life's presence.

    But life can also create free energy in a system, and excess energy can create chemical disequilibrium. That's what happened on Earth when life got going.

    Could chemical disequilibrium be a #biosignature?

    #astronomy #astrobiology #exoplanets
    phys.org/news/2023-11-life-eas

    Paper by Young et al. (2023):
    arxiv.org/abs/2311.06083