The Slow Advance Toward Life Detection

Brian Koberlein earlier this month, on using Earth to predict JWST’s ability to detect signs of life on exoplanets:

The authors then took this to the next level by “roughing up” the data, adding simulated noise to the signal, and then sampling it at lower resolutions. This is similar to the kind of observations JWST would make on an exoplanet light-years away. The goal was to determine if enough data could still be captured to identify atmospheric models, even when the observations are faint and noisy. Sure enough, the signal-to-noise ratio was strong enough to identify many of the molecules for an Earth-like exoplanet within 50 light-years of Earth.

NASA just this week (today, in fact), on JWST detecting atmospheric elements on an exoplanet:

The abundance of methane and carbon dioxide, and shortage of ammonia, support the hypothesis that there may be a water ocean underneath a hydrogen-rich atmosphere in K2-18 b. These initial Webb observations also provided a possible detection of a molecule called dimethyl sulfide (DMS). On Earth, this is only produced by life. The bulk of the DMS in Earth’s atmosphere is emitted from phytoplankton in marine environments.


  1. Also on Monday, Elise Cutts on what qualifies as a life signal JWST could detect anyway:

    If we can observe enough rocky exoplanets, “we’re going to be in a much, much stronger place to understand what a biosignature means,” says Wordsworth. “One really powerful thing that exoplanets give us is statistics.”

    The word “biosignature” may evoke a smoking gun. But, says Krissansen-Totton, “exoplanet life discovery is going to be a gradual accumulation of evidence.”

    Previously here, see the discussion of “lyfe” and questioning some of our assumptions.