The original post: /r/aliens by /u/showmeufos on 2024-10-07 17:26:11.
On the VETTED podcast several days ago Professor Simon Holland made some statements regarding rumors that JWST has detected bio-signatures and techno-signatures on the same planet. Depending on the signature(s) detected, this could be a very strong signal for "detection of an intelligent species on an exo-planet." At the time of this posting the discussion of that exchange is today's #1 most upvoted post on r/aliens.
Contrary to the prior rumors about detecting an "object" or "city lights," things that JWST is not technically capable of doing, the claim(s) in this exchange discuss JWST detecting chemical signatures in the atmospheres of an exoplanet that support evidence of life or technology being present on the exoplanet. Unlike the prior rumors of the "object" headed towards earth and the detection city lights, which are almost certainly false based on JWST capabilities, detecting chemicals in this manner is something JWST is actually capable of doing and publicly does do in it's search for life elsewhere. So, such a detection of this type of plausible.
Summarizing Professor Simon Holland's claims on the VETTED podcast below:
- He spoke to a contact who said JWST had found a bio-signature and techno-signature of life. Those signatures were found using spectrum analysis of the chemicals in the atmospheres of transiting exoplanets.
- The contact claimed that the bio-signature and techno-signature were both on the same planet. "it's the same place."
This piqued my interest as I've been following the detection of exo-signatures quite closely for the past several years. The most notable paper on detection of exo-signatures came out last fall, "Carbon-bearing Molecules in a Possible Hycean Atmosphere," and the lead professor on it is from Cambridge: Professor Nikku Madhusudhan. The major detection in that paper was of dimethyl sulfide (DMS) on an exo-planet K2-18b. DMS is a strong biosignature of life. The detection, however, a low-confidence detection. There were many press reports on this finding, and further work is being done to try to confirm the finding, also by Nikku Madhusudhan.
Given Professor Nikku Madhusudhan is the one who made the finding of DMS on K2-18b, it's likely his team would also be involved in any further exoplanet biosignature detections. He has been very active publishing research in 2024 -- they're clearly very busy at work. Can we find any potential candidate systems in Professor Nikku Madhusudhan's research as published thus far that might explain the rumor on the VETTED podcast?
Actually, yes, potentially we can. But it's not as exciting as we all here in r/aliens hope(s)...
The same professor as the K2-18b DMS detection, Professor Nikku Madhusudhan, has published another paper this year which received far less press coverage on planets in the TOI-270 system. The paper is titled "Possible Hycean conditions in the sub-Neptune TOI-270 d" and can be read in full at that link. Of particular interest in that paper are the two planets in the system: TOI-270b and TOI-270d.
There's some important terminology to know here: the primary one is "hycean world," which is a hypothetical type of exoplanet that features a liquid water ocean underneath a hydrogen-rich atmosphere. The term hycean is a portmanteau of hydrogen and ocean. Professor Nikku Madhusudhan's team thinks this type of world is a high-probability candidate for supporting life so spends a lot of time looking for worlds of this type. There's a great paper from this team titled "The Hycean Paradigm in the Search for Life Elsewhere" that discusses this type of planet and why it's relevant to the search for life.
Second, we need to know some molecular annotations to understand this paper:
- "CH4" is the molecular annotation for "methane"
- "CO2" is the molecular annotation for "carbon dioxide"
- "NH3" is the molecular annotation for "ammonia"
- "H2" is the molecular annotation for "hydrogen 2"
- "H2O" is the molecular annotation for "water"
- "HCN" is the molecular annotation for "hydrogen cyanide," formerly known as "prussic acid"
- "CS2" is the molecular annotation for "Carbon disulfide." The compound is commonly used in organic chemistry as a building block, as well as a non-polar industrial and chemical solvent.
- "C2H6" is the molecular annotation for "ethane." Ethane is a naturally occurring organic chemical compound with chemical formula C2H6. At standard temperature and pressure, ethane is a colorless, odorless gas. Like many hydrocarbons, ethane is isolated on an industrial scale from natural gas and as a petrochemical by-product of petroleum refining.
The paper's conclusion section discusses which gasses were detected on TOI-270d and what the implications of that are:
TOI-270 d has been predicted to be a candidate Hycean world (Madhusudhan et al., 2021), with a potentially habitable ocean underneath a H2-rich atmosphere. The planet’s atmosphere was first observed with HST (Mikal-Evans et al., 2023), showing evidence of H2O in a H2-rich atmosphere. The present NIRSpec spectrum, leading to detections of CH4 and CO2 at high significance, as well as the non-detection of NH3, support the interpretation of TOI-270 d as a Hycean planet. Similarly to what was observed for K2-18 b (Madhusudhan et al., 2023b), this composition cannot be explained by a Neptune-like deep H2-rich atmosphere, but it is consistent with that of a warm Hycean world, as predicted in Madhusudhan et al. (2023a).
... paper goes on to say ...
We also find evidence of CS2 in the atmosphere of TOI-270 d. This is of particular interest given that CS2 is a predicted biosignature gas (Domagal-Goldman et al., 2011; Seager et al., 2013; Madhusudhan et al., 2021). Additionally, C2H6, for which we find potential hints, is a predicted indicator of photochemical processes involving CH4 and other organic molecules, including several gases of biological origin (Domagal-Goldman et al., 2011; Catling et al., 2018; Schwieterman et al., 2018). However, it is important to note that, in comparison to DMS that was nominally inferred for K2-18 b (Madhusudhan et al., 2023b), these molecules have alternative abiogenic sources (Rushdi & Simoneit, 2005; Domagal-Goldman et al., 2011; Catling et al., 2018; Schwieterman et al., 2018). Upcoming observations could allow more robust inferences of CS2 and C2H6 in the atmosphere of TOI-270 d at a higher significance – if they are indeed present.
So to summarize, this paper is saying:
- Based on spectrum analysis they believe TOI-270d is a hycean world, which is a type of world likely capable of supporting life
- They also found CS2 ("carbon disulfide") in the atmosphere, which is a compound that is considered an organic building block and is a predicted biosignature.
- They also found hints of C2H6 ("ethane") which is a potential techno-signture.
- The paper notes, "However, it is important to note that, in comparison to DMS that was nominally inferred for K2-18 b (Madhusudhan et al., 2023b), these molecules have alternative abiogenic sources." This means that these molecules can form without life - via natural, non-life (and non-technology) based processes. That means that these are NOT strong signatures of life. BUT, they could be life.
This paper actually fits pretty strongly with the claims made by Professor Simon Holland on the VETTED podcast that JWST had detected potential bio-signatures and techno-signatures on the same planet. This is not a secret paper, you don't need some secret retired-ESA contact to find it, it is out in the world and you can read it right now in full right here: "Possible Hycean conditions in the sub-Neptune TOI-270 d" If you're interested in other work (which I do suggest reading, he publishes great work!) from Professor Nikku Madhusudhan you can view that here.
The takeaway from this is that Professor Simon Holland *might* be simply referring to someone who was referencing this published paper, which is a low-confidence low-probability detection of potential life on TOI-270d based on atmospheric analysis from JWST. It fits quite nicely with his statements. This type of thing warrants further research, observation(s) from JWST, etc., but is not anything that we should be getting excited abo...
Content cut off. Read original on https://old.reddit.com/r/aliens/comments/1fydam2/professor_holland_discusses_rumors_that_jwst/
