# Talk:K2-18b

arXiv:2501.18477, the results find no evidence of carbon dioxide or DMS. Let's see if the results will be accepted for publication. 21 Andromedae (talk) 11:25, 31 January 2025 (UTC)

I also note once the results are published, this article may need a massive rewritten. 21 Andromedae (talk) 13:38, 1 February 2025 (UTC)
Today, two more papers on this planet dropped. One is by none other than Madhusudhan et al., finding evidence for DMS. Another is https://arxiv.org/abs/2504.12030, which analyses absorption lines and finds the Bond albedo of the planet to be far too low (0.17-0.18) for water ocean to exist. AstroChara (talk) 03:47, 17 April 2025 (UTC)
Loads of strange things happen in the Universe as per Prof Catherine Heymans in the BBC article. If I understand the larger context correctly, it's the sheer amount of dimethyl sulphide (DMS) and dimethyl disulphide (DMDS) which really made scientists prick up their ears, abiotic methods notwithstanding. And so we wait for more sigma. kencf0618 (talk) 16:45, 17 April 2025 (UTC)
The problem is the detection paper manipulated statistics to create that detection, and other papers have shown that 1) it really is not a detection, and 2) other substances can also explain the spectra. The general consensus is that the planet's atmosphere has methane, while carbon dioxide is challenged, and the rest is up in the air. AstroChara (talk) 07:01, 7 July 2025 (UTC)

It seems  Cambridge and the JWST are currently finding a few new things on astrobiology about this exoplanets. Maybe this article needs to have a notice that its details can be subject to change as new findings arrive. IapetusCallistus (talk) 13:09, 17 April 2025 (UTC)

I understand that DMS can be created by lightning depending on the constituents of the atmosphere. If so, that is a more parsimonious explanation for DMS than life, but I have not read whether the CU scientists have considered / eliminated this possible cause.198.140.62.1 (talk) 13:13, 17 April 2025 (UTC)
I wasn't talking about putting the information "There is life in this exoplanet". I was just talking about putting a "Notice" that there are new information will likely come up in the next few days. IapetusCallistus (talk) 13:40, 17 April 2025 (UTC)
This is a good idea.
Additionally, this new research work is so poorly received by professional astronomers; I hope we can include all this scepticism here too.
Some useful threads for context:
- https://bsky.app/profile/chrislintott.bsky.social/post/3lmy5sdsv5s27
- https://bsky.app/profile/distantworlds.space/post/3lmzihugafk2x (a thread explaining why the detection is not significant and how the author engaged in statistical hacking to get a 'significant' detection)
- https://bsky.app/profile/chrislintott.bsky.social/post/3lmybrmaq2k27 AstroChara (talk) 06:19, 18 April 2025 (UTC)
One thing that might be worth doing is to write the text as an overview of the various competing claims, rather than adding each new one as a new paragraph. I also kinda wonder if we should rely this much on WP:PREPRINTS. Jo-Jo Eumerus (talk) 08:06, 5 June 2025 (UTC)
That's my thinking as well; this article is quite a mess at the moment, and would really benefit from actually being properly reorganized and presenting all the claims.
Though, I would like to note that basically only one team seems to be pushing for the hycean, often using dubious assumptions. Other teams generally either find it to be consistent with other scenarios (subneptune, magma ocean, etc.) or refute the hycean claim (eg. the Bond albedo preprint, which came out in April). AstroChara (talk) 07:08, 7 July 2025 (UTC)

Exoplanet naming convention dictates that exoplanets should be name based on the the host star and appended with a space and letter representing order of discovery, so "K2-18b" should actually be "K2-18 b", for example.
Spelled correctly by NASA in this catalog: https://science.nasa.gov/exoplanet-catalog/k2-18-b/ 100.4.188.148 (talk) 21:22, 22 April 2025 (UTC)

I agree. This is the convention used by the planetary habitability laboratory at Arecibo which has traditionally set the norm for exoplanet terminology [1]. It is also the convention used by Madhusudhan [2] and their critics [3]. ~ El D. (talk to me) 15:22, 4 June 2025 (UTC)

So, it's that season when I usually update Wikipedia articles. Except that for this one, I wonder if there are objections to including all the publications here. I'd be also inclined to trim the "Discovery and research history" section a bit, as it stands it reads like a back-and-forth. Jo-Jo Eumerus (talk) 13:12, 1 November 2025 (UTC)

No objections from me, a yearly article update is a great thing! I also agree that trimming is a good idea: for example the whole paragraph about a podcast can be simply removed, while other stuff (in year x, in year y) should be trimmed. Artem.G (talk) 21:17, 2 November 2025 (UTC)
To be honest, I think the last paragraph in the lead also needs a heavy rewrite under WP:UNDUE - Ethan Siegel is far from the only researcher to have raised doubts, and "lab experiments that can produce DMS without life" is far from the only objection. Never mind that lab experiments showing that DMS can be produced abiotically do not actually imply that DMS in K2-18b's atmosphere can be explained that way; one would have to consider whether the quantities are plausible, for instance. Jo-Jo Eumerus (talk) 07:58, 6 November 2025 (UTC)
Agree, and at least two sources (5 and 7) are used only in lead. Artem.G (talk) 12:45, 6 November 2025 (UTC)
OK, rewrote the lead and tentatively also deleted the four paragraphs discussed below - WP:NOTCHANGELOG is about software updates, but I think we can extend that logic to research updates on an exoplanet too. Jo-Jo Eumerus (talk) 08:47, 7 November 2025 (UTC)
I suggest otherwise, a policy intended to be used on a specific context can't be applied to a different (and somewhat unrelated) context. Reporting research updates on an exoplanet is what we naturally do in Wikipedia. By the way, i think that the deleted paragraphs should be reinstated. 21 Andromedae (talk) 18:26, 7 November 2025 (UTC)
Research updates are fine, but why they're needed once they are outdated? And one of the paragraphs removed is A podcast on the Planetary Society's website in January 2024 featured NASA astrophysicist Knicole Colón describing some of the scientific results from the observations of K2-18b by JWST. This podcast episode is not notable by itself, and adds nothing useful, so why reinstate it? Artem.G (talk) 18:56, 7 November 2025 (UTC)
That and WP:PROSELINE is a bad style that also lends itself to giving WP:UNDUE weight to each specific study or press release. JoJo Eumerus mobile (main talk) 06:40, 8 November 2025 (UTC)
The thing that I wonder about though is whether astronomy articles enjoy an exemption from Wikipedia:Reliable sources#Preprints - "A study in 2025 with JWST using four new transit observations suggested that while K2-18b might have a water-rich interior, the tentative presence of DMS and methyl mercaptan (CH3SH) can be explained abiotically." for example is a preprint, and I don't think that New Scientist mentioning them on its own is enough to make that concern go away. Jo-Jo Eumerus (talk) 08:05, 6 November 2025 (UTC)
OK, I did the update. Somewhat predictably, the non-DMS aspects of K2-18b had fallen by the wayside. I'd like to remove the last 4 paragraphs of the discovery section (now the biosignatures section) since they are mostly highlighting particular studies and researchers (sometimes preprints) without combining everything into a coherent text. Also, as pointed out by Albergaria et al 2025 and Tennyson & Yurchenko 2025 the news and press releases probably aren't particularly reliable on this topic. Jo-Jo Eumerus (talk) 10:35, 6 November 2025 (UTC)