Last week, scientists using the James Webb Space Telescope (JWST) made an intriguing discovery on a distant exoplanet known as K2-18 b: a potential hint of dimethyl sulfide (DMS), a molecule typically produced by microscopic marine life on Earth. This exoplanet is located approximately 120 light-years away and orbits within the habitable zone of a red dwarf star. It is believed to be a Hycean world, characterized by a steamy, ocean-covered surface with a hydrogen-rich atmosphere.
While the detection of DMS on K2-18 b showed promising results with a statistical confidence of 3-sigma, it was not definitive. This led to widespread speculation about the possibility of finding extraterrestrial life, although not all scientists are convinced. Different experts are now sharing their opinions on the findings, with some cautiously optimistic and others skeptical about the implications. The question remains: could DMS be a sign of life, or is it simply a result of unusual abiotic chemistry under extreme conditions?
In this latest Giz Asks feature, various experts provide their reactions to the discovery, exploring the chemistry involved, the limitations of the data, and what further research is needed to reach a more conclusive understanding. The responses have been edited for clarity.
Oliver Shorttle, a planetary chemist at the University of Cambridge, expressed doubts about the astrobiological significance of the DMS detection on K2-18 b. He highlighted the need to confirm the signal is truly from the planet and determine if it is a biological or non-biological process. Shorttle emphasized that the extreme conditions on K2-18 b make it unlikely to support life, even if DMS is present.
Christopher Glein, a geochemist at the Southwest Research Institute, acknowledged the interesting nature of the new data but cautioned about jumping to conclusions regarding the presence of DMS on K2-18 b. He stressed the importance of further analysis and the need for multiple pieces of evidence to support the existence of life on the planet.
Nikku Madhusudhan, an astrophysicist at the University of Cambridge and lead author of the study, noted that while the discovery moves the needle towards the possibility of life, caution and openness to alternative explanations are crucial. Madhusudhan expressed optimism about the potential for additional data in the coming years to provide more insights.
Ignas Snellen, an astrophysicist at Leiden University, downplayed the significance of the findings, suggesting that the research has been blown out of proportion in the media. Snellen pointed out the uncertainty surrounding the observed spectral features and the need for further investigation into other possible causes besides DMS.
Overall, the debate continues among experts in the field, with differing opinions on the implications of the DMS detection on K2-18 b for the search for extraterrestrial life. Further research and analysis will be essential in determining the true nature of this intriguing discovery. Sumber non-biologis molekul] yang bisa menyebabkan benjolan ini dan menyebutnya selesai. Jika saya adalah wasit, saya akan menghentikan publikasi ini di sana. Tidak ada alasan untuk memanggil astrobiologi, apalagi menyebutnya sebagai terobosan terbesar atau apa pun.”
Sebagian besar wartawan menulis sebuah artikel di mana mereka mengatakan sesuatu seperti “namun, tidak semua ilmuwan yakin…” Saya bisa memberitahu Anda, itu jauh lebih buruk dari itu, tapi sebagian besar dari kita tetap diam. Saya mengerti mengapa, di masa-masa sulit ini, tapi dalam jangka panjang ini akan merugikan astronomi ketika tidak ada yang akan menganggap serius lagi. Anda bisa mengutip saya tentang hal itu.”
Sara Seager
Seorang ilmuwan planet di MIT yang mengkhususkan diri dalam atmosfer planet ekstrasolar.
Karena kemungkinan besar tidak dapat dikonfirmasi baik cara, kita harus hidup dengan apa yang mungkin kita sebut “kandidat planet biosignature.” Planet ini membutuhkan lebih banyak pekerjaan untuk mencapainya. Anda bisa yakin bahwa orang lain sedang bekerja pada cara DMS bisa diproduksi tanpa kehidupan.
Saya menghargai antusiasme orang. Dengan lebih banyak bukti, planet ini dan planet lainnya mungkin “diberkati” sebagai kandidat biosignature, tetapi akan tetap berada dalam kategori kandidat untuk waktu yang tidak ditentukan.