a-cosmology-group/acg#316

We have recently entered the era of high resolution spectroscopy, this not only allow to detect atoms and orphan spectral lines but also molecules, including organic molecules, when present in large quantity.

As a consequence, we are for the first time detecting some organic molecules in space, some of them have no abiotic (lifeless) synthesis mechanism known (or efficient enough) Indeed a few days ago was announced the “strongest” smoking gun signature of extraterrestrial life on a giant planet (supposedly habitable through an exotic hycean (hydrogen ocean) speculated biome. JWST detected at decently high sigma detection for large amounts of dimethyl sulfide and dimethyl disulfide. https://phys.org/news/2025-04-astronomers-strongest-life-planet.html

While this is absolutely very interesting, it is not an absolute proof, for example abiotic oxygen and fossil fuels have only recently been detected on earth https://phys.org/news/2024-07-metallic-minerals-deep-ocean-floor.html

Sadly, dimethyl sulfide has tentatively been detected in a comet https://arxiv.org/abs/2410.08724 (though better measurements are needed) unless such comet material would come from an habited planet.. this gives strong evidence for an abiotic mechanism of dimethyl sulfide generation, which is currently unknown to science. It has also been detected in the ISM which rule out more the concept https://arxiv.org/abs/2501.08892 potential mechanism https://iopscience.iop.org/article/10.3847/2041-8213/ad74da

However as a reminder, the reason we have discovered zero earth clone is not because they are not abundant, but because our instruments are not sensitive enough, we will detect the first earth clones in ~2 years While Fermi’s paradox seems like a fatality, it is not necessarilly as one can decouple the abundance of life from the ability of life to explore other planets, via rydberg matter spaceship destruction or via other filters, such as the rarity of spontaneous generation of general intelligence/language, etc