Nature Astronomy, Published online: 28 December 2023; doi:10.1038/s41550-023-02134-2 If advanced technological extraterrestrial lifeforms are out there, where are they? Thus goes the Fermi paradox. This Perspective reviews various solutions and proposes that they are either not there or are deliberately

Nature Astronomy, Published online: 28 December 2023; doi:10.1038/s41550-023-02159-7 The search for life elsewhere involves variables across multiple scales in time and space, often nested hierarchically. We suggest that the emergence of artificial intelligence learning systems offers critically important ways to

Nature Astronomy, Published online: 28 December 2023; doi:10.1038/s41550-023-02173-9 The testing of a direct-ascent anti-satellite weapon on 15 November 2021 has prompted renewed efforts in space arms control. A multilateral treaty banning all destructive anti-satellite weapon tests is urgently needed. —————

Nature Astronomy, Published online: 28 December 2023; doi:10.1038/s41550-023-02112-8 On Earth, technological advances required open-air combustion, which needs an oxygen partial pressure of about 18%. This threshold can help guide searches for detectable technospheres on other planets. ————— Free Secure Email

Nature Astronomy, Published online: 28 December 2023; doi:10.1038/s41550-023-02158-8 The habitability of a planet is defined at a fixed time. A bigger challenge is to understand how that habitability is sustained over geological timescales, and how the underlying processes compare across

Nature Astronomy, Published online: 28 December 2023; doi:10.1038/s41550-023-02157-9 A low atmospheric carbon abundance can be a ‘habiosignature’ and indicate the presence of substantial surficial liquid water, tectonic activity and/or a biomass in temperate rocky exoplanets. It can potentially be detected