Helium escaping from the atmosphere of a nearby rocky exoplanet orbiting in a habitable zone

September 3, 2026| Source: Science

Observations of highly irradiated gas giant exoplanets have shown helium escaping from their atmospheres. There is limited evidence for atmospheres on rocky exoplanets, perhaps because they have already escaped. We report near-infrared spectroscopic observations of LHS 1140b, a rocky exoplanet that orbits in the habitable zone of a nearby low-mass star. The transit spectra show absorption by helium escaping from the planet’s atmosphere. Helium absorption is detected in 2024 but not in 2025, indicating time-variable atmospheric escape. We interpret these results as indicating an upper atmosphere dominated by helium and depleted in hydrogen, with other volatile species trapped at lower altitudes, which is consistent with atmospheric fractionation models. No helium absorption is detected for LHS 1140c, a smaller and more strongly irradiated exoplanet in the same system.

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Historical trends show more declining than increasing species among European pollinators.

Anthropogenic global change presents a growing threat to insect pollinators. Yet, long-term, continental-scale assessments of their population trends remain limited. Here, we leveraged a curated database of over four million occurrence records, covering 88% of extant bee and hoverfly species in Europe, to assess persistence, richness, and occupancy trends over the past century. Species persistence at the European level was relatively high, with modern records available for 87% of bee and 89% of

Physical/TechNovember 3, 2026

The ABCD hypothesis.

If [Formula: see text] and [Formula: see text] are cardinals, then the cardinal exponentiation [Formula: see text] is the set of all functions from [Formula: see text] into [Formula: see text]. The ABCD hypothesis is the statement that for all infinite cardinals [Formula: see text] and [Formula: see text], [Formula: see text] if and only if [Formula: see text] and [Formula: see text]. The Axiom of Determinacy, AD, states that every two-player infinite game on [Formula: see text] has a winning st

Physical/TechOctober 29, 2026

The delocalized nature of chemical bonding at a catalytic metal surface.

Adsorbate bonding at metal surfaces requires hybridization of localized molecular orbitals with delocalized electronic bands of the metal; hence, the electronic wave function involved in bonding may extend far beyond the adsorption site. We revealed the consequence of this delocalization by determining the distance over which structural variations of the metal surface influence the molecule-metal bond strength. Velocity-resolved kinetics provided adsorption energies for three molecules bound at

Physical/TechOctober 29, 2026

Chiral altermagnon in MnTe.

Altermagnetism has been recognized as a magnetic phase that bridges the properties of ferro- and antiferromagnetism. The momentum-dependent spin splitting observed in these materials reflects their distinctive symmetry characteristics, which also establish the conditions for chiral magnons to emerge. Here we provide direct experimental evidence for a chiral magnon in the altermagnetic candidate manganese telluride (MnTe) revealed by circular-dichroism resonant inelastic x-ray scattering. This mo

Physical/TechOctober 27, 2026

Extensive glacier loss in the coterminous United States.

Glaciers populate the mountain ranges of the western conterminous United States and despite their importance to alpine hydrology, their area and volume change have never been comprehensively evaluated. Our study shows that since the mid-twentieth century about one-quarter of the glaciers have disappeared and the overall area and volume are reduced by one-third. The pattern of glacier shrinkage suggests most glaciers in the conterminous United States are largely maintained by local topographic in