GJ 3090 b orbits its red dwarf backwards and leaves theorists without a giant companion to blame
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Astronomy & Astrophysics and arXiv report GJ 3090 b on a retrograde orbit (ψ ≈ 136°) around its M dwarf — the first such case for a red-dwarf host — with no detected massive companion to explain the tilt.
Mercury may have shrunk by up to twenty-three kilometres once rough terrain stops hiding the wrinkles
Nature’s research highlight of 17 September 2026 flagged a Geophysical Research Letters paper by Gaku Nishiyama and colleagues: Mercury’s diameter may have shrunk by around 23 kilometres since formation — more than many earlier tallies — because impact…