S05E158 — “The Crater Makers” · Tuesday 4 August 2026. Four stories on cosmic impacts — and a new map of the X-ray sky — plus a both-hemispheres skywatch. ① A dead Falcon 9 is about to crater the Moon ● A spent SpaceX Falcon 9 upper stage (catalogued 2025-010D) is predicted to strike the Moon near Einstein Crater on 5 Aug 2026 at ~06:35 UTC — the second documented uncontrolled rocket impact on the Moon. ● The stage launched Firefly’s Blue Ghost and ispace’s Resilience landers in Jan 2025, then was stranded in a chaotic Earth orbit for ~18 months. Impact speed ~2.4 km/s (~5,400 mph); expected crater ~17–27 m across. ● Prediction by Bill Gray (Project Pluto). NASA’s LRO can image the site before and after; a ~two-dozen-author campaign is coordinating observers to chase the ejecta plume. ● Governance angle: no international framework governs cislunar debris — a growing hazard as lunar traffic increases (callback to E154’s distant-retrograde-orbit debris study). Sources: Space.com / Forbes / Reuters (Cris Tolomia) — impact preview, 31 Jul–3 Aug 2026 · Project Pluto (Bill Gray) — 2025-010D impact page · ZME Science — impact timing, 3 Aug 2026 ② Neptune’s inner moons: shrapnel of a shattered world ● JWST NIRSpec spectroscopy of Neptune’s inner moons Larissa, Galatea and Proteus (Caltech; lead author Ryleigh Davis, Mike Brown’s group) detected magnesium-rich phyllosilicates — clay minerals that require liquid water and had never been seen beyond Jupiter. ● The clays imply the material came from much larger, water-bearing worlds — evidence that Neptune’s original regular moon system was destroyed when Triton (a captured Kuiper Belt object) arrived. ● Proteus, the largest of the three, lacks the clays — possibly re-heated and reprocessed after re-forming, hiding its history. Sources: Davis et al., Science Advances, 29 July 2026 · Caltech / phys.org press coverage, 29 Jul–3 Aug 2026 · Space.com (Charles Q. Choi), 3 Aug 2026 ③ “Charbroiled within hours”: impact dust and the dinosaurs ● New modelling (Brandon Johnson et al., Purdue) argues ultrafine impact dust from Chicxulub acted as an insulating blanket, raising surface heating ~3.5× above the spherule-only estimate — enough to ignite global wildfires and kill exposed animals within hours. ● The same dust then blocked sunlight for years — so the model adds a ferocious opening act to the established “impact winter,” rather than replacing it. Sheltering underground or underwater aided survival. ● Caveat: the strongest physical wildfire evidence is so far confined to North America (per UCL’s Alfio Chiarenza, not involved in the study); a truly global fire record remains unconfirmed. Sources: Johnson, Johnson, Wakita & Robertson, JGR: Biogeosciences, 2026 · Popular Science / Space.com / ZME Science, 28 Jul–2 Aug 2026 ④ eROSITA DR2 — the X-ray sky doubles ● The eROSITA telescope (SRG mission) released its second data set (DR2) on 31 July 2026: ~1.9 million pointlike and ~64,000 extended X-ray sources from the first three all-sky scans — nearly doubling the previously released eROSITA catalogue. ● For scale: ROSAT catalogued ~130,000 sources in the 1990s and was the benchmark for 30 years. Lead author: Miriam Ramos-Ceja (MPE). ● DR2 delivers the first direct census of cataclysmic-variable binaries sufficient to explain the decades-old Galactic Ridge X-ray Emission. It coincides with SDSS DR20 (Black Hole Mapper), enabling 3D mapping of active black holes. Sources: Ramos-Ceja et al. (eROSITA-DE), arXiv:2607.27772; DR2 release · Max Planck Society press release, 29 July 2026 · phys.org, 31 Jul 2026 Skywatch — both hemispheres ● Falcon 9 impact (5 Aug, ~06:35 UTC): not naked-eye; ejecta plume a long shot for advanced amateurs in the Americas near the western limb (~2:35 a.m. EDT). Sydney: Moon below horizon — watch for LRO after-images. ● Comet 10P/Tempel 2: perihelion 2 Aug, closest to Earth 3 Aug (~0.41 AU); ~mag 8–9 near M30 in Capricornus. Best return of the century; Southern-Hemisphere-favoured; Northern viewers low on the southern horizon. Darkest window ~7–8 Aug. ● This evening: Venus threads between Regulus (Leo) and Spica (Virgo) in the west — both hemispheres, no equipment. Mercury at its best morning showing (greatest western elongation 2 Aug), low in the pre-dawn east. ● Diary — 12 Aug: total solar eclipse (Greenland/Iceland/Spain), moonless Perseid peak, six-planet alignment. Always use certified ISO 12312-2 eclipse glasses / solar filters except during totality. Become a supporter of this podcast: https://www.spreaker.com/podcast/astronomy-daily-latest-space-news--5648921/support. Sponsor Details: Ensure your online privacy by using NordVPN. To get our special listener deal and save a lot of money, visit www.astronomydaily.io/nordvpn. You'll be glad you did! Get the best secure and private email on the planet. Stop your Government, google and who knows who else spying on every email you write. Do what we did and use ProtonMail. They beleive in privacy and there are no ads in their business model...yet they still provide a free forever service. Check them out and get out special deal at www.astronomydaily.io/protonmail Become a supporter of Astronomy Daily by joining our Supporters Club. Commercial free episodes daily are only a click way... Click Here This episode includes AI-generated content.
