The interstellar objects we met along the way\u00a0<\/p>\n
Raymond, Sean et al. \u201cCapture of interstellar objects during stellar encounters.\u201d Astronomy & Astrophysics.<\/a><\/p>\n Over the past decade, three interstellar objects have been spotted streaking through our solar system. It\u2019s likely that dozens more of these interlopers will be discovered in the coming years. These objects travel so fast that they can escape the gravitational clutches of the Sun, which is why they are only visible for weeks before hurtling back out to speed-run the galaxy.<\/p>\n But while some interstellar objects (ISOs) leave in a hurry, others may be here to stay, lurking in the outermost reaches of the solar system, known as the Oort cloud, reports a new study.\u00a0<\/p>\n Over the course of its 4.6-billion year lifespan, the Sun has wandered close enough to other stars to collect thousands of non-native objects from the fringes of those passing systems. It may have also sent off many of its homegrown objects to join alien star systems during these encounters, like some kind of stellar gift exchange.<\/p>\n \u201cThe Solar System has long been suspected to contain captured, non-native material,\u201d said researchers led by Sean Raymond of the Bordeaux Astrophysics Laboratory. \u201cThe recent ISO discoveries have now confirmed directly that extraterrestrial material regularly passes through the Solar System.\u201d\u00a0\u00a0<\/p>\n Drawing on these discoveries, Raymond and his colleagues ran models to predict how many ISOs might be exchanged between stars during close encounters, called stellar flybys. The Sun is estimated to have had at least one or two of these meetups during its life so far, which could be \u201cresponsible for a large fraction of the captured ISOs currently residing in the Solar System.\u201d\u00a0<\/p>\n \u201cGiven that flybys are unavoidable in the Galactic field, most stars should host sparse Oort clouds populated with ISOs captured during stellar flybys,\u201d the team said.\u00a0<\/p>\n The Oort cloud \u2014 composed of frozen comet-like objects \u2014 extends for about three light years away from the Sun, so it\u2019s not currently possible to send a spacecraft to go out to sift for ISOs in these distant wilds. Still, it\u2019s neat to know there are so many interstellar hitchhikers riding in the Sun\u2019s backseat.<\/p>\n Ancient magic Moon beads<\/p>\n Han, Ziyan et al. \u201cLunar transient atmosphere recorded in Chang’e 6 impact glass beads.\u201d Earth and Planetary Science Letters.<\/a><\/p>\n A memory of an ancient ephemeral sky on the Moon may be locked inside glass beads scattered across the lunar surface, according to a new study.\u00a0<\/p>\n The Moon is airless, but there\u2019s evidence that it was surrounded by a transient atmosphere billions of years ago, which was fed by volcanic eruptions in its early history. Rocks crashing into the surface may have also vaporized material and created brief, gassy skies over time.<\/p>\n Scientists have now examined glass beads that were scooped up from the far side of the Moon by China\u2019s Chang\u2019e 6 sample-return mission, and delivered back to Earth in the summer of 2024 (that\u2019s so Brat). The lunar glass, which was forged by rocks crashing into the surface, captured the chemical signatures of the vapor plume created by those impacts, capturing a whiff of a long-lost transient atmosphere.<\/p>\n \u201cChang\u2019e 6 (CE6) mission has returned the first lunar samples from the farside of the Moon,\u201d said researchers led by Ziyan Han of Nanjing University. \u201cThe returned CE6 lunar regolith contains impact glass beads that could have recorded impact-induced vaporization on the Moon’s farside and may serve as barometers, providing critical constraints on the global distribution of the Moon’s transient atmosphere.\u201d<\/p>\n The team noted that these fleeting impact-induced atmospheres might exist on other airless bodies in the solar system, and beyond it. For this reason, the researchers warned that atmospheres detected around exoplanets \u201cmay not always solely represent stable, long-lived atmospheres\u201d which could \u201ccomplicate the interpretation of atmospheric data as evidence of long-term planetary habitability on the rocky exoplanets.\u201d<\/p>\n There you have it\u2014just some ancient glass beads that contain the breath of past lunar skies. Carry on.<\/p>\n The real cost of cheaper gas<\/p>\nConcept art showing the scale and spherical shape of the Oort Cloud. Image: NASA<\/p>\n
The scoop left by Chang\u2019e-6 sample collection on the Moon, which included the glass beads. Image: Chunlai Li, Hao Hu, Meng-Fei Yang\u00a0<\/p>\n