Jwst

Every planet, ours included, assembled inside a flat disk of gas and dust that has since vanished. That disk is the raw material and the deadline at once: it survives only a few million years around a young star before the gas is gone, and any world that wants a thick hydrogen-helium atmosphere has to grab it before the tank runs dry. A new study led by Naman Bajaj at the University of Arizona used JWST to watch that gas actually leaving, mapping the jets and winds carrying it off in 72 young disks and showing how the escape route changes as a disk ages. The paper, “JWST/MIRI Reveals the Evolution from Molecular to Atomic Disk Winds”, is one of the largest JWST disk-wind surveys to date. ...

When you weigh a galaxy, you’re really weighing its light. Point a telescope at an elliptical galaxy a few billion light-years away and you record a smear of photons, and most of that light comes from a small number of bright, heavy stars. The faint red dwarfs, the ones that make up the overwhelming majority of any galaxy’s star count, are individually invisible at that distance. You never see them one by one. You infer how many there are, and you do that by assuming a galaxy far away is built from the same mix of stars as the ones nearby. ...

For almost a decade, the most closely watched rocky planet in the exoplanet catalogue has been LHS 1140 b: a super-Earth in the habitable zone of a quiet red dwarf about 48 light-years away, in the constellation Cetus. The open question was never whether it exists. We’ve known that since 2017. The question was whether a small planet sitting that close to a red dwarf could hold onto an atmosphere at all. A paper published in Science on July 16 gives the strongest answer yet, and it comes from an unexpected direction: the planet is losing gas. A Harvard-led team caught helium streaming off the top of its atmosphere. That leak, counterintuitively, is the best evidence we have that there’s an atmosphere down there to leak from. ...

I’ve now watched three objects from other star systems pass through ours, and only one of them said anything worth hearing. The first, 1I/ʻOumuamua in 2017, was gone almost before we understood what it was: a fast, tumbling sliver that never grew a tail and left us arguing about its shape. The second, 2I/Borisov in 2019, was a proper comet with a coma and a tail, alien in origin, but the kind of object we already know how to study. The third is 3I/ATLAS, and it did what the other two wouldn’t. It stayed in front of the James Webb Space Telescope long enough for Webb to read its chemistry line by line, and the readout points to a comet that froze into existence before the Sun did. ...

Since 2022, the James Webb Space Telescope has been turning up compact red objects in the deep universe that nobody predicted. More than 300 of these “little red dots” have been catalogued so far, all crammed into a narrow epoch between about 600 million and 1.6 billion years after the Big Bang. For four years, they’ve driven a sharp debate: are they impossibly massive galaxies, overgrown black holes, or something we haven’t modelled yet? A paper published on June 10 in The Astrophysical Journal by Vasily Kokorev and colleagues at the University of Texas at Austin delivers the strongest answer so far. The object they studied, GLIMPSE-17775, is a supermassive black hole cocooned in dense, hot gas — and the data suggest most little red dots are, too. ...

TOI-199b sits about 330 light-years from Earth, orbits a Sun-like star every 105 days, and holds an equilibrium temperature of roughly 352 K (79°C). That’s warm by terrestrial standards but downright mild for an exoplanet, where “hot Jupiter” atmospheres regularly top 1,500 K. A team led by Aaron Bello-Arufe at Penn State pointed JWST at a single transit of this world and pulled methane out of its atmosphere, making TOI-199b the first temperate giant exoplanet whose atmospheric composition has been directly measured. ...

When you look at galaxies through a telescope — scattered across the field like grains on dark cloth — it’s tempting to think they’re placed at random. They aren’t. Galaxies live on a structure so vast that the only metaphor that survives at scale is a web: long filaments of matter, hundreds of millions of light-years across, connecting dense knots of galaxy clusters and skirting nearly empty voids. This month, the largest survey JWST has carried out gave us the clearest map of that web to date, tracing it back to a time when the universe was barely a billion years old. ...