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The National
3 days ago
- General
- The National
Earliest galaxies ever seen reveal clues to universe's first moments
Astronomers have confirmed the discovery of the two most distant galaxies observed, giving them a glimpse of what the universe looked like only 300 million years after the Big Bang. Named JADES-GS-z14-0 and JADES-GS-z14-1, the galaxies were identified by the James Webb Space Telescope (JWST) as part of the JWST Advanced Deep Extragalactic Survey (JADES). The findings, published in the Nature science journal on Wednesday, challenges existing theories on how quickly galaxies could form in the early cosmos. 'These galaxies join a small but growing population of galaxies from the first half billion years of cosmic history where we can really probe the stellar populations and the distinctive patterns of chemical elements within them,' said Dr Francesco D'Eugenio of the Kavli Institute for Cosmology at the University of Cambridge, one of the teams behind the discovery. The brighter of the two, JADES-GS-z14-0, measures an impressive 1,600 light-years in diameter and appears to be brimming with young stars. The discovery offers scientists a rare opportunity to study conditions of when the universe was first forming. The galaxies can be seen as they were when the universe was less than 2 per cent of its current age. This was possible because of instruments on the telescope that helped researchers study the phenomenon where light stretches into longer wavelengths as it travels through space. 'We could have detected this galaxy even if it were 10 times fainter, which means that we could see other examples yet earlier in the universe, probably into the first 200 million years,' says Brant Robertson, professor of astronomy and astrophysics at the University of California-Santa Cruz. The findings could also lead researchers to rethink how fast stars and other matter came together in the first few hundred million years after the Big Bang. JWST's ability to observe infrared light helped the researchers carry out the discovery, a capability that was not possible by its predecessor the Hubble Space Telescope. The telescope, which was launched on Christmas day in 2021, has already rewritten much of what scientists believed about the early universe. Among its most talked-about findings is the detection of carbon dioxide in the atmosphere of a planet outside the Solar System, a major step in the search for potentially habitable worlds. It has also provided never-before-seen details of star formation, including the stunning image of the Pillars of Creation, towering clouds of gas and dust located about 6,500 light-years from Earth, revealing intricate new structures invisible to previous telescopes. But just as the JWST is reaching new milestones, its future and other major science missions, are at risk because of the White House's proposed budget for 2026 that includes significant cuts to Nasa's science division. These cuts could affect future telescope missions, Earth science programmes and planetary exploration efforts. While JWST is already built and operational, budget constraints could limit the resources needed to support its observations or delay follow-up missions that would expand on its findings. Stunning images captured by the James Webb Space Telescope – in pictures
Yahoo
23-04-2025
- Science
- Yahoo
This Melting Planet Laid a Trail of Destruction Over 5 Million Miles Long
Astronomers have discovered one of the least habitable planets ever. This tiny world is being melted by its host star, leaving a comet-like tail that stretches millions of kilometers behind it. While we're often preoccupied with planets that might be comfy enough for liquid water to pool on the surface, the hellish landscape of BD+05 4868 Ab hosts liquid rock. These magma oceans are boiling right off the surface into space, condensing into a rocky tail. "The extent of the tail is gargantuan, stretching up to 9 million kilometers [5.6 million miles] long, or roughly half of the planet's entire orbit," says Marc Hon, astrophysicist at MIT's Kavli Institute. The unfortunate planet lies about 140 light-years away, orbiting its host star every 30.5 hours. That brings it about 20 times closer to the star than Mercury orbits the Sun – and cuddling up that close could prove to be a lethal mistake. BD+05 4868 Ab may have started out with more than double its current mass, which seems to be less than half that of Mercury, and it's getting smaller all the time. The researchers estimate that it ejects a Mount Everest's-worth of material into space with every orbit, and at that rate it will completely dissolve within 1 or 2 million years. "This is a very tiny object, with very weak gravity, so it easily loses a lot of mass, which then further weakens its gravity, so it loses even more mass," says Avi Shporer, astronomer on the Transiting Exoplanet Survey Satellite (TESS) mission. "It's a runaway process, and it's only getting worse and worse for the planet." It's only the fourth melting Mercury exoplanet discovered so far, but it has the poorest prognosis. One orbiting KIC 12557548, for example, has been given about 200 million years to live. But BD+05 4868 Ab's extensive tail is a symptom of a much faster disintegration. Other tailed exoplanets have been discovered before, but they're usually gas giants with plenty of material to spare. HAT-P-32b, for instance, is leaking helium into two tails that span more than 53 times the planet's radius. It will probably take another 40 billion years before it evaporates completely. The hot Jupiter WASP-69b is also losing its atmosphere to a tail, although it's only shrinking by one Earth mass every billion years. It'll likely face other, more pressing apocalypses, like its star blowing up, long before it needs to worry about running out of air. But back to BD+05 4868 Ab. This extraordinary exoplanet was discovered in an ordinary way, using the transit method. This involves watching a star for periodic dips in brightness, caused by a planet passing between it and the telescope viewing it. But in this case, the astronomers didn't just see a brief and regular dimming. It took much longer than expected for the brightness to return to normal after each transit. Weirder still, the amount of light filtering through during each orbit varied. That suggested that a fuzzy, inconsistent structure was trailing behind the transiting object. "The shape of the transit is typical of a comet with a long tail," says Hon. "Except that it's unlikely that this tail contains volatile gases and ice as expected from a real comet – these would not survive long at such close proximity to the host star. Mineral grains evaporated from the planetary surface, however, can linger long enough to present such a distinctive tail." Intriguingly, there's also a much smaller 'leading' tail that stretches out in front of the planet. The team says this could be especially useful to help us understand the dust tail's dynamics and test formation theories. It won't top anyone's list of holiday destinations, but BD+05 4868 Ab may still have something to teach us about more hospitable worlds. After all, it's not often that a planet blasts its innards outwards for us to analyze. JWST could perform this autopsy, studying the spectrum of the star's light as it's absorbed by the dust to reveal what the doomed planet is made of. "This will be a unique opportunity to directly measure the interior composition of a rocky planet, which may tell us a lot about the diversity and potential habitability of terrestrial planets outside our Solar System," says Hon. The research was published in The Astrophysical Journal Letters. Red Planet's Core May Explain Strange Mystery of Ancient Magnetic Field Unusual Gas on Alien World Sparks Hope of Life, And Healthy Skepticism NASA Reveals Stunning Closeup of Bizarre-Looking Asteroid
