Astro Blog

By RHETT ALLAIN , Wired.  Excerpt: Betelgeuse, ...red supergiant has dimmed repeatedly in the past few years, which could mean that it's ready to go full supernova quite soon—and by “soon” we mean within the next 10,000 years. ...If Betelgeuse does blow, it will be the brightest supernova ever witnessed by humans. ...A  supernova that was observed in 2015 (ASASSN-15h)  had a peak luminosity of around 2 x 10 38  watts. That's more power output than 500  billion  suns. It's crazy. Oh, you didn't see that one? Yeah, because it was in a different galaxy. Betelgeuse is in our back yard, astronomically speaking. ...to a Betelgeuse supernova... start with a luminosity of 2 x 10 38  watts, like that supernova in 2015. For the distance, I'm going to use 500 light-years. ...With that, the intensity of the light received by Earth would be 0.711 watts per square meter. ...Crunching the numbers gives me a brightness magnitude of –18.5—which ...will be by far the brightest object

By Katrina Miller , The New York Times.  Excerpt: China brought a capsule full of lunar soil from the far side of the moon down to Earth on Tuesday, achieving the latest success in an ambitious schedule to explore the moon and other parts of the solar system. The sample, retrieved by the China National Space Administration’s Chang’e-6 lander after a 53-day mission, highlights  China’s growing capabilities in space  and notches another win in a series of lunar missions that started in 2007 and have so far been executed almost without flaw....  Full article at https://www.nytimes.com/2024/06/25/science/change-6-china-earth-moon.html . 

By Dennis Overbye , The New York Times.  Excerpt: Since the James Webb Space Telescope began operating two years ago, astronomers have been using it to leapfrog one another millions of years into the past, back toward the moment they call cosmic dawn, when the first stars and galaxies were formed. Last month, an international team doing research as the JWST Advanced Deep Extragalactic Survey, or JADES, said it had identified the earliest, most distant galaxy yet found — [JADES-GS-z14-0] a banana-shaped blob of color measuring 1,600 light-years across. It was already shining with intense starlight when the universe was in its relative infancy, at only 290 million years old, the astronomers said. ...the wavelength of light from JADES-GS-z14-0 had been stretched more than 15-fold by the expansion of the universe (a redshift of 14 to use astronomical jargon), similar to the way a siren’s pitch becomes lower as it speeds away. That means light has been coming toward us for 13.5 billion year

By Dan Falk , Smithsonian Magazine.  Excerpt: The casual observer may envision the night sky as being static: When we look at Orion ...or the stars that make up the Big Dipper, our view is very similar to what our grandparents, or even  their  grandparents, would have seen.... But ...when astronomers look at the sky more closely, countless “transient” phenomena come to light ...variable stars, ...supernovas...; and thousands of objects too faint to see with the unaided eye, like asteroids, move steadily across the sky. ...The Vera C. Rubin Observatory, nearing completion ...in northern Chile, ...with a primary mirror 28 feet across and a 3.2-gigapixel camera, will sweep across the sky night after night, requiring a mere five seconds to reposition itself after each 15-second exposure. ...its large field of view—encompassing an area equivalent to 40 full moons—and its ability to move swiftly, the telescope will scan the entire visible sky every three days. ...The camera, together with th

By DANIEL CLERY , Science.  Excerpt: Living on one of the seven Earth-size planets in the TRAPPIST-1 system would be strange.... Looming ominously in the sky is an enormous red star, prone to fiery outbursts and appearing several times bigger than the Sun. Hours of the day don’t exist; each planet is tidally locked to the star so that one side is forever scorchingly hot, the other eternally frozen. Along the margin dividing the day- and nightsides—the only place with a tolerable climate—a ceaseless wind blows and the star hangs on the horizon, in perpetual sunset. A short stroll into the dark side brings your planetary companions into view. Every few days one or more passes overhead like a floating lantern, larger than the Moon. ...the quest to learn whether one of the TRAPPIST-1 planets could make a comfortable home for our imaginary observer has been an exercise in frustration. When the  seven known planets around TRAPPIST-1 were revealed in 2017 , they were ...the best place to look

By EMILY LAKDAWALLA  , Sky & Telescope.  Excerpt: Martian gullies have been the center of a debate about whether Mars ever has flowing water. Now, a comprehensive study examines the question. Lots of Mars’s hillslopes have gullies, steep ravines that grow when we’re not looking. They look so much like Earth’s own gullies, formed when water and debris carve into steep slopes, that it’s easy to think that water must be involved on Mars, too. But physics says water shouldn’t ever be liquid anywhere on the Martian surface today. Many scientists therefore think gully formation must be triggered by some kind of dry process, involving ice (either water ice or carbon dioxide ice) that  sublimates  directly from solid to gas. In a new study, published in the August 2024 issue of  Icarus , Axel Noblet (University of Western Ontario, Canada) and colleagues amass data on nearly 8,000 gullied slopes and come up with an answer to the “wet or dry” question: It’s both, and it depends. ...The corre

By Damond Benningfield , Eos/AGU.  Excerpt: The  Winchcombe meteorite  splashed into headlines on 28 February 2021, when it streaked above Gloucestershire, England, and broke apart in the atmosphere. Its largest chunk hit a driveway in the village of Winchcombe and splattered into thousands of pieces. ... Analysis of the meteorite  and video of its descent revealed that its parent meteoroid was probably 20–30 centimeters in diameter when it hit the atmosphere, with a mass of about 13 kilograms. ...The research team’s analyses revealed that the meteorite contains eight rock types, all of which show evidence of having been altered by water. ...In addition to revealing the asteroid’s history, the lab work also supported the suggestion that CM and other carbonaceous chondrites supplied young Earth with water and organic compounds....  Full article at https://eos.org/articles/a-splashy-meteorite-was-forged-in-multiple-collisions . 

By ARIELLE FROMMER , Sky & Telescope.  Excerpt: In the search for planets around other stars, astronomers often seek worlds that are most like our own. The discovery of Gliese 12b — the closest, transiting, temperate, Earth-size planet found to date — promises possibilities for understanding how terrestrial planets become habitable. Gliese 12b orbits a cool red dwarf star around 40 light-years away — practically neighborly compared to other exoplanets — with a period of 12.8 days. Its distance from its host star means that its surface might be temperate enough for life, with a temperature of 107°F (42°C). ...Gliese 12b was initially detected by NASA’s Transiting Exoplanet Survey Satellite (TESS), a mission that searches for changes in stellar brightness and records  transits  that occur when a planet passes in front of its host star. ...Red dwarf stars, or  M  stars, have small masses and radii and low luminosities, which means any planets orbiting in the “habitable zone” (the orbi