A Gamma Ray Burst Lasted So Long it Triggered a Satellite Twice

By Brian Koberlein - July 26, 2023 04:39 PM UTC | Extragalactic
amma-ray bursts are the most powerful explosions in the Universe, briefly outshining all the stars in their galaxy combined. They typically last for just seconds or a few minutes at the most. In 2022, an ultra-long gamma-ray burst exploded in the sky, lasting so long, with two separate blasts of radiation that it triggered the Fermi Gamma-Ray Burst Monitor twice. The blast was clocked at almost 1000 seconds, with a double blast that made some astronomers wonder if it was due to a gravitational lens.
Continue reading

Astronomers Have a New Trick to Work out the Age of Stars

By Brian Koberlein - July 25, 2023 12:11 PM UTC | Stars
Determining the age of a star is surprisingly tricky and has wide error bars. It's only inside star clusters that you get a chance to accurately measure a star's age since they all had the exact origin and age. But a new technique hopes to discover the age of stars by measuring their rotation. As stars get older, their rotation rate slows down. By plotting the rotation rates of stars in clusters against their known ages, they can apply it to individual stars which aren't in clusters.
Continue reading

Venus Needed Asteroid Impacts to Get its Volcanoes Going

By Brian Koberlein - July 24, 2023 01:11 PM UTC | Planetary Science
Unlike Earth, Venus lacks the plate tectonics that give rise to volcanoes. But the surface of Venus looks far younger than other worlds, like Mars or the Moon, which means it does have volcanic activity that regularly resurfaces the planet. Because Venus is closer to the Sun, it came farther out in the Solar System and hit the planet at higher velocities. A new study suggests that early catastrophic asteroid impacts melted its mantle, leading to its flavor of volcanism.
Continue reading

One Side of This White Dwarf is Covered in Hydrogen While the Other Side is Helium.

By Brian Koberlein - July 21, 2023 01:15 PM UTC | Stars
Here's a new one. Astronomers have found a white dwarf star - the dead remnant from a main sequence star like the Sun - with one hemisphere composed of hydrogen while the other is covered in helium. The star was discovered with the Zwicky Transient Facility, revealing that it rotates every 15 minutes. Spectroscopic data unveiled its two-sided nature. What?! Also. How?! Some white dwarfs transition from hydrogen- to helium-dominated surfaces, and astronomers might have caught it in the act.
Continue reading

Thin Flat Lenses Could Unleash a Revolution in Space Telescopes

By Brian Koberlein - July 20, 2023 01:08 PM UTC | Telescopes
Space telescopes use traditional polished mirrors like ground telescopes, which are heavy, unwieldy, and expensive to build. A new type of flexible telescope lens could be lighter and larger, creating space telescopes that could collect 100 times more light than JWST. Instead of a single large, delicate telescope, the Nautilus Space Observatory would consist of a fleet of lighter, cheaper, identical spacecraft working together to produce images. They'd use thin diffractive lenses, which have been improved to the point that they can produce near-perfect image quality.
Continue reading

Did That Message Come From Earth or Space? Now SETI Researchers can be Sure

By Brian Koberlein - July 19, 2023 02:45 PM UTC | Astrobiology
When SETI researchers discover an intriguing radio signal, their first instinct is to ask, "Is the signal coming from Earth?" So many alien messages turned out to be Earth signals reflecting off objects in space, like satellites. Scientists have developed a new technique to vet these signals and confirm whether they came from outer space, even with a single message. When a signal passes through the interstellar medium, it should be affected by free electrons from cold plasma, and it's possible to separate the genuine interstellar message from one that emanated close to Earth.
Continue reading

Your Oven Gets Hotter Than This Star

By Brian Koberlein - July 18, 2023 12:36 PM UTC | Stars
Astronomers have an ultracool star that only has a surface temperature of 425 degrees centigrade, cooler than the cleaning cycle of a typical oven. For comparison, the Sun has a surface temperature of about 5600 C. This isn't the coldest star ever seen, but it's the coldest that was discovered using radio astronomy. This class of ultracool brown dwarfs is challenging to find because they don't have the kind of dynamics that produce magnetic fields and generate radio waves. Stars are active in the radio spectrum because of their magnetic fields, so it's puzzling to find these brown dwarves so inactive.
Continue reading

Liquid Water on Rocky Planets Could be 100 Times More Likely

By Brian Koberlein - July 16, 2023 02:36 PM UTC | Exoplanets
Astronomers previously believed that you needed a special environment for a rocky planet to have liquid oceans on its surface, with just the right temperature and surface pressure. But a new study suggests that the radioactivity from rocks could melt water. Even if the surface is frozen, there could be oceans of water beneath the surface. Researchers suggest that there could be an average of one planet per star with these conditions in the Milky Way - 100 times more likely than previous estimates.
Continue reading

We've Got to Go Back to Enceladus. Here's a Mission That Could Get the Science

By Brian Koberlein - July 14, 2023 11:21 AM UTC | Planetary Science
Saturn's moon Enceladus is one of the most promising places to look for life in the Solar System. It has an ocean of liquid water venting into space, and evidence from Cassini suggested that it's filled with organic molecules and nutrients for bacteria. A new mission that could continue the search, the Astrobiology eXploration at Enceladus (AXE), has been proposed. This would be a New Frontiers-class mission with a modest budget and a suite of instruments specifically chosen to maximize the science at Enceladus.
Continue reading

Celebrate a Year of JWST With This Ludicrous Image of Rho Ophiuchi

By Brian Koberlein - July 13, 2023 12:00 PM UTC | Extragalactic
It's been a year since JWST began its operations, so the people behind the telescope released a stunning new image to celebrate. The Rho Ophiuchi complex is already a famous target for astrophotographers because of its many-colored splendor. Under JWST's infrared gaze reveals the closest star-forming region to Earth in all its glory. Jets are blasting out of newly forming stars, impacting the surrounding interstellar gas and lighting up molecular hydrogen. Some of the stars even have the shadows of circumstellar disks.
Continue reading

Titanium Clouds Make This Exoplanet Shine Like a Mirror

By Brian Koberlein - July 12, 2023 12:56 PM UTC | Exoplanets
ESA's Cheops mission has been studying an ultra-hot exoplanet around a nearby star and discovered its metallic clouds reflect about 80% of the light shining on it from its host star. The planet is about the size of Neptune, and its high-temperature clouds are filled with silicate mixed with metals like titanium. The planet takes only 19 hours to orbit its star, and astronomers are puzzled why it hasn't had its atmosphere blown away, leaving only bare rock behind. The metal clouds might actually be the solution, reflecting the heat away and preventing the atmospheric stripping.
Continue reading