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    In the (convection) zone: Astronomers eavesdrop on stars’ innate “twinkle” / ArsTechnica · Tuesday, 22 August - 20:46 · 1 minute

Visualization of "Twinkle, Twinkle, Little Star" played through three sizes of massive stars. Credit: Northwestern University.

Science 101 tells us that the twinkling appearance of stars from our vantage point on Earth is due to atmospheric effects: winds and varying temperatures and densities in the air bend and distort the light. But stars have another sort of "twinkle" produced by how gases ripple in waves across their surface, an effect that could provide astronomers with a handy means of exploring the interior of massive stars to learn more about how they form and evolve. But the effect is much too small to be readily detected by telescopes.

So scientists have now developed the first 3D simulations of that innate twinkle, according to a recent paper published in the journal Nature Astronomy. As a bonus, the researchers converted the data from those rippling waves of gas into an audible sound, so now we can all take a moment to listen to "Twinkle, Twinkle, Little Star" (see video above) and Gustav Holst's "Jupiter" (see video below) in the "language" of the stars.

“Motions in the cores of stars launch waves like those on the ocean,” said co-author Evan Anders of Northwestern University. “When the waves arrive at the star’s surface, they make it twinkle in a way that astronomers may be able to observe. For the first time, we have developed computer models which allow us to determine how much a star should twinkle as a result of these waves. This work allows future space telescopes to probe the central regions where stars forge the elements we depend upon to live and breathe.”

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    An exoplanet is getting vaporized but is trying to hide it / ArsTechnica · Tuesday, 15 August - 17:06

Image of a cloud of blue gas and a planet in front of a small, red star.

Enlarge / Artist's conception of the atmosphere being blasted off an exoplanet. (credit: NASA, ESA, and Joseph Olmsted (STScI) )

Some planets cannot hold on to their atmospheres. It's thought that most of whatever atmosphere Mars may have had was annihilated by the solar wind billions of years ago, even as Earth and Venus held on to theirs. But there are planets that orbit so close to their star that atmospheric loss is inevitable. With at least one of them, we’ve learned that it is also unpredictable.

Exoplanet Au Mic b is that planet. It orbits the young, hot, and temperamental red dwarf star Au Microscopii (Au Mic), which is only 23 million years old—nothing compared to our 4-billion-year-old sun. NASA’s Hubble Space Telescope caught this scorched world losing a portion of its atmosphere.

When a team of scientists from the NASA Goddard Space Flight Center, Dartmouth College, the University of California at Santa Cruz, and other institutions analyzed the Hubble observations, they were confused by the planet’s erratic behavior. There would be evidence of atmospheric loss in some of the data, then suddenly none at all. It was unpredictable.

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    Rogue planets may be more numerous than stars in our galaxy / ArsTechnica · Tuesday, 8 August - 14:35

Image of a planet against a dark background.

Enlarge / An artist's conception of an ice-encrusted rogue planet. (credit: NASA’s Goddard Space Flight Center )

Planets that go rogue orbit no star. They wander the vacuum of space alone, having been kicked out of their star systems by gravitational interactions with other planets and stars. Nobody really knows how many rogue planets could be out there, but that may change in a few years.

Researchers from NASA’s Goddard Space Flight Center and Osaka University in Japan have used the phenomenon of gravitational microlensing to estimate the number of rogue planets that could be revealed in the heart of the Milky Way. They analyzed data from the Microlensing Observations in Astrophysics (MOA) survey that searched for gravitational microlensing events from 2006 to 2014 to figure out how many more of these events we could expect to find with NASA’s upcoming Nancy Grace Roman Space Telescope.

There are currently only 70 known rogue planets, but there could be hundreds more out there. The researchers now suggest that Roman could discover at least 400 Earth-mass rogues meandering through our galaxy.

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    Communal stargazing using your phone: The Unistellar eQuinox 2, reviewed / ArsTechnica · Saturday, 29 July - 10:30 · 1 minute

The eQuinox 2 is ready for sundown in central Illinois. No eyepiece here, so have your smartphone handy if you want to stargaze.

Enlarge / The eQuinox 2 is ready for sundown in central Illinois. No eyepiece here, so have your smartphone handy if you want to stargaze. (credit: Eric Bangeman/Ars Technica)

When we reviewed the Unistellar eVscope a couple of years ago, we came away impressed. It offered a communal stargazing experience that takes our ubiquitous smartphones and turns them into a way to view the heavens. Unistellar's newest offering is the eQuinox 2, a lower-cost alternative to eVscope 2, taking all of the features from its original telescope, improving the technology, and dropping the price to $2,499.

Unistellar's smart telescopes are designed to make astronomy more accessible by automating skywatching and using digital sensors to "collect" light from faraway objects, making light pollution a small nuisance instead of a deal-breaker.

At a glance, the biggest difference between the eQuinox 2 and its predecessor is the former's lack of an eyepiece. Unistellar got rid of the eyepiece, which isn't much of a loss. Instead of taking turns peering through the eyepiece, up to 10 people can stargaze simultaneously with the Unistellar app. Connect to the telescope's built-in Wi-Fi network, launch the app, and you're ready to scan the skies. One person controls the telescope and everyone else can watch. The operator can give control of the telescope to anyone else easily.

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    Rover sampling finds organic molecules in water-altered rocks / ArsTechnica · Wednesday, 12 July - 22:18 · 1 minute

Greyscale image of a large fan of material spread out across a crater floor.

Enlarge / Jezero crater shows clear signs of water-formed deposits, so it's not a surprise to find water-altered material there. (credit: NASA/MSSS/USGS )

Organic chemicals, primarily composed of carbon and hydrogen, underly all of life. They're also widespread in the Universe, so they can't be taken as a clear signature of the presence of life. That creates an annoying situation regarding the search for evidence of life on Mars, which clearly has some organic chemicals despite the harsh environment.

But we don't know whether these are the right kinds of molecules to be indications of life. For the moment, we also lack the ability to tear apart Martian rocks, isolate the molecules, and figure out exactly what they are. In the meantime, our best option is to get some rough information on them and figure out the context of where they're found on Mars. And a big step has been made in that direction with the publication of results from imaging done by the Perseverance rover.


The instrument that's key to the new work has a name that pretty much tells you it was designed to handle this specific question: Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals (SHERLOC). SHERLOC comes with a deep-UV laser to excite molecules into fluorescing, and the wavelengths they fluoresce at can tell us something about the molecules present. It's also got the hardware to do Raman spectroscopy simultaneously.

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    The Webb telescope just offered a revelatory view of humanity’s distant past / ArsTechnica · Wednesday, 12 July - 13:59

The first-anniversary image from NASA’s James Webb Space Telescope displays star birth like it’s never been seen before.

Enlarge / The first-anniversary image from NASA’s James Webb Space Telescope displays star birth like it’s never been seen before. (credit: NASA, ESA, CSA, STScI, Klaus Pontoppidan (STScI))

To commemorate the first year of scientific operations by the James Webb Space Telescope, NASA has released a stunning new image of a stellar nursery.

The photo is gorgeous. It could easily hang in a museum, as if it were a large canvas painting produced by a collaboration of impressionistic and modern artists. But it is very real, showcasing the process of stars being born a mere 390 light years from Earth. This is the Rho Ophiuchi cloud complex, the closest star-forming region to Earth.

Given the nursery's proximity and Webb's unparalleled scientific instruments, we have never had this kind of crystal-clear view of these processes before. The detail revealed in this image of about 50 stars is truly remarkable, a distillation of all that Webb has delivered over the last 12 months and all that it promises to do over the next 10 or 20 years.

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    “Lensed” supernova could shed light on fundamental forces shaping Universe / ArsTechnica · Monday, 12 June - 16:27 · 1 minute

gravitational lensing image of supernova

Enlarge / Gravitational lensing has revealed a previously unknown supernova explosion more than 4 billion light-years away. (credit: Joel Johansson, Stockholm University)

Astronomers have detected a previously unknown supernova explosion more than 4 billion light-years away using a rare phenomenon called "gravitational lensing," which serves as a kind of cosmic magnifying glass. They described their discovery and its potential implications in a new paper published in the journal Nature Astronomy. Co-author Ariel Goobar, director of the Oskar Klein Center at Stockholm University, described the find as "a significant step forward in our quest to understand the fundamental forces shaping our universe."

Gravitational lensing is a direct consequence of the general theory of relativity: mass bends and warps spacetime, and light must follow that curvature. The phenomenon can form rare effects like an " Einstein ring " or an " Einstein cross ." Essentially, the distortion in space-time caused by a massive object (like a galaxy) acts as a lens to magnify an object in the background. Since these aren't perfect optical-quality lenses, there are often some distortions and unevenness. This causes the light from the background object to take different paths to Earth, and thus a single object can appear in several different locations distributed around the lens. At cosmological scales, those paths can also require light to travel very different distances to get to Earth.

Gravitational lensing helps astronomers spot celestial objects that might otherwise be too faint or far away to see, like a distant supernova, which can lead to other interesting questions. For example, last year , astronomers analyzed a Hubble image from 2010, where the image happened to also capture a supernova. Because of gravitational lensing, the single event showed up at three different locations within Hubble's field of view. Thanks to the quirks of how this lensing works, and because light travels at a finite speed, all three of the locations captured different times after the star's explosion, allowing researchers to piece together the time course following the supernova, even though it had been observed over a decade earlier.

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    A telescope happened to be pointing at the brightest supernova yet observed / ArsTechnica · Friday, 9 June - 00:04 · 1 minute

Image of a narrow beam of material extending from a complex spherical cloud of material.

Enlarge / Artist's conception of a gamma-ray burst. (credit: NASA )

Supernovae are some of the most energetic events in the Universe. And a subset of those involves gamma-ray bursts, where a lot of the energy released comes from extremely high-energy photons. We think we know why that happens in general terms—the black hole left behind the explosion expels jets of material at nearly the speed of light. But the details of how and where these jets produce photons are not at all close to being fully worked out.

Unfortunately, these events happen very quickly and very far away, so it's not easy to get detailed observations of them. However, a recent gamma-ray burst that's been called the BOAT (brightest of all time) may be providing us with new information on the events within a few days of a supernova's explosion. A new paper describes data from a telescope that happened to be both pointing in the right direction and sensitive to the extremely high-energy radiation produced by the event.

I need a shower

The "telescope" mentioned is the Large High Altitude Air Shower Observatory (LHAASO). Based nearly three miles (4,400 meters) above sea level, the observatory is a complex of instruments that aren't a telescope in the traditional sense. Instead, they're meant to capture air showers—the complex cascade of debris and photons that are produced when high-energy particles from outer space slam into the atmosphere.

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