Will Solar Panels Work at Proxima Centauri?

By Brian Koberlein - October 05, 2023 11:04 AM UTC | Exoplanets
Solar panels are the perfect way to provide electricity for spacecraft operating near the Sun. Spacecraft as far out as Jupiter can still power their instruments with solar panels. But would these devices work at other stars? A new study looked at the light output of different types of stars and compared them to solar panels using the Sun. An interesting example is Proxima Centauri, which could be the first star we visit with an interstellar probe.
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Old Stars Don't Have Hot Jupiters

By Brian Koberlein - October 04, 2023 02:17 PM UTC | Exoplanets
Hot jupiters are giant planets that orbit extremely close to their stars, completing an orbit in a few days or hours. We have nothing like them in the Solar System, but astronomers think they're present in roughly 1% of star systems. But all stars? According to a new study, hot jupiters are mainly a young star thing. They looked at all the hot jupiters discovered so far, compared them against the estimated age of the stars, and found that the young stars had hot jupiters. They suggest that orbital decay pulls hot jupiters closer and close until they're inevitably consumed, which is why we don't see them around old stars.
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Astronomers Watched a Massive Star Just... Disappear. Now JWST Might Have Some Answers

By Brian Koberlein - October 03, 2023 11:39 AM UTC | Stars
In 2009, astronomers watched a bizarre mystery unfold. An enormous star, with 25 times the mass of the Sun, faded away and disappeared. Although it had been long theorized, it's believed this was a type of failed supernova, where a giant star imploded into a black hole without a bright flash. Astronomers have turned the mighty JWST on the region and found a bright infrared source. Their observations match a stellar merger instead of a single star failed supernova, but there are still more questions than answers.
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It's Confirmed. M87's Black Hole is Actually Spinning

By Brian Koberlein - October 02, 2023 12:28 PM UTC | Black Holes
The supermassive black hole at the heart of M87 was the target of the Event Horizon Telescope, revealing the area around its event horizon for the first time. Although an accretion disk surrounded the black hole, astronomers weren't sure if the black hole itself was rotating. They imaged the region with radio telescopes and discovered the remnants of polar jets, showing that the black hole's rotation axis had undergone precession over time. This precession indicates that the black hole is rotating; they're just not sure how quickly yet.
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The Milky Way's Mass is Much Lower Than We Thought

By Brian Koberlein - September 30, 2023 01:40 PM UTC | Milky Way
How massive is the Milky Way? According to a new study using data from ESA's Gaia spacecraft, less than we thought. A new estimate puts the Milky Way's mass at 200 billion times the mass of the Sun, which is 4-5 times less than previous estimates that pegged it closer to a trillion solar masses. Using detailed information about millions of stars, astronomers were able to build an extremely accurate rotation curve for the Milky Way and use that to estimate its mass. They found that the rotation of the Milky Way isn't typical for large spiral galaxies, decreasing its estimated mass.
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It's Official, Antimatter Falls Down in Gravity, Not Up

By Brian Koberlein - September 29, 2023 03:12 PM UTC | Physics
Since the discovery of antimatter decades ago, particle physicists have wondered if these particles were repulsed by gravity. Einstein predicted that despite having opposite charges to its regular matter counterparts, antimatter should still behave like matter does concerning gravity. This has been tricky to confirm experimentally since it's hard to make enough antimatter to observe its behavior. Particle physicists have finally pulled it off, using the ALPHA-g experiment at CERN, generating antihydrogen atoms and then dropping them in a 3-meter tall vertical shaft.
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Dark Matter Could Be Annihilating Inside White Dwarfs

By Brian Koberlein - September 29, 2023 01:00 PM UTC | Physics
Astronomers still don't know what dark matter is, but one of its characteristics is that it has a small "cross section," which means that it doesn't interact with regular matter or itself. However, if it's possible to trap dark matter in a region dense enough, it might interact and annihilate, releasing gamma radiation. A new paper suggests that astronomers use gamma-ray observatories to scan white dwarf stars to discover whether there's an excess of radiation coming from them. This might mean there's dark matter trapped inside, providing more clues to its nature.
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If You Could See Gravitational Waves, the Universe Would Look Like This

By Brian Koberlein - September 22, 2023 09:00 AM UTC | Physics
Our biology limits our vision. Our eyes can only perceive specific wavelengths of light. But what if we could see the Universe in gravitational waves? A new NASA simulation mapped out hundreds of collisions between dense objects, like white dwarfs, neutron stars, and black holes. These collisions happen within galaxies, sending ripples of gravitational waves across the Universe, and would allow astronomers to recreate the shape of galaxies over time. Upcoming observatories will detect tens of thousands of ultra-compact binary stars, providing even higher resolution—an entirely new way to observe the Universe.
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