Do The Gaps in Protoplanetary Disks Really Indicate Newly Forming Planets?

By Brian Koberlein - September 12, 2023 12:45 PM UTC | Exoplanets
Modern instruments like ALMA have revealed newly forming stars surrounded by accretion disks. These images are so sensitive you can even see the gaps in the disk where new planets form, right? Maybe not. According to a new paper, systems with many newly forming planets are inherently unstable, so they can't all indicate new worlds. Some gaps and rings around the stars might just indicate collections of pebbles that can never accrete into actual planets. The challenge will be to figure out which is which.
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JWST Might Have Imaged a Hycean World for the First Time, With a Hydrogen-Rich Atmosphere and a Deep Planet-Wide Water Ocean

By Brian Koberlein - September 11, 2023 01:08 PM UTC | Exoplanets
Astronomers have directed JWST to examine the atmosphere of an exoplanet called K2-18 b, which orbits a cool dwarf star about 120 light-years from Earth. The planet is 8.6 times as massive as Earth, and the observations have revealed methane and carbon dioxide in its atmosphere. This opens up the intriguing possibility that this exoplanet is an example of a theorized "hycean world," a planet with a hydrogen-rich atmosphere and a water ocean covering its surface that extends deeper than anything we have on Earth.
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The Closest Black Holes to Earth are Probably Hidden in This Nearby Star Cluster

By Brian Koberlein - September 10, 2023 10:41 AM UTC | Black Holes
The Hyades cluster is the closest open star cluster to Earth, located at a distance of about 150 light-years. Although black holes haven't been directly seen in the cluster, it's an excellent place to search for them because the largest stars would have detonated as supernovae and collapsed in neutron stars and black holes. Astronomers have simulated the motions of stars in the cluster with black holes lurking around and then compared them to the motions of the actual stars. They only matched with the presence of black holes near the center of the cluster.
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The Case for a Small Universe

By Brian Koberlein - September 09, 2023 02:52 PM UTC | Cosmology
Astronomers don't know if the Universe is finite or infinite. Whatever the case, it's larger than the Observable Universe, which measures 93 billion light-years across. A new paper proposes that the actual Universe is comparatively tiny, not much bigger than its observed size - just a few orders of magnitude larger. A smaller Universe solves some problems with other theories of cosmology, including inflation and the amount of dark energy in the Universe.
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Should the Next Big Observatories Be Built on the Moon?

By Brian Koberlein - September 08, 2023 12:48 PM UTC | Telescopes
As the next round of giant observatories nears completion, astronomers are starting to ponder what comes next. One exciting location to consider is the Moon. There's no atmosphere on the Moon, so a lunar telescope would act like a space telescope. Still, solid ground, lower gravity, and potentially human astronauts are available to do maintenance and make upgrades. A new paper reviews different kinds of telescopes that could be built on the Moon and their unique advantages over Earth- or space-based instruments.
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The Most Distant Galactic Field Lines Ever Seen

By Brian Koberlein - September 07, 2023 11:25 AM UTC | Extragalactic
Galaxies are surrounded by magnetic field lines, spanning tens of thousands of light-years. These magnetic fields have previously been measured surrounding only the closest galaxies. Still, astronomers have made the map of a galaxy seen just a few billion years after the Big Bang. Astronomers discovered with ALMA, searching dust grains in the galaxy that align with the nearby magnetic fields. The light they emit becomes polarized, which can then be turned into magnetic field maps.
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Humanity Will Out-Communicate all Life on Earth Within 90 Years

By Brian Koberlein - September 06, 2023 10:36 AM UTC | Astrobiology
All organisms communicate information with their cells using signaling molecules. Add up all these communications, and it's the equivalent of 10^24 bits per second, which is an incomprehensibly large amount. Humanity's digital communication only amounts to 10^15 bits per second, nine orders of magnitude less. However, humanity's information transmission is growing exponentially, and according to a new study, it should catch up within 90 years. These estimates could help astronomers search for technological civilizations more advanced than us.
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A New Telescope Could Detect Decaying Dark Matter in the Early Universe

By Brian Koberlein - September 05, 2023 01:14 PM UTC | Cosmology
A gap in astronomical knowledge is Cosmic Dawn, a time when the first stars in the Universe formed, ending the cosmological dark ages. If there was dark matter at this early time, its decay might have heated up the intergalactic medium, sending out a signal that could be detectable today. A new paper suggests that the newly built Hydrogen Epoch of Reionization Array (HERA) telescope could measure this dark matter decay with 1,000 hours of observation or constrain its presence by three orders of magnitude.
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It's Going to Take More Than Early Dark Energy to Resolve the Hubble Tension

By Brian Koberlein - September 04, 2023 03:00 PM UTC | Cosmology
Astronomers have measured the Universe's expansion rate and found that various methods don't agree, and their error bars don't overlap. This is called the "Hubble Tension" or the "Crisis in Cosmology." Either the measurements are wrong, or new physics is waiting to be discovered. Cosmologists have proposed a period of rapid expansion early on in the Universe called "Early Dark Energy." Still, a recent paper suggests one rapid expansion event wouldn't explain other observations about the Universe. It's probably a combination of factors.
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The Closest Supernova Seen in the Modern Era, Examined by JWST

By Brian Koberlein - September 03, 2023 10:40 AM UTC | Extragalactic
In 1987, a supernova suddenly appeared in the Large Magellanic Cloud and was studied by astronomers worldwide. Although the detonating star was 165,000 light-years away, this was still the closest supernova seen in centuries. Astronomers have continued to study the expanding debris cloud over the decades, and now JWST has joined the effort, revealing new features never before seen with other observatories. The central core is so dense with gas and dust that its central neutron star remnant is still hidden, even to JWST.
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Astronomers are Hoping the Event Horizon Telescope saw Pulsars Near the Milky Way's Supermassive Black Hole

By Brian Koberlein - September 02, 2023 09:55 AM UTC | Black Holes
The Event Horizon Telescope is a collection of radio telescopes across the globe that simultaneously gathered data about the Milky Way's supermassive black hole, acting as a single telescope the size of planet Earth. This revealed the galaxy's heart in unprecedented detail, helping to confirm the black hole's event horizon and prove some of Einstein's predictions about General Relativity. But if those observations happened to contain any signals from pulsars in the area, it would allow for even more precise measurements, as if there were atomic clocks orbiting Sgr A*.
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If Earth Was an Exoplanet, JWST Would Know There's an Intelligent Civilization Here

By Brian Koberlein - September 01, 2023 11:51 AM UTC | Astrobiology
JWST is the most powerful instrument astronomers have to study the atmospheres of exoplanets, looking for trace gases that might indicate life on another world. What if Earth was an exoplanet orbiting a nearby star? What could JWST learn about our planet? In a new study, astronomers took observations of Earth from various spacecraft and then simulated what JWST would see if it got our home planet in the crosshairs. The telescope could detect various chemicals, from water vapor to methane, but it could also sense the presence of chlorofluorocarbons resulting from our industrial infrastructure.
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Do Advanced Civilizations Know We're Here?

By Brian Koberlein - August 31, 2023 10:41 AM UTC | Astrobiology
Although humans have only sent a couple of tentative signals into space, many are concerned about the risks. Should we let alien civilizations know we're here? According to a new paper, humanity has already been broadcasting its existence for thousands of years, and civilizations with advanced enough technology should be able to observe us. It's science fiction to us, but megastructure space telescopes could have baselines of millions of kilometers, powerful enough to detect structures on the surface of Earth from thousands of light-years away.
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It's Time for a Gravitational Wave Observatory in the Southern Hemisphere

By Brian Koberlein - August 30, 2023 10:48 AM UTC | Physics
All current and planned gravitational wave observatories are located in the northern hemisphere, in the US, India, Europe, and Japan. Even the next-generation observatories like Cosmic Explorer 40-km and the Einstein Telescope will be in the north. But a telescope in the southern hemisphere would provide a much larger baseline, allowing the detection of fainter gravitational waves. A new paper makes the case for building an observatory south of the equator.
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