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A New Telescope Could Detect Decaying Dark Matter in the Early Universe

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

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

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

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

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?

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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Astronomers Precisely Measure a Black Hole's Accretion Disk

Actively feeding supermassive black holes are known as quasars, and they can outshine all the stars of their host galaxy. Part of their brightness comes from the accretion disk surrounding the black hole, but they’re hard to image directly because quasars are so far away. New data from one of the world’s largest telescopes has managed this feat, detecting near-infrared emission lines that mark significant regions in the accretion disk in a quasar.

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Pulsars Detected the Background Gravitational Hum of the Universe. Now Can They Detect Single Mergers?

After over a decade of observations of pulsars, astronomers could finally tease out the gravitational wave background of the Universe, the combined signal from merging supermassive black holes. But it was just the general presence of mergers, not specific events. A new paper proposes that the same pulsars could next be used to detect the gravitational waves from individual merging supermassive black holes. The more nearby pulsars astronomers can find, the more accurate their measurements will become.

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A Giant Black Hole Destroyed a Star and Threw the Pieces Into Space

A pair of X-ray telescopes have observed the messy aftermath of a star that came too close to a supermassive black hole 290 million light-years away. It’s believed that the star had three times the mass of the Sun, so this was one of the largest tidal disruption events ever seen. Although the black hole consumed some of the star, most of its guts were thrown into the surrounding space, polluting the region with the chemicals that allowed astronomers to estimate its stellar mass.

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A New Way to Measure the Expansion Rate of the Universe: Redshift Drift

Almost all the galaxies in the Universe are speeding away from us because of the Big Bang and the acceleration of dark energy. One technique to measure this expansion is redshift, seeing how light is reddened over time as its wavelength stretches out. But every observation astronomers can make is a snapshot, measuring the redshift now. But an intriguing idea is to measure how the redshift changes over time as a galaxy’s movement accelerates. It’s called “redshift drift” and requires an exact series of measurements over time.