Posted on by Brian Koberlein

Neutron Stars With Less Mass Than A White Dwarf Might Exist, and LIGO and Virgo Could Find Them

Illustration of a neutron star. Credit: NASA’s Goddard Space Flight Center/Chris Smith (USRA/GESTAR)

Most of the neutron stars we know of have a mass between 1.4 and 2.0 Suns. The upper limit makes sense, since, beyond about two solar masses, a neutron star would collapse to become a black hole. The lower limit also makes sense given the mass of white dwarfs. While neutron stars defy gravitational collapse thanks to the pressure between neutrons, white dwarfs defy gravity thanks to electron pressure. As first discovered by Subrahmanyan Chandrasekhar in 1930, white dwarfs can only support themselves up to what is now known as the Chandrasekhar Limit, or 1.4 solar masses. So it’s easy to assume that a neutron star must have at least that much mass. Otherwise, collapse would stop at a white dwarf. But that isn’t necessarily true.

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Posted on by Matt Williams

Webb Observes Protoplanetary Disks that Contradict Models of Planet Formation

Image of the star cluster NGC 346, captured by Webb's Near-Infrared Camera (NIRCam). Credit: NASA, ESA, CSA, STScI, Olivia C. Jones (UK ATC), Guido De Marchi (ESTEC), Margaret Meixner (USRA)

The James Webb Space Telescope (JWST) was specifically intended to address some of the greatest unresolved questions in cosmology. These include all of the major questions scientists have been pondering since the Hubble Space Telescope (HST) took its deepest views of the Universe: the Hubble Tension, how the first stars and galaxies came together, how planetary systems formed, and when the first black holes appeared. In particular, Hubble spotted something very interesting in 2003 when observing a star almost as old as the Universe itself.

Orbiting this ancient star was a massive planet whose very existence contradicted accepted models of planet formation since stars in the early Universe did not have time to produce enough heavy elements for planets to form. Thanks to recent observations by the JWST, an international team of scientists announced that they may have solved this conundrum. By observing stars in the Small Magellanic Cloud (LMC), which lacks large amounts of heavy elements, they found stars with planet-forming disks that are longer-lived than those seen around young stars in our Milky Way galaxy.

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Posted on by Andy Tomaswick

A Mission to Dive Titan’s Lakes – and Soar Between Them

Titan is one of the solar system’s most fascinating worlds for several reasons. It has something akin to a hydrological cycle, though powered by methane. It is the solar system’s second-largest moonMooner our own. It is the only other body with liquid lakes on its surface. That’s part of the reason it has attracted so much attention, including an upcoming mission known as Dragonfly that hopes to use its thick atmosphere to power a small helicopter. But some of the most interesting features on Titan are its lakes, and Dragonfly, given its means of locomotion, can’t do much with those other than look at them from afar. So another mission, initially conceived by James McKevitt, then an undergraduate at Loughborough University but now a PhD student at University College London would take a look at both their surface and underneath.

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Posted on by David Dickinson

Top Astronomy Events for 2025

Catching the best sky watching events for the coming year 2025.

Comet vs solar scope
Comet C/2023 A3 Tsuchinshan-ATLAS captured over the McMath-Pierce Solar Telescope at Kitt Peak National Observatory, Arizona. Credit: Robert Sparks

How about that eclipse in 2024? Certainly, the Great North American Eclipse of April 8th 2024 was one for the ages, instilling the eclipse-chasing bug in many a new skywatching fan. Now, for the bad news: 2025 is a rare, totality free year, featuring only a pair of remote partial solar eclipses. The good news is, there’s lots more in store to see in the sky in 2025, with a pair of fine total lunar eclipses, Mars at its best, and lunar occultations galore. And hey, the Sun is still mighty active, and the cosmos does still owe us another fine comet.

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Posted on by Brian Koberlein

How Did Black Holes Grow So Quickly? The Jets

Artist’s impression of a bright, very early active galactic nucleus. Credit: NSF/AUI/NSF NRAO/B. Saxton

Within nearly every galaxy is a supermassive black hole. The beast at the heart of our galaxy contains the mass of millions of suns, while some of the largest supermassive black holes can be more than a billion solar masses. For years, it was thought that these black holes grew in mass over time, only reaching their current size after a billion years or more. But observations from the Webb telescope show that even the youngest galaxies contain massive black holes. So how could supermassive black holes grow so large so quickly? The key to the answer could be the powerful jets black holes can produce.

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Posted on by Paul M. Sutter

Quantum Correlations Could Solve the Black Hole Information Paradox

Artist view of a black hole ringing down into a stable state. Credit: Yasmine Steele at University of Illinois – Urbana Champaign

The black hole information paradox has puzzled physicists for decades. New research shows how quantum connections in spacetime itself may resolve the paradox, and in the process leave behind a subtle signature in gravitational waves.

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Posted on by Matt Williams

M87 Releases a Rare and Powerful Outburts of Gamma-ray Radiation

A Hubble Space Telescope image of the giant galaxy M87 shows a 3,000-light-year-long jet of plasma blasting from the galaxy's 6.5-billion-solar-mass central black hole. The blowtorch-like jet seems to cause stars to erupt along its trajectory. These novae are not caught inside the jet, but are apparently in a dangerous neighbourhood nearby. During a recent 9-month survey, astronomers using Hubble found twice as many of these novae going off near the jet as elsewhere in the galaxy. The galaxy is the home of several trillion stars and thousands of star-like globular star clusters. [Image description: A Hubble photo of galaxy M87, which resembles a translucent, fuzzy white cotton ball. The brightness decreases gradually out in all directions from a bright white point of light at the centre. A wavy blue-white jet of material extends from the point-like core outward to the upper right, about halfway across the galaxy. Stars speckle the background.]

In April 2019, the Event Horizon Telescope (EHT) collaboration made history when it released the first-ever image of a black hole. The image captured the glow of the accretion disk surrounding the supermassive black hole (SMBH) at the center of the M87 galaxy, located 54 million light-years away. Because of its appearance, the disk that encircles this SMBH beyond its event horizon (composed of gas, dust, and photons) was likened to a “ring of fire.” Since then, the EHT has been actively imaging several other SMBH, including Sagittarius A* at the center of the Milky Way!

In addition, the EHT has revealed additional details about M87, like the first-ever image of a photon ring and a picture that combines the SMBH and its relativistic jet emanating from its center. Most recently, the EHT released the results of its latest observation campaign. These observations revealed a spectacular flare emerging from M87’s powerful relativistic jet. This flare released a tremendous amount of energy in multiple wavelengths, including the first high-energy gamma-ray outburst observed in over a decade.

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Posted on by Scott Alan Johnston

Astronomers Find a Black Hole Tipped Over on its Side

Hubble Space Telescope image of galaxy NGC 5084’s core. A dark, vertical line near the center shows the curve of a dusty disk orbiting the core, whose presence suggests a supermassive black hole within. The disk and black hole share the same orientation, fully tipped over from the horizontal orientation of the galaxy. NASA/STScI, M. A. Malkan, B. Boizelle, A.S. Borlaff. HST WFPC2, WFC3/IR/UVIS.

Almost every large galaxy has a supermassive black hole churning away at its core. In most cases, these black holes spin in concert with their galaxy, like the central hub of a cosmic wagon wheel. But on December 18, 2024, NASA researchers announced they had discovered a galaxy whose black hole appears to have been turned on its side, spinning out of alignment with its host galaxy.

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