Brian Koberlein, Author at Universe Today

November 18, 2024November 18, 2024 by Brian Koberlein

The Large Magellanic Cloud Survived its Closest Approach to the Milky Way

Illustration of the Large Magellanic Cloud passing through the halo of the Milky Way. Credit: NASA, ESA, Ralf Crawford (STScI)

The Large Magellanic Cloud is a small galaxy, just a tenth of the Milky Way’s mass. It is about 160,000 light years away, which is remarkably close in cosmic terms. In the southern hemisphere it spans the width of 20 Moons in the night sky. While the galaxy seems timeless and unchanging to our short human lives, it is, in fact, a dynamic system undergoing a near collision with our galaxy. Now astronomers are beginning to observe that process.

November 16, 2024November 16, 2024 by Brian Koberlein

Detecting Primordial Black Hole Mergers Might be Within Our Grasp

An artistic take on primordial black holes. Credit: NASA’s Goddard Space Flight Center

Imagine a black hole with the mass of the asteroid Ceres. It would be no larger than a bacterium and practically undetectable. But if such black holes are common in the Universe, they would affect the motions of stars and galaxies, just as we observe. Perhaps they are the source of dark matter.

November 15, 2024November 15, 2024 by Brian Koberlein

The Best Way to Find Planet Nine Might Be Hundreds of Tiny Telescopes

Artist's impression of Planet Nine as an ice giant eclipsing the central Milky Way, with a star-like Sun in the distance. Neptune's orbit is shown as a small ellipse around the Sun. The sky view and appearance are based on the conjectures of its co-proposer, Mike Brown.

Ever since William Herschel discovered Uranus in 1781, astronomers have been eager to find new planets on the outer edge of the solar system. But after the discovery of Neptune in 1846, we’ve found no other large planets. Sure, we discovered Pluto and other dwarf planets beyond it, but nothing Earth-sized or larger. If there is some planet nine, or “Planet X” lurking out there, we have yet to find it.

November 15, 2024November 15, 2024 by Brian Koberlein

A New Look a the Most Ancient Light in the Universe

The South Pole Telescope observes the southern winter sky. Credit: Aman Chokshi

In the earliest moments of the Universe, the first photons were trapped in a sea of ionized gas. They scattered randomly with the hot nuclei and electrons of the cosmic fireball, like tiny boats in a stormy sea. Then, about 370,000 years after the big bang, the Universe cooled enough for the photons to be free. After one last scattering, they could finally ply interstellar space. Some of them traveled across 14 billion years of space and time to reach Earth, where we see them as part of the cosmic microwave background. The remnant first light of creation.

November 14, 2024November 14, 2024 by Brian Koberlein

Two Supermassive Black Holes on the Verge of a Merger

A pair of monster black holes swirl in a cloud of gas in this artist’s concept of AT 2021hdr. Credit: NASA/Aurore Simonnet (Sonoma State University)

In March 2021, astronomers observed a high-energy burst of light from a distant galaxy. Assigned the name AT 2021hdr, it was thought to be a supernova. However, there were enough interesting features that flagged as potentially interesting by the Automatic Learning for the Rapid Classification of Events (ALeRCE). In 2022, another outburst was observed, and over time the Zwicky Transient Facility (ZTF) found a pattern of outbursts every 60–90 days. It clearly wasn’t a supernova, but it was unclear on what it could be until a recent study solved the mystery.

November 14, 2024November 14, 2024 by Brian Koberlein

Astronomers Map the Shape of a Black Hole's Corona for the First Time

Illustration of material swirling around a black hole highlights the corona, that shines brightly in X-ray light. Credit: NASA/Caltech-IPAC/Robert Hurt

If you were lucky enough to observe a total eclipse, you are certain to remember the halo of brilliant light around the Moon during totality. It’s known as the corona, and it is the diffuse outer atmosphere of the Sun. Although it is so thin we’d consider it a vacuum on Earth, it has a temperature of millions of degrees, which is why it’s visible during a total eclipse. According to our understanding of black hole dynamics black holes should also have a corona. And like the Sun’s corona, it is usually difficult to observe. Now a study in The Astrophysical Journal has made observations of this elusive region.

November 13, 2024November 13, 2024 by Brian Koberlein

Astronomers Defy the Zone of Avoidance to Find Hundreds of New Galaxies

A rendered image of the Milky Way based on the Gaia EDR3 dataset. Credit: Wikipedia user Kevinmloch

There is a region of the sky where astronomers fear to look. Filled with dark clouds of dust, it hides an unseen mass. A mass so large it is pulling the Milky Way and other galaxies toward it…

November 10, 2024November 10, 2024 by Brian Koberlein

How Webb Stays in Focus

A focused NIRCam image compared to intentionally de-focused ones. Credit: NASA/JWST

One of the most difficult challenges when assembling a telescope is aligning it to optical precision. If you don’t do it correctly, all your images will be fuzzy. This is particularly challenging when you assemble your telescope in space, as the James Webb Space Telescope (JWST) demonstrates.

November 9, 2024November 9, 2024 by Brian Koberlein

Using Light Echoes to Find Black Holes

Light near a black hole can travel different paths to create echoes of a single flash. Credit: Wong, et al

The most amazing thing about light is that it takes time to travel through space. Because of that one simple fact, when we look up at the Universe we see not a snapshot but a history. The photons we capture with our telescopes tell us about their journey. This is particularly true when gravity comes into play, since gravity bends and distorts the path of light. In a recent study, a team shows us how we might use this fact to better study black holes.

November 8, 2024November 8, 2024 by Brian Koberlein

An Explanation for Rogue Planets. They Were Eroded Down by Hot Stars

Illustration of a Jupiter-mass binary object. Credit: Gemini Observatory/Jon Lomberg

The dividing line between stars and planets is that stars have enough mass to fuse hydrogen into helium to produce their own light, while planets aren’t massive enough to produce core fusion. It’s generally a good way to divide them, except for brown dwarfs. These are bodies with a mass of about 15–80 Jupiters, so they are large enough to fuse deuterium but can’t generate helium. Another way to distinguish planets and stars is how they form. Stars form by the gravitational collapse of gas and dust within a molecular cloud, which allows them to gather mass on a short cosmic timescale. Planets, on the other hand, form by the gradual accumulation of gas and dust within the accretion disk of a young star. But again, that line becomes fuzzy for brown dwarfs.