Brian Koberlein, Author at Universe Today

August 18, 2021August 18, 2021 by Brian Koberlein

You can Tell how big a Black Hole is by how it Eats

An artist’s impression of an accretion disk rotating around an unseen supermassive black hole. Credit: Mark A. Garlick/Simons Foundation

Black holes don’t emit light, which makes them difficult to study. Fortunately, many black holes are loud eaters. As they consume nearby matter, surrounding material is superheated. As a result, the material can glow intensely, or be thrown away from the black hole as relativistic jets. By studying the light from this material we can study black holes. And as a recent study shows, we can even determine their size.

August 15, 2021August 15, 2021 by Brian Koberlein

If the First Black Holes Collapsed Directly, Could we Detect Radio Signals From Those Moments?

This artist’s impression shows a possible seed for the formation of a supermassive black hole. Credit: NASA/CXC/M. Weiss

The universe is littered with supermassive black holes. There’s one a mere 30,000 light-years away in the center of the Milky Way. Most galaxies have one, and some of them are more massive than a billion stars. We know that many supermassive black holes formed early in the universe. For example, the quasar TON 618 is powered by a 66 billion solar mass black hole. Since its light travels nearly 11 billion years to reach us, TON 618 was already huge when the universe was just a few billion years old. So how did these black holes grow so massive so quickly?

August 14, 2021August 14, 2021 by Brian Koberlein

Matter From Light. Physicists Create Matter and Antimatter by Colliding Just Photons.

An artistic view of light becoming matter. Credit: Gerd Altmann, via Pixabay

In 1905 Albert Einstein wrote four groundbreaking papers on quantum theory and relativity. It became known as Einstein’s annus mirabilis or wonderous year. One was on brownian motion, one earned him the Nobel prize in 1921, and one outlined the foundations of special relativity. But it’s Einstein’s last 1905 paper that is the most unexpected.

August 11, 2021August 11, 2021 by Brian Koberlein

Astronomers Find a Nearby Star That a Spitting Image of a Young Sun

Illustration of what the Sun may have been like 4 billion years ago. Credit: NASA's Goddard Space Flight Center/Conceptual Image Lab

Our Sun is about 4.6 billion years old. We know that from models of Sun-like stars, as well as through our observations of other stars of similar mass. We know that the Sun has grown hotter over time, and we know that in about 5 billion years it will become a red giant star before ending its life as a white dwarf. But there are many things about the Sun’s history that we don’t understand. How active was it in its youth? What properties of the young Sun allowed life to form on Earth billions of years ago?

August 7, 2021August 7, 2021 by Brian Koberlein

Good News! Red Dwarfs Blast Their Superflares out the Poles, Sparing Their Planets From Destruction

The only known life in the universe lives on a mid-size rocky planet that orbits a mid-size yellow star. That makes our planet a bit unusual. While small rocky planets are common in the galaxy, yellow stars are not. Small red dwarf stars are much more typical, making up about 75% of the stars in the Milky Way. This is why most of the potentially habitable exoplanets we’ve discovered orbit red dwarfs.

July 25, 2021July 25, 2021 by Brian Koberlein

A Gravitational Wave Observatory on the Moon Could "Hear" 70% of the Observable Universe

Concept for a Gravitational-wave Lunar Observatory for Cosmology (GLOC). Credit: Jani, et al

Gravitational-wave astronomy is set to revolutionize our understanding of the cosmos. In only a few years it has significantly enhanced our understanding of black holes, but it is still a scientific field in its youth. That means there are still serious limitations to what can be observed.

July 7, 2021July 7, 2021 by Brian Koberlein

The "Crisis in Cosmology" Might not be a Crisis After all

Climbing the cosmic distance ladder. Credit: NASA/JPL-Caltech/R. Hurt (IPAC)

The standard model of cosmology is known as the LCDM model. Here, CDM stands for Cold Dark Matter, which makes up most of the matter in the universe, and L stands for Lambda, which is the symbol used in general relativity to represent dark energy or cosmic expansion. While the observational evidence we have largely supports the LCDM model, there are some issues with it. One of the most bothersome is known as cosmic tension.

July 5, 2021July 5, 2021 by Brian Koberlein

Hawking Made a Prediction About Black Holes, and Physicists Just Confirmed it

Computer simulation of plasma near a black hole. Credit: Hotaka Shiokawa / EHT

On its own, a black hole is remarkably easy to describe. The only observable properties a black hole has are its mass, its electric charge (usually zero), and its rotation, or spin. It doesn’t matter how a black hole forms. In the end, all black holes have the same general structure. Which is odd when you think about it. Throw enough iron and rock together and you get a planet. Throw together hydrogen and helium, and you can make a star. But you could throw together grass cuttings, bubble gum, and old Harry Potter books, and you would get the same kind of black hole that you’d get if you just used pure hydrogen.

July 1, 2021July 1, 2021 by Brian Koberlein

Astronomers Detected a Black Hole-Neutron Star Merger, and Then Another Just 10 Days Later

An artistic image inspired by a black hole-neutron star merger event. Credit: Carl Knox, OzGrav/Swinburne

The interior of a neutron star is perhaps the strangest state of matter in the universe. The material is squeezed so tightly that atoms collapse into a sea of nuclear material. We still aren’t sure whether nucleons maintain their integrity in this state, or whether they dissolve into quark matter. To really understand neutron star matter we need to pull it apart to see how it works and to do that takes a black hole. This is why astronomers are excited about the recent discovery of not one, but two mergers between a neutron star and a black hole.

June 29, 2021June 29, 2021 by Brian Koberlein

A Lunar Farside Telescope Could Detect Exoplanets Through Their Magnetospheres

It’s difficult to do radio astronomy on Earth, and it’s getting harder every day. Our everyday reliance on radio technology means that radio interference is a constant challenge, even in remote areas. And for some wavelengths even the Earth’s atmosphere is a problem, absorbing or scattering radio light so that Earth-based telescopes can’t observe these wavelengths well. To overcome these challenges, astronomers have proposed putting a radio telescope on the far side of the Moon.