Brian Koberlein, Author at Universe Today

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.

June 27, 2021June 27, 2021 by Brian Koberlein

Gravitational-Wave Detector Could Sense Merging Primordial Black Holes With the Mass of a Planet, Millions of Light-Years Away

Simulation of the gravitational waves of merging black holes. Credit: N. Fischer, H. Pfeiffer, A. Buonanno (Max Planck Institute for Gravitational Physics), Simulating eXtreme Spacetimes (SXS) Collaboration

Gravitational-wave detectors have been a part of astronomy for several years now, and they’ve given us a wealth of information about black holes and what happens when they merge. Gravitational-wave astronomy is still in its infancy, and we are still very limited in the type of gravitational waves we can observe. But that could change soon.

June 25, 2021June 25, 2021 by Brian Koberlein

Could Life Exist in the Atmosphere of a sub-Neptune Planet?

An illustration of the Kepler-47 circumbinary planet system. Credit: NASA/JPL Caltech/T. Pyle

Earth is perfectly suited for organic life. It stands to reason then that similar worlds orbiting distant stars might also be rich with life. But proving it will be a challenge. One of the better ways to discover extraterrestrial life will be to study the atmospheres of inhabited exoplanets, but Earth is fairly small for a planet and has a thin atmosphere compared to larger worlds. It will be much easier to study the atmospheres of gas planets, but could such worlds harbor life? A new paper in Universe argues it could.

June 23, 2021June 23, 2021 by Brian Koberlein

Betelgeuse's Mysterious Dimming Solved. It was… Dust

Artist's impression of Betelgeuse. Credit: ESO/L. Calçada

At the beginning of 2020, the red giant star Betelgeuse started to dim significantly. Betelgeuse has been known to vary in brightness, but this one was unusual. It grew much dimmer than usual, and for a longer period. Since Betelgeuse is a star at the end of its life, it led some to speculate that perhaps it would go supernova. Astronomers didn’t think that was likely, and of course, Betelgeuse didn’t explode, and gradually its usual brightness returned. But astronomers were puzzled as to why Betelgeuse grew so dim.