Brian Koberlein, Author at Universe Today

April 27, 2021April 27, 2021 by Brian Koberlein

Smallest, Closest Black Hole Ever Discovered is Only 1,500 Light-Years Away

Artist concept of V723 Mon and its companion. Lauren Fanfer/Ohio State

In theory, a black hole is easy to make. Simply take a lump of matter, squeeze it into a sphere with a radius smaller than the Schwarzschild radius, and poof! You have a black hole. In practice, things aren’t so easy. When you squeeze matter, it pushes back, so it takes a star’s worth of weight to squeeze hard enough. Because of this, it’s generally thought that even the smallest black holes must be at least 5 solar masses in size. But a recent study shows the lower bound might be even smaller.

April 25, 2021April 25, 2021 by Brian Koberlein

A new Technique Could use Quasars to Directly Measure the Expansion Rate of the Universe

an artistic concept of a quasar — Concept image of a galactic quasar. Astronomers used the Event Horizon Telescope to study details at the heart of one like this called NRAO 530. Credit: ParallelVision, Pixabay

One of the biggest challenges to measuring the expansion of the universe is the fact that many of the methods we use are model-dependent. The most famous example is the use of distant supernovae, where we compare the standard brightness of a Type Ia supernova with their apparent brightness to find their distance. But knowing the standard brightness depends upon comparing them to the brightness of Cepheid variables which is in turn determined by measuring the distances of nearby stars via parallax. Every step of this cosmic distance ladder depends upon the step before it.

April 20, 2021April 20, 2021 by Brian Koberlein

One Idea to Explain Dark Matter – Ultralight Bosons – Fails the Test

Dr. Kip Thorne made it clear that black is not the primary hue of Black Holes. His guidance offered to Nolan raised science fiction to a new level. Credit: Paramount Pictures/Warner Bros.

Dark matter continues to resist our best efforts to pin it down. While dark matter remains a dominant theory of cosmology, and there is lots of evidence to support a universe filled with cold dark matter, every search for dark matter particles yields nothing. A new study continues that tradition, ruling out a range of dark matter candidates.

April 17, 2021April 17, 2021 by Brian Koberlein

You Thought Black Hole Event Horizons Looked Strange. Check out Binary Black Hole Event Horizons

The lensing effects can be complex and difficult to calculate. Credit: NASA’s Goddard Space Flight Center/Jeremy Schnittman and Brian P. Powell

One of the strangest predictions of general relativity is that gravity can deflect the path of light. The effect was first observed by Arthur Eddington in 1919. While the bending effect of the Sun is small, near a black hole light deflection can be significant. So significant that you need a powerful supercomputer to calculate how light will behave.

April 14, 2021April 14, 2021 by Brian Koberlein

Finding Oxygen on an Alien World Doesn't Always Mean There's Life There

Artist concept of the planetary system Kepler 62. Credit: Danielle Futselaar - SETI Institute

We now know the universe is filled with planets. By one estimate, there are more than 20 billion Earth-like worlds in our galaxy alone. But how many of them are likely to have life? And how would we know if they do? Unless they happen to send us a very clear message directly, the most likely way we’ll discover exoplanet life is by looking at their atmospheres.

April 12, 2021April 12, 2021 by Brian Koberlein

Brown Dwarfs can Spin so Fast They Almost Tear Themselves Apart

Comparing the rotation of a brown dwarf with Jupiter and Saturn. Credit: Robert Hurt (IPAC/Caltech)

We tend to image planets as spheres. Held together by gravity, the material of a planet compresses and shifts until gravity and pressure reach a balance point known as hydrostatic equilibrium. Hydrostatic equilibrium is one of the defining characteristics of a planet. If a planet were stationary and of uniform density, then at equilibrium, it would be a perfect sphere. But planets rotate, and so even the largest planets aren’t a perfect sphere.

April 10, 2021April 10, 2021 by Brian Koberlein

Primordial Asteroids That Never Suffered Massive Collisions all Seem to be Larger Than 100 km. Why?

2004 EW95, seen in this artist view, may be a primordial asteroid. Credit: M. Kornmesser/European Southern Observatory

Planetary systems form out of the remnant gas and dust of a primordial star. The material collapses into a protoplanetary disk around the young star, and the clumps that form within the disk eventually become planets, asteroids, or other bodies. Although we understand the big picture of planetary formation, we’ve yet to fully understand the details. That’s because the details are complicated.

April 8, 2021April 8, 2021 by Brian Koberlein

An Intermediate-Mass Black Hole Discovered Through the Gravitational Lensing of a Gamma-ray Burst

An intermediate mass black hole lenses light around it. Credit: Carl Knox, OzGrav

Black holes come in three sizes: small, medium, and large. Small black holes are of stellar mass. They form when a large star collapses at the end of its life. Large black holes lurk in the centers of galaxies and are millions or billions of solar masses. Middle-sized black holes are those between 100 to 100,000 solar masses. They are known as Intermediate Mass Black Holes (IMBHs), and they are the kind we least understand.

April 4, 2021April 4, 2021 by Brian Koberlein

A new way to see Inside Neutron Stars

The song of a binary tells us about neutron stars. Credit: University of Bath

Imagine trying to study an object light-years away that is less than 20 kilometers in diameter. The object is so dense that it’s made of material that can’t exist naturally on Earth. This is the challenge astronomers face when studying neutron stars, so they have to devise ingenious ways to do it. Recently a team figured out how to study them by using the power of resonance.

March 27, 2021March 27, 2021 by Brian Koberlein

The Event Horizon Telescope has Revealed the Magnetic Field Lines Around M87's Central Black Hole

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

In 2019 astronomers captured the first direct image of a black hole. It was an image of the supermassive black hole at the heart of M87. And when many folks saw it, their reaction was “that’s it?” Which is understandable, given that the image is just a blurry, donut-shaped smudge. It isn’t much to look at. But an astronomical image is a small fraction of the data gathered by astronomers. Recently more of that data has been analyzed, including both the polarization of the light and the magnetic field surrounding the black hole.