Brian Koberlein, Author at Universe Today

March 16, 2022March 16, 2022 by Brian Koberlein

A new way to Confirm Hawking's Idea That Black Holes Give off Radiation

In honor of Dr. Stephen Hawking, the COSMOS center will be creating the most detailed 3D mapping effort of the Universe to date. Credit: BBC, Illus.: T.Reyes

Nothing can escape a black hole. General relativity is very clear on this point. Cross a black hole’s event horizon, and you are forever lost to the universe. Except that’s not entirely true. It’s true according to Einstein’s theory, but general relativity is a classical model. It doesn’t take into account the quantum aspects of nature. For that, you’d need a quantum theory of gravity, which we don’t have. But we do have some ideas about some of the effects of quantum gravity, and one of the most interesting is Hawking radiation.

March 14, 2022March 14, 2022 by Brian Koberlein

If Axions are Dark Matter, we've got new Hints About Where to Look for Them

Artist rendering of the dark matter halo surrounding our galaxy. For quasars, the dark matter halos are much more massive. Credit: ESO/L. Calçada — Artist rendering of the dark matter halo surrounding our galaxy. Credit: ESO/L. Calçada

If dark matter is out there, and it certainly seems to be, then what could it possibly be? That is perhaps the biggest mystery of dark matter. The only known particles that match the requirement of having mass and not interacting strongly with light are neutrinos. But neutrinos have low mass and zip through the cosmos at nearly the speed of light. They are a form of “hot” dark matter, so they don’t match the observed data that require dark matter to be “cold.” With neutrinos ruled out, cosmologists look toward various hypothetical particles we haven’t discovered, and perhaps the most popular of these are known as axions.

March 11, 2022March 11, 2022 by Brian Koberlein

Neutron Stars Could be the Best way to Measure Dark Energy

An artistic rendering of two neutron stars merging. Credit: NSF/LIGO/Sonoma State/A. Simonnet

Dark energy is central to our modern theory of cosmology. We know the universe is expanding at an ever-increasing rate, and the clearest explanation is that some kind of energy is driving it. Since this energy doesn’t emit light, we call it dark energy. But simply giving dark energy a name doesn’t mean we fully understand it. We can see what dark energy does, but its fundamental nature is perhaps the biggest scientific mystery we have.

February 14, 2022February 14, 2022 by Brian Koberlein

Astronomers see Dead Planets Crashing Into Dead Stars

Artist’s impression of a white dwarf accreting planetary material from a circumstellar debris disk. Credit: University of Warwick/Mark Garlick

When our Sun dies, the Earth will die with it. As a star of middling mass, the Sun will end its life by swelling into a red giant star. After a last cosmic moment of brilliance, the remnant core of the Sun will collapse into a white dwarf. This won’t occur for billions of years, but the mass and composition of the Sun means a white dwarf is its inevitable fate.

February 8, 2022February 8, 2022 by Brian Koberlein

Why are Neptune and Uranus Different Colors?

A comparison of Uranus (left) and Neptune (right). Credit: Left: NASA/JPL-Caltech, Right: NASA

Uranus and Neptune are similar planets in many ways. Both are ice giant worlds, both have atmospheres rich in methane, and both have a bluish color. But while Uranus has a pale blue-green hue, Neptune has a deep blue color. But why? Why would two planets so similar in size and composition appear so different? According to a recent study, the answer lies in their aerosols.

January 31, 2022January 31, 2022 by Brian Koberlein

Binary Black Holes can Unlock Another of Einstein’s Predictions

Artist view of a binary black hole system. Credit: LIGO/Caltech/MIT/Sonoma State (Aurore Simonnet)

In the grand scheme of things, the structure of a black hole is pretty simple. All you need to know is its mass, electric charge, and rotation, and you know what the structure of space and time around the black hole must be. But if you have two black holes orbiting each other, then things get really complicated. Unlike a single black hole, for which there is an exact solution to Einstein’s equations, there is no exact solution for two black holes. It’s similar to the three-body problem in Newtonian gravity. But that doesn’t mean astronomers can’t figure things out, as a couple of recent studies show.

January 29, 2022January 29, 2022 by Brian Koberlein

Astronomers Discover a Mysterious Star That Flashes Every 20 Minutes. But What is it?

A radio map of the Milky Way showing the location of the new transient. Credit: Dr Natasha Hurley-Walker (ICRAR/Curtin) and the GLEAM Team

Just 4,000 light-years from Earth is a strange, star-sized object. It’s been observed by radio telescopes, but astronomers aren’t sure what it is. They call it a long period transient.

January 24, 2022January 24, 2022 by Brian Koberlein

Extreme Tidal Forces Have Deformed an Exoplanet

Among the thousands of known exoplanets, there are some that are very odd. Take, for example, the exoplanet known as WASP-103b. It’s a large planet with a mass about 1.5 times that of Jupiter, but 103b is so close to its star it makes a complete orbit every 22 hours. At this proximity, many astronomers wonder if the world is on the edge of being ripped apart by tidal forces. But a new study shows us that something much more interesting is going on.

January 23, 2022January 23, 2022 by Brian Koberlein

A Worldwide Search for Dark Matter Fails to Turn up a Signal for This Mysterious Particle

Simulation of dark matter and gas. Credit: Illustris Collaboration (CC BY-SA 4.0)

Axions are a popular candidate in the search for dark matter. There have been previous searches for these hypothetical particles, all of which have come up with nothing. But recently the results of a new search for dark matter axions have been published…and has also found nothing. Still, the study is interesting because of the nature and scale of the search.

January 19, 2022January 19, 2022 by Brian Koberlein

A new Kind of Supernova has Been Discovered

Hen 2-427, a Wolf–Rayet star. Credit: ESA/Hubble & NASA, Judy Schmidt

We often think of supernova explosions as inevitable for large stars. Big star runs out of fuel, gravity collapses its core and BOOM! But astronomers have long thought at least one type of large star didn’t end with a supernova. Known as Wolf-Rayet stars, they were thought to end with a quiet collapse of their core into a black hole. But a new discovery finds they might become supernovae after all.