Brian Koberlein, Author at Universe Today

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.

January 18, 2022January 18, 2022 by Brian Koberlein

20% of Twilight Observations Contain Satellite Passes

Starlink trails and a meteor as seen from Brazil. Credit: Egon Filter

With the rapid expansion of commercial space, there is a growing number of satellites in orbit around our planet. Most of these are in low-Earth orbit, which is becoming increasingly crowded. This has led some to be concerned about a catastrophic rise of space debris, as well as a growing frustration by astronomers due to the number of satellite sky trails.

January 12, 2022January 12, 2022 by Brian Koberlein

The Milky Way’s Most Recent Meal was a Galaxy it Gobbled up 8-10 Billion Years ago

Gaia-Enceladus in a simulation of a galactic merger with the Milky Way matching Gaia data. Credit: ESA (artist’s impression and composition); Koppelman, Villalobos and Helmi (simulation)

A central aspect of galactic evolution is that they must eat or be eaten. Dark energy strives to push galaxies apart, but gravity tries to pull them together. As a result, galaxies tend to form into local groups. As these superclusters of galaxies become more isolated due to cosmic expansion, they gravitationally turn on each other, and in time the largest galaxies of the group will consume the smaller ones. The Milky Way is one of the larger galaxies in our local group, and so it has consumed smaller galaxies in the past. But piecing together the history of these galactic meals is a real challenge.

January 6, 2022January 6, 2022 by Brian Koberlein

Why don’t Green Comets Have Green Tails?

Comet C/2014 Q2 Lovejoy photographed overnight December 28-29, 2014 remotely from Siding Spring, Australia as passed within 1/6 degree of the globular cluster M79. The coma glows green from fluorescing carbon molecules while the narrow ion tail is carbon monoxide gas fluorescing in UV sunlight. Credit: Rolando Ligustri

Green is an unusual color in astronomy. It is the color to which our eyes are most sensitive, and yet few things in the night sky actually appear green. There are, for example, no green stars, only yellow-white, red, and blue ones. But there can be green comets, and we are still learning why.

December 29, 2021December 29, 2021 by Brian Koberlein

If you had Radio Telescopes for Eyes, one of the Biggest Things in the sky Would be a jet of Material Blasting out of a Nearby Galaxy

Merging X-ray data (blue) from NASA’s Chandra X-ray Observatory with microwave (orange) and visible images reveals the jets and radio-emitting lobes emanating from Centaurus A's central black hole. Credit: ESO/WFI (visible); MPIfR/ESO/APEX/A.Weiss et al. (microwave); NASA/CXC/CfA/R.Kraft et al. (X-ray)

One concept that’s difficult to visualize is the apparent size of objects in the sky. No the actual size of an object, but rather the amount of area an object covers in the sky. Apparent size depends on an object’s actual size and its distance from us. For example, the Sun is about 400 times wider than the Moon, but also about 400 times more distant, so the Sun and Moon have roughly the same apparent size.

December 24, 2021December 24, 2021 by Brian Koberlein

Primordial Black Holes Could Explain Dark Matter and the Growth of Supermassive Black Holes at the Same Time

How we might discover primordial black holes. Credit: ESA

It’s that time again. Time to look at a possible model to explain dark matter. In this case, a perennial favorite known as primordial black holes. Black holes have long been proposed as the source of dark matter. In many ways, they are the perfect candidate because they only interact with light and matter gravitationally. But stellar-mass black holes have been ruled out observationally. There simply aren’t enough of them to account for dark matter.

December 14, 2021December 14, 2021 by Brian Koberlein

Forget That Planet That Orbits Every 16 Hours. That’s so Last Week. Now Astronomers Have Found a Metal Planet That Orbits its Star EVERY 8 HOURS

Artist view of a hot planet orbiting a red dwarf star. Credit: Patricia Klein

Most exoplanets are found using a technique known as the transit method, where the exoplanet passes in front of its star, causing the star to dim slightly. It takes several transits to confirm an exoplanet, so it’s not surprising that most known exoplanets have a fairly short orbital period. Months or days rather than years. There’s also an observational bias in that most known stars are red dwarfs, so it’s usually not surprising that we’ve found yet another exoplanet closely orbiting a red dwarf star. But sometimes what we find is so extreme, it really is surprising.

December 6, 2021December 6, 2021 by Brian Koberlein

Maybe “Boson Clouds” Could Explain Dark Matter

Coalsack Nebula and Kappa Crucis Cluster, photo: A. Fujii — The Jewel Box is shown just right of center, above the dark nebula called the Coal Sack in this picture of the southern sky. The picture was taken with a small ground-based camera.

The nature of dark matter continues to perplex astronomers. As the search for dark matter particles continues to turn up nothing, it’s tempting to throw out the dark matter model altogether, but indirect evidence for the stuff continues to be strong. So what is it? One team has an idea, and they’ve published the results of their first search.