Brian Koberlein, Author at Universe Today

August 16, 2023August 16, 2023 by Brian Koberlein

New Horizons is So Far Away, it Can Measure the True Darkness of the Universe

Artist view of the New Horizons spacecraft against a sea of stars. Credit: Serge Brunier/Marc Postman/Dan Durda

Just how dark is the night sky?

If you step outside during a moonless night and look up, it probably doesn’t look that dark at all. Streetlights or nearby porch lights fill the air with a background glow, particularly if they happen to be bluish-white LEDs. Light pollution in your neighborhood is likely so bad that you can only see a few bright stars. Even in somewhat rural areas, our skies are so bright that the Milky Way isn’t really visible. In North America and Europe, only about a quarter of children have seen the Milky Way.

August 14, 2023August 14, 2023 by Brian Koberlein

Storms on Saturn Can Have Impacts That Last for Hundreds of Years

A giant storm rages on Saturn. Credit: NASA/JPL-Caltech/SSI

The Great Red Spot of Jupiter is a storm that has raged for hundreds of years. It was first observed by Gian Domenico Cassini in 1665, and except for a period between 1713 to 1830, it has been observed continuously ever since. Even if Cassini’s storm is not the one we see today, the current red spot has been around for nearly two centuries. While great storms appear now and then on Saturn and other gas planets, they don’t have the staying power of Jupiter’s great storm. Or so we thought.

August 13, 2023August 13, 2023 by Brian Koberlein

Vera Rubin Will Find Many More Interstellar Objects

Illustration of an interstellar object approaching our solar system. Credit: Rubin Observatory/NOIRLab/NSF/AURA/J. daSilva

Most of the comets we see in the sky were born in our solar system. They may have formed deep within the Oort cloud, and for some, it is their first visit to the inner solar system, but they are distinctly children of the Sun. We know of only two objects that came from beyond our solar system, Omuamua and Borisov. There are likely other interstellar objects visiting our solar system, we just haven’t found them. But that’s likely to change when Rubin Observatory comes online.

August 12, 2023August 12, 2023 by Brian Koberlein

Giant Tidal Waves are Crashing Onto the Surface of an Enormous Star

Illustration of waves breaking on a heartbeat star. Credit: Melissa Weiss, CfA

Binary star systems often appear as variable stars. When we can’t see the individual stars because they are either too close together or too far away, we can see the gradual brightening and dimming of a single point of light as the stars orbit each other. Sometimes if the stars are particularly close when they pass each other they can brighten in unusual ways. One example of this is known as a heartbeat star.

August 11, 2023August 11, 2023 by Brian Koberlein

Evidence for Modified Gravity Found in the Motions of Binary Stars

Artistic repesentation of a binary star system. Credit: NASA/JPL-Caltech

With our continued failure to discover dark matter particles, it’s worth considering alternatives. While dark matter is the most widely supported model, the alternatives fall into two broad paths. One is that we should look to extended models of general relativity, such as conformal gravity. The other argues we should modify the very nature of Newtonian dynamics. The first approach tends to be popular with theorists since it focuses on an abstract theory in the same vein as Einstein’s original ideas. The second, often known as Modified Newtonian Dynamics, or MoND, tends to be more popular with observational astronomers.

August 10, 2023August 10, 2023 by Brian Koberlein

Astronomers Search for Dark Matter Annihilation at the Center of the Earth

How IceCube can detect neutrinos from Earth's core. Credit: IceCube Collaboration

Dark matter is one of the thorniest mysteries of modern cosmology. On the one hand, astronomers have gathered a wealth of supporting evidence through galaxy clustering statistics, gravitational lensing, and cosmic microwave background fluctuations, on the other hand, there are no particles in the standard model of particle physics that could account for dark matter, and we haven’t been able to detect its effect locally. It’s a solid theory where we just can’t seem to fully pin it down. That usually means we’re just a breakthrough away from confirming or overthrowing dark matter. The good news is that there are several projects searching for dark matter, and one of them, the IceCube Neutrino Observatory, has just released a new result.

August 9, 2023August 9, 2023 by Brian Koberlein

Could This Supermassive Black Hole Only Have Formed by Direct Collapse?

Artist's impression of an active supermassive black hole in the early universe. Credit: NOIRLab/NSF/AURA/J. da Silva

Nearly every galaxy in the universe contains a supermassive black hole. Even galaxies that are billions of light years away. This means supermassive black holes form early in the development of a galaxy. They are possibly even the gravitational seeds around which a galaxy forms. But astronomers are still unclear about just how these massive gravitational beasts first appeared.

August 8, 2023August 8, 2023 by Brian Koberlein

Mars is Spinning Faster and Faster

Artistic rendering of the InSight lander. Credit: NASA/InSight

A day on Earth last about 24 hours. The word “about” in that sentence does a lot of heavy lifting because Earth’s rate of rotation changes all the time. Not by much, only fractions of milliseconds, but it means our common 24-hour day only really applies at human scales.

There are several things that can change the Earth’s rotation. The gravitational tug of the Moon and tides are gradually slowing Earth over millions of years. The melting of ice in the polar regions, the tectonic shift of the Earth’s crust during earthquakes, and even the draining of water from the aquifer. Earth is a geologically and biologically active world, so it’s only natural that Earth’s rotation rate is also dynamic. But a recent study shows that the rotation of Mars is also changing, which is a bit of a surprise.

August 6, 2023August 6, 2023 by Brian Koberlein

Some Metal Meteorites Have a Tiny Magnetic Field. But How?

Illustration of the metallic asteroid Psyche. Credit: Peter Rubin/NASA/JPL-Caltech/ASU

One of the striking things about iron meteorites is that they are often magnetic. The magnetism isn’t strong, but it holds information about their origin. This is why astronomers discourage meteorite hunters from using magnets to distinguish meteorites from the surrounding rock, since hand magnets can erase the magnetic history of a meteorite, which is an important scientific record.

August 5, 2023August 5, 2023 by Brian Koberlein

Do Technological Civilizations Depend on Atmospheric Oxygen?

Humans gathered around an evening campfire. Credit: Jarek Tuszy?ski / CC-BY-SA-3.0 & GDFL

Nearly two million years ago a species of upright apes known as homo erectus began to utilize fire. It was a gradual process, from opportunistic users of natural fires to masters able to craft flames from flint and tender. We are their descendants. We are creatures of forge and kiln, hearth and home. Fire has become so central to us that instead of homo sapiens, we could call ourselves homo ignus, the fire-wielding ape. Fire is central to the rise of our civilization. It cooks our food, keeps us warm, and illuminates our night. This raises an interesting question. Could we have built a civilization without fire?