Brian Koberlein, Author at Universe Today

August 4, 2020 by Brian Koberlein

The Universe is the Same, Everywhere We Look. Even More than Cosmologists Predicted

Several superclusters revealed by the 2dF Galaxy Redshift Survey. This contains the structure known as the "Sloan Great Wall". Courtesy 2dF Galaxy Redshift Survey.

No matter which direction you look in the Universe, the view is basically the same if you look far enough. Our local neighborhood is populated with bright nebulae, star clusters, and dark clouds of gas and dust. There are more stars toward the center of the Milky Way than there are in other directions. But across millions, and billions, of light-years, galaxies cluster evenly in all directions, and everything starts to look the same. In astronomy, we say the Universe is homogeneous and isotropic. Put another way, the Universe is smooth.

August 3, 2020 by Brian Koberlein

How Loop Quantum Gravity Could Match Anomalies in the CMB with Large Structures in the Modern Universe

Map of the cosmic microwave background (CMB) sky produced by the Planck satellite. The Cold Spot is shown in the inset, with coordinates and the temperature difference in the scale at the bottom. Credit: ESA/Durham University.

Our universe is best described by the LCDM model. That is an expanding universe filled with dark energy (Lambda), and dense clumps of cold dark matter (CDM). It is also sprinkled with regular matter that makes up planets, stars, and us, but that only makes up about 4% of the cosmos. While we don’t know what dark matter and dark energy are, we know how they behave, so the ?CDM model works exceptionally well. There’s just one small problem.

July 29, 2020July 29, 2020 by Brian Koberlein

There Might Be an Entire Orbit, Filled with Asteroids that Came from Outside the Solar System

An illustration of the orbit of a Centaur asteroid. Credit: Namouni and Morais, NASA

Aliens could be all around us. Lurking on the edge, waiting to invade our solar system. Not little green creatures, but asteroids from other stars. That’s the conclusion of a new study published in the Monthly Notices of the Royal Astronomical Society.

July 27, 2020July 28, 2020 by Brian Koberlein

Gamma-Ray Telescopes Can Measure the Diameters of Other Stars

The VERITAS array, an air Cherenkov telescope designed to detect low-energy cosmic rays. Credit: VERITAS

In astronomy, the sharpness of your image depends upon the size of your telescope. When Galileo and others began to view the heavens with telescopes centuries ago, it changed our understanding of the cosmos. Objects such as planets, seen as points of light with the naked eye, could now be seen as orbs with surface features. But even under these early telescopes, stars still appeared as a point of light. While Galileo could see Jupiter or Saturn’s size, he had no way to know the size of a star.

July 22, 2020July 22, 2020 by Brian Koberlein

A Black Hole Popping Out of a Traversable Wormhole Should Give Off a Very Specific Signal in Gravitational Waves

Artist view of colliding neutron stars. Credit: ESO/L. Calçada/M. Kornmesser

Gravitational wave astronomy has changed the way we view the cosmos. In only a few years we have observed the collisions of black holes and neutron stars, confirming our theoretical understanding of these strange objects. But as gravitational wave astronomy matures, it will allow us to probe the very nature of space and time itself. While that day is a long way off, it hasn’t stopped the theory folks from dreaming up new discoveries. For example, how it might look if a black hole and a wormhole interact.

July 20, 2020July 20, 2020 by Brian Koberlein

What Shuts Down a Galaxy’s Star Formation?

Artist impression of 14 galaxies detected by ALMA as they appear in the very early, very distant universe. These galaxies are in the process of merging and will eventually form the core of a massive galaxy cluster. Credit: NRAO/AUI/NSF; S. Dagnello

In the 1920s, Edwin Hubble studied hundreds of galaxies. He found that they tended to fall into a few broad types. Some contained elegant spirals of bright stars, while others were spherical or elliptical with little or no internal structure. In 1926 he developed a classification scheme for galaxies, now known as Hubble’s Tuning Fork.

Hubble’s tuning fork diagram for galaxies. Credit: Edwin Hubble

When you look at Hubble’s scheme, it suggests an evolution of galaxies, beginning as an elliptical galaxy, then flattening and shifting into a spiral galaxy. While many saw this as a reasonable model, Hubble cautioned against jumping to conclusions. We now know ellipticals do not evolve into spirals, and the evolution of galaxies is complex. But Hubble’s scheme marks the beginning of the attempt to understand how galaxies grow, live, and die.

July 14, 2020July 14, 2020 by Brian Koberlein

Stars Like Our Sun Become Lithium Factories as They Die

This artist’s impression shows the red supergiant star. Using ESO’s Very Large Telescope Interferometer, an international team of astronomers have constructed the most detailed image ever of this, or any star other than the Sun. Credit: ESO/M. Kornmesser

In the beginning, the big bang created three elements: hydrogen, helium, and lithium. But it only produced a trace of lithium. For every lithium atom created, the big bang produced about 10 billion hydrogen atoms, and 3 billion helium atoms. The ratio of primordial elements is one of the triumphs of the big bang model. It predicts the ratio of hydrogen (H) and helium (⁴He) perfectly, and even works for the ratios of other isotopes, such as deuterium (²H) and helium-3 (³He). But it doesn’t work for lithium, and we aren’t sure why.

July 10, 2020July 10, 2020 by Brian Koberlein

Earth’s Magnetic Field is Changing Surprisingly Quickly

Visual simulation of the Earth's magnetic field. Credit: NASA Goddard Space Flight Center

If you’ve ever used a compass, you know that the magnetic needle always points North. Well, almost North. If you just happen to be out camping for the weekend, the difference doesn’t matter. For scientists studying the Earth’s interior, the difference is important. How Earth’s magnetic field changes over time give us clues about how our planet generates a magnetic field in the first place.

July 7, 2020July 7, 2020 by Brian Koberlein

Amateur Astronomers Find a Brand New Storm on Jupiter

JunoCam took this image during its eleventh close flyby of Jupiter on February 7, 2018. Image credit: NASA / JPL / SwRI / MSSS / David Marriott.

There’s a new storm brewing on Jupiter. The most famous storm on Jupiter is the Great Red Spot, which has been active since at least the time of Galileo. Most of Jupiter’s storms don’t last for hundreds of years. They grow and fade just as they do on Earth. This latest storm was discovered by amateur astronomer Clyde Foster.

July 3, 2020July 3, 2020 by Brian Koberlein

Astronomers Might Have Seen a Star Just Disappear. Turning Straight to a Black Hole Without a Supernova

This illustration shows what the luminous blue variable star in the Kinman Dwarf galaxy could have looked like before its mysterious disappearance. Credit: ESO/L. Calçada

Large stars have violent deaths. As they run out of hydrogen to fuse, the star’s weight squeezes its core to make it increasingly hot and dense. The star fuses heavier elements in a last-ditch effort to keep from collapsing. Carbon to Silicon to Iron, each step generating heat and pressure. But soon it’s not enough. The fusion even heavier elements don’t give the star more energy, and the core quickly collapses. The protons and neutrons of nuclei collide so violently that the resulting shock wave rips the star about. The outer layers of the star are thrown outward, becoming a brilliant supernova. For a brief time, the star shines brighter than its entire galaxy, and its core collapses into a neutron star or black hole. It was thought that all large stars end with a supernova, but new research finds that might not be the case.