Universe Today

December 19, 2023December 21, 2023 by Paul M. Sutter

Why String Theory Requires Extra Dimensions

String theory found its origins in an attempt to understand the nascent experiments revealing the strong nuclear force. Eventually another theory, one based on particles called quarks and force carriers called gluons, would supplant it, but in the deep mathematical bones of the young string theory physicists would find curious structures, half-glimpsed ghosts, that would point to something more. Something deeper.

December 18, 2023December 18, 2023 by Mark Thompson

Millions of Satellites Could Have a Profound Effect on the Earth’s Ionosphere

Mega-constellations of satellites. Credit: ESA-Science Office

Hardly a day goes by where a story hits the headlines about our abuse of the Earth’s precious environment be that the atmosphere or the oceans, forests or desert. When it comes to the atmosphere we all tend to immediately turn our attention to pollution, to gasses being released and disturbing the delicate balance. Yet a paper recently published points to a new demon, megaconstellations of satellites damaging the ionosphere – the ionised part of the upper atmosphere.

December 18, 2023December 18, 2023 by Paul M. Sutter

The Holographic Secret of Black Holes

This artist’s impression depicts a rapidly spinning supermassive black hole surrounded by an accretion disc. This thin disc of rotating material consists of the leftovers of a Sun-like star which was ripped apart by the tidal forces of the black hole. Shocks in the colliding debris as well as heat generated in accretion led to a burst of light, resembling a supernova explosion. Credit: ESO, ESA/Hubble, M. Kornmesser

As weird as it might sound, black holes appear to be holograms.

December 18, 2023December 18, 2023 by Evan Gough

Toxic Gas is Leaking out of Enceladus. It’s also a Building Block of Life.

The Cassini spacecraft captured this image of cryovolcanic plumes erupting from Enceladus' ice-capped ocean. Image Credit: NASA/JPL/CalTech

Enceladus’ status as a target in the search for life keeps rising. We’ve known for years that plumes erupting from the ocean under the moon’s icy shell contain important organic compounds related to life. Now, researchers have found another chemical in the plumes which is not only highly toxic but also critical in the appearance of life.

December 18, 2023December 18, 2023 by Andy Tomaswick

Astronomers Scan Hundreds of Stars for “Anomalous Transits”

Telescopes have been collecting copious amounts of data on exoplanets in recent years. One of the most common datasets tracks what are known as “transits,” where an exoplanet crosses in front of its host star and dims the star’s light slightly as it does so. The majority of exoplanets have been found this way, but other interesting details might be hidden in the data. For example, what would it mean if the transits happened in a way that disagreed with typical Newtonian physics? One answer to that question is that there might be an intelligent force behind the discrepancy – and that’s what a group of researchers at Breakthrough Listen began looking for in a paper recently published on arXiv.

December 16, 2023December 16, 2023 by Matt Williams

Scientists are Recommending IceCube Should be Eight Times Bigger

This image shows a visual representation of one of the highest-energy neutrino detections superimposed on a view of the IceCube Lab at the South Pole. Credit: IceCube Collaboration

The IceCube Neutrino Observatory, operated by the University of Wisconsin-Madison (UW-M), located at the Amundsen–Scott South Pole Station in Antarctica, is one of the most ambitious neutrino observatories in the world. Behind this observatory is the IceCube Collaboration, an international group of 300 physicists from 59 institutions in 14 countries. Relying on a cubic kilometer of ice to shield from external interference, this observatory is dedicated to the search for neutrinos. These nearly massless subatomic particles are among the most abundant in the Universe and constantly pass through normal matter.

By studying these particles, scientists hope to gain insight into some of the most violent astrophysical sources – such as supernovae, gamma-ray bursts, merging black holes and neutron stars, etc. The group of scientists tasked with advising the U.S. government on particle physics research is known as the Particle Physics Project Prioritization Panel (P5). In a recent draft report, “Pathways to Innovation and Discovery in Particle Physics,” the P5 team recommended a planned expansion of IceCube. This recommendation is one of several that define the future of astrophysics and particle physics research.

December 16, 2023December 16, 2023 by Brian Koberlein

Could There Be a Black Hole Inside the Sun?

It’s a classic tale of apocalyptic fiction. The Sun, our precious source of heat and light, collapses into a black hole. Or perhaps a stray black hole comes along and swallows it up. The End is Nigh! If a stellar-mass black hole swallowed our Sun, then we’d only have about 8 minutes before, as the kids say, it gets real. But suppose the Sun swallowed a small primordial black hole? Then things get interesting, and that’s definitely worth a paper on the arXiv.

December 15, 2023December 15, 2023 by Nancy Atkinson

Hubble Sees a Random Collection of Galaxies, Perfectly Lined Up

A pair of interacting galaxies, one smaller than the other. Each has a bright spot at the centre and two loosely-wound spiral arms, with threads of dark dust following the arms. They appear as a broad, soft glow in which individual stars can’t be seen. A number of bright stars and smaller, background galaxies can also be seen — three such galaxies lie in a vertical line below the right-hand galaxy of the pair.

This new image from the Hubble Space Telescope looks like a series of smaller spiral galaxies are falling out of a larger and brighter galaxy. That’s just one of the many reasons this collection of galaxies belongs to the Arp-Madore catalogue of peculiar galaxies.

December 15, 2023December 15, 2023 by Mark Thompson

Photonic Crystals Could Be Exactly What Breakthrough Starshot is Looking For

Could a solar-sail-like structure (or structures) tethered to an asteroid provide a sunshade for Earth to block sunlight and mitigate climate change? A recent study looks into it. Courtesy NASA.

Light sail technology is a fascinating concept and a step change in rocket propulsion. It may not be big and impressive like the Saturn V, the Space Shuttle or the new Starship rocket but when it comes to travelling among the stars, light sails could just be the answer. And what better material to build the sails from then something that just makes me want to say it over and over again….I talk about photonics crystals. It’s sounds right out of a Star Trek episode but a new paper examines their feasibility.

December 15, 2023December 16, 2023 by Evan Gough

17 Known Exoplanets Could Have Oceans of Liquid Water

Astrobiologists believe that the Solar System's ice worlds are some of the most interesting places to search for life. These are moons or dwarf planets with thick ice shells surrounding oceans of liquid water - the perfect habitats for life. A new NASA study has found 17 exoplanets that have the right size, density and distance from their stars, and are probably similar to Europa or Enceladus and might even have geysers blasting water into space. Image Credit: NASA

The search for life is tied to the search for liquid water. That’s why astronomers are so keen on detecting rocky, Earth-like exoplanets in their stars’ habitable zones. In a habitable zone, a planet receives enough energy from its star to maintain liquid water on its surface, given the right atmospheric conditions.

But in our Solar System, we’ve found worlds with liquid water that are way beyond the habitable zone. Can we do the same in other solar systems?