Universe Today

December 13, 2023December 13, 2023 by Andy Tomaswick

JWST Finds the Smallest Free-Floating Brown Dwarf

Star cluster IC 348 seen by the MIRI instrument of JWST. Image credit: NASA, ESA, CSA, STScI, Kevin Luhman (PSU), Catarina Alves de Oliveira (ESA). Brown dwarf image credit: NASA

Star formation is happening all around us in the Universe. However, there is still plenty we don’t know about it, including, as a recent press release points out, something that every astronomy textbook points out – we don’t know the size of the smallest star. Most current answers in those textbooks refer to an object known as a brown dwarf, a cross between a star and a giant planet. Recently, the James Webb Space Telescope (JWST) found what is believed to be the smallest brown dwarf ever discovered – and it weighs in at only 3-4 times the weight of Jupiter.

December 12, 2023December 12, 2023 by Mark Thompson

Planets Orbiting Pulsars Should Have Strange and Beautiful Auroras. And We Could Detect Them

Artist's impression of auroras on a planet orbiting a pulsar

We have been treated to some amazing aurora displays over recent months. The enigmatic lights are caused by charged particles from the Sun rushing across space and on arrival, causing the gas in the atmosphere to glow. Now researchers believe that even on exoplanets around pulsars we may just find aurora, and they may even be detectable.

December 12, 2023December 12, 2023 by Carolyn Collins Petersen

How Do Superflares Get So Powerful?

We live with a star that sends out flares powerful enough to disrupt things here on Earth. Telecommunications, power grids, even life itself, are affected by strong solar activity. But, the Sun’s testy outbursts are almost nothing compared to the superflares emitted by other stars. Why do flares happen? And what’s going on at distant stars to ramp up the power of their flares?

December 12, 2023December 12, 2023 by Mark Thompson

Solar Storms Could Cause Mayhem to Trains

The rail service here in the UK is often the brunt of jokes. If it’s not the wrong type of rain, or the leaves are laying on the tracks the wrong way then it’s some other seemingly ludicrous reason that the trains are delayed, or even cancelled. A recent study by scientists at the University of Lancaster suggest that even the solar wind might cause train signals to be incorrectly triggered with potentially disastrous consequences.

December 12, 2023December 13, 2023 by Matt Williams

We've Entered a New Era: The Lunar Anthropocene

Humans on the Moon. Image credit: Envato Elements

For almost half a century, the term “Anthropocene” has been informally used to describe the current geological epoch. The term acknowledges how human agency has become the most significant factor when it comes to changes in Earth’s geology, landscape, ecosystems, and climate. According to a new study by a team of geologists and anthropologists, this same term should be extended to the Moon in recognition of humanity’s exploration (starting in the mid-20th century) and the growing impact our activities will have on the Moon’s geology and the landscape in the near future.

December 12, 2023December 12, 2023 by Andy Tomaswick

The Positions of Stars on an Ancient Navigation Device Tell us When it was Made

Astrolabes serve two purposes. First, they are useful as an astronomical tool, especially for finding a ship’s latitude. But second, they are works of art in themselves. Besides having to be precise, many are beautiful. They are even seeing a resurgence in popularity as collectors lap up even those made by modern manufacturing processes because of their aesthetic appeal. Now, a new paper adds to their uses – a self-referential ability to mark what year they were made by the patterns of the stars they reference.

December 12, 2023December 13, 2023 by Nancy Atkinson

Review: Unistellar’s eQuinox 2 Telescope and New Smart Solar Filter

The Sun on November 27, 2023, observed using the Unistellar eQuinox 2 and the new smart solar filter. Credit: Nancy Atkinson and Unistellar.

I recently had the chance to try out one of Unistellar’s smart telescopes, the eQuinox 2. Unparalleled in its ease of use, I was literally viewing distant nebula, galaxies, and star clusters within 15 minutes of opening the box.

I also had the opportunity to try out Unistellar’s new Smart Solar Filter, which I’ll discuss more below. But first, more about the telescope itself:

December 12, 2023December 12, 2023 by Carolyn Collins Petersen

Three Baby Stars Found at the Heart of the Milky Way

The image, taken with ESO's Very Large Telescope in Chile, shows a high-resolution view of the innermost parts of the Milky Way. In the new study, the researchers examined the dense nuclear star cluster shown in detail here. Credit: ESO. Milky Way in the background. Image credit: NASA

The core of our Milky Way is buzzing with stars. Recently astronomers reported that it contains at least one ancient star that formed outside our galaxy. Now, an international research team reports finding a grouping of very young ones there, as well. Their presence upends ideas about star birth in that densely packed region of space.

December 11, 2023December 11, 2023 by Evan Gough

Exomoons Defy Discovery

So far we only know of two exoplanets with candidate exomoons. But even those two may be false positives. Image Credit: NASA

For a long time, we wondered if other stars hosted planets like the Sun does. Finally, in the 1990s, we got our answer. Now, another question lingers.

Most of the planets in our Solar System have moons. Do exoplanets have exomoons?

December 11, 2023December 14, 2023 by Matt Williams

Why Was it Tricky to Know the Distances to Galaxies JWST Was Seeing?

Obtaining accurate redshift measurements is a challenge, even with telescopes like Webb. Credit: NASA

One of the chief objectives of the James Webb Space Telescope (JWST) is to study the formation and evolution of the earliest galaxies in the Universe, which emerged more than 13 billion years ago. To this end, scientists must identify galaxies from different cosmological epochs to explore how their properties have changed over time. This, in turn, requires precise dating techniques so astronomers are able to determine when (in the history of the Universe) an observed galaxy existed. The key is to measure the object’s redshift, which indicates how long its light has been traveling through space.

This is the purpose of the Cosmic Evolution Early Release Science Survey (CEERS), a collaborative research group that analyzes Webb data to learn more about galactic evolution. These galaxies are known as “high-redshift,” meaning that their light emissions are redshifted all the way into the infrared spectrum. Galaxies that existed ca. 13 billion years ago can only be observed in the near-infrared spectrum, which is now possible thanks to Webb’s Near-Infrared Camera (NIRCam). Even so, obtaining accurate redshift measurements from such distant galaxies is a very tricky, and requires advanced techniques.