Universe Today

September 14, 2023September 14, 2023 by Nancy Atkinson

The Seasons on Saturn are Changing. It's Time to Say Goodbye to Its North Pole for a Few Years

Saturn, as seen by the James Webb Space Telescope's MIRI instrument, showing various portions of the planet's atmosphere. superimposed on an full image taken by the Hubble Space Telescope. Credit: NASA/ESA/Univ. Leicester/L.N. Fletcher/O. King

Just like Earth, Saturn goes through seasons because of its axial tilt. But a year on Saturn lasts 30 Earth years, so each of its seasons lasts 7.5 years. Right now, it is late summer on Saturn’s northern hemisphere, so again, just like Earth is currently heading for northern autumn equinox in September, Saturn is heading for northern autumn equinox a little later, in 2025.

Before Saturn’s north pole enters its extended polar winter – rendering it inaccessible for observations — astronomers are taking advantage of being able to study this area with the James Webb Space Telescope, which became operational just over a year ago.

September 14, 2023September 17, 2023 by Matt Williams

Some Lunar Regolith is Better for Living Off the Land on the Moon

Artist's impression of astronauts on the lunar surface, as part of the Artemis Program. Credit: NASA

Between now and the mid-2030s, multiple space agencies hope to send crewed missions to the Moon. of These plans all involve establishing bases around the Moon’s southern polar region, including the Artemis Base Camp and the International Lunar Research Station (ILRS). These facilities will enable a “sustained program of lunar exploration and development,” according to the NASA Artemis Program mission statement. In all cases, plans for building facilities on the surface call for a process known as In-Situ Resource Utilization (ISRU), where local resources are used as building materials.

This presents a bit of a problem since not all lunar soil (regolith) is well-suited for construction. Much like engineering and construction projects here on Earth, builders need to know what type of soil they are building on and if it can be used to make concrete. In a recent study, planetary scientist Kevin M. Cannon proposed a lunar soil classification scheme for space resource utilization. This could have significant implications for future missions to the Moon, where it would help inform the construction of bases, habitats, and other facilities based on soil type and location.

September 14, 2023September 14, 2023 by Laurence Tognetti

Planning is Underway for NASA’s Next Big Flagship Space Telescope

Artist rendition of a starshade being used on a future space telescope. This example shows the proposed Habitable Exoplanet Observatory (HabEx), which the 2020 Astrophysics Decadal Survey decided to combine elements of this with the Large Ultraviolet Optical Infrared Surveyor (LUVOIR) for a new flagship telescope, which is now known as the Habitable Worlds Observatory (HWO). (Credit: NASA)

NASA’s James Webb Space Telescope (JWST) has only been operational for just over a year, but this isn’t stopping the world’s biggest space agency from discussing the next big space telescope that could serve as JWST’s successor sometime in the future. Enter the Habitable Worlds Observatory (HWO), which was first proposed as NASA’s next flagship Astrophysics mission during the National Academy of Sciences’ Decadal Survey on Astronomy and Astrophysics 2020 (Astro2020). While its potential technological capabilities include studying exoplanets, stars, galaxies, and a myriad of other celestial objects for life beyond Earth, there’s a long way to go before HWO will be wowing both scientists and the public with breathtaking images and new datasets.

September 13, 2023September 13, 2023 by Carolyn Collins Petersen

Quasars Have Always Had Dark Matter Halos

Illustration of an active quasar. What role does its dark matter halo play in activating the quasar? Credit: ESO/M. Kornmesser — Illustration of an active quasar. New research shows that SMBHs eat rapidly enough to trigger them. Credit: ESO/M. Kornmesser

When you look at most galaxies in the Universe, you’re looking at the homes of supermassive black holes. It now appears that quasars, which are active galaxies spitting out huge amounts of radiation from the region around their black holes, also have massive dark matter halos. It turns out they’ve always had them. And, their black hole activity has a direct connection with those halos.

September 13, 2023September 13, 2023 by Evan Gough

Could We Find Aliens Terraforming Other Worlds?

Artist's conception of a terraformed Mars. Credit: Ittiz/Wikimedia Commons

The first early humans to use fire had no inkling of what it would lead to.

Fire was one of our first technologies, and humans have been making changes to their environments since the advent of controlled fire hundreds of thousands of years ago. Fast forward to current times, and our modern technological and global civilization is changing the Earth’s entire biosphere. From carbon emissions that acidify the oceans and weaken the shells of marine life to microplastics that find their way into organisms’ bloodstreams, our technology is intersecting, or combining, with the biosphere.

This has spawned a useful word: biotechnosphere.

September 13, 2023September 13, 2023 by Matt Williams

Whether Saturn's Rings are Young or Old, its Moons are as Ancient as the Planet Itself

The moons of Saturn, from left to right: Mimas, Enceladus, Tethys, Dione, Rhea; Titan in the background; Iapetus (top) and irregularly shaped Hyperion (bottom). Some small moons are also shown. All to scale. Credit: NASA/JPL/Space Science Institute

Saturn is best known for two things: its iconic ring structures and its large system of natural satellites. Currently, 146 moons and moonlets have been discovered orbiting the ringed giant, 24 of which are regular satellites. These include the seven largest moons, Titan, Rhea, Iapetus, Dione, Tethys, Enceladus, and Mimas, which are icy bodies believed to have interior oceans. In addition, there are unresolved questions about the age of these satellites, with some suspecting that they formed more recently (like Saturn’s rings, which are a few hundred million years old).

To address these questions, an international team of astronomers created a series of high-resolution simulations coupled with improved estimates of Trans-Neptunian Object (TNO) populations. This allowed them to construct a chronology of impacts for Saturn’s most heavily cratered regular satellites – Mimas, Enceladus, Tethys, Dione, and Rhea. This established age limits of 4.1 and 4.4 billion years for all five, with the two innermost moons appearing more youthful than the outer three. These results could have significant implications for our understanding of the formation and tidal evolution of moons in the outer Solar System.

September 13, 2023September 13, 2023 by Brian Koberlein

Has the First Biosignature Been Found on an Exoplanet?

Artist's impression of Earth in the early Archean with a purplish hydrosphere and coastal regions. Even in this early period, life flourished and was gaining complexity. Credit: Oleg Kuznetsov — Artist's impression of Earth in the early Archean with a purplish hydrosphere and coastal regions. Even in this early period, life flourished and was gaining complexity, and distant exoplanets might begin similarly. Credit: Oleg Kuznetsov

Recently I wrote about the discovery of a hycean world. A potentially habitable exoplanet with a deep warm ocean and thick, hydrogen-rich atmosphere. Such planets are thought to be somewhat common orbiting red dwarf stars, and they are an excellent candidate for life. While it’s an exciting discovery, buried in the research article was something even more exciting. Tentative evidence of a biosignature, hinting at the presence of life. You can guess which discovery started making headlines. But have astronomers really found life on another planet?

September 12, 2023September 13, 2023 by Carolyn Collins Petersen

Astronomers Observe Blobs of Dark Matter Down to a Scale of 30,000 Light-Years Across

Dark matter fluctuations in the lens system MG J0414+0534. The whitish blue color represents the gravitationally lensed images observed by ALMA. The calculated distribution of dark matter is shown in orange; brighter regions indicate higher concentrations of dark matter and dark orange regions indicate lower concentrations. (Credit: ALMA (ESO/NAOJ/NRAO), K. T. Inoue et al.?

Dark matter remains mysterious and… well… dark. While we don’t yet have a definite idea of what this cosmic “stuff” is made of, astronomers are learning more about its distribution throughout the Universe. Since we can’t see it directly, observers need to use indirect methods to detect it. One way is through gravitational lensing. Another is by looking for emissions from hydrogen gas associated with small-scale dark matter structures in the Universe.

September 12, 2023September 12, 2023 by Evan Gough

Lucy Has its First Asteroid Target in the Crosshairs

This image shows the tiny main-belt asteroid Dinkinesh. Lucy captured this image from 23 million km away. Image Credit: NASA/Goddard/SwRI/Johns Hopkins APL

NASA’s Lucy spacecraft launched almost one year ago, in October of 2021. Its journey is an ambitious one, and long. It’ll visit eight different asteroids in its planned 12-year mission. Two of them are main belt asteroids, and the other six are Jupiter Trojans, which share the gas giant’s orbit around the Sun.

Lucy’s first, and smallest, target asteroid is now in the spacecraft’s sights.

September 12, 2023September 12, 2023 by Evan Gough

The Hubble Imaged Some Globular Clusters in an Unusual Place: Near the Milky Way’s Centre

Most globular clusters are found in the Milky Way's halo. But some, like the glittering globular cluster Terzan 12, are near the galactic centre. Image Credit: ESA/Hubble & NASA, R. Cohen (Rutgers University)

Our galaxy has about 200 Globular Clusters (GCs,) and most of them are in the galaxy’s halo. Astronomers think most GCs were taken from dwarf galaxies and merged with the Milky Way due to the galaxy’s powerful gravity. That explains why so many of them are on the outskirts of the galaxy. But they’re not all in the halo. Some are towards the Milky Way’s galactic bulge. What are globular clusters doing there?