Universe Today

January 3, 2024January 3, 2024 by Scott Alan Johnston

Iron Snow Could Explain the Magnetic Fields at Worlds Like Ganymede

Iron snow in the core of Ganymede. Credits: Image by Ludovic Huguet and map texture from NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Jupiter’s largest moon, Ganymede, features a surprisingly strong magnetic field for its size. Tidal effects from Jupiter continually stretch and squeeze the moon, keeping its core warm and driving the magnetic field. But the exact geological processes occurring within the core are not fully understood. Now, a new experimental study has put one of the leading models of core dynamics to the test: the formation of crystalized ‘iron snow’.

January 3, 2024January 3, 2024 by Mark Thompson

China’s FAST Observatory is Playing a Key Role in the Search for Aliens

Some years ago I rememeber running the SETI at Home screensaver and would watch it for hours to see if any peaks appeared naively thinking they might be signals from an alien civilisation! There is no doubt that the search for extraterrestrials (ET) has captivated the minds of many people across the years. The search has of course to date, been unsuccesful despite multiple observations that seem to suggest the conditions for life across the cosmos may actually be more common than we first thought. Now Chinese agencies are funding projects to use the Five Hundred Meter Aperture Spherical Telescope (FAST) to conduct searches for alien signals.

January 3, 2024January 3, 2024 by Evan Gough

Ingenuity’s 69th Flight is its Farthest So Far

Ingenuity captured this image of Mars on December 2nd 2023 (Sol 990) with its high-resolution colour camera. Image Credit: NASA/JPL-Caltech

When NASA decided to send the little Ingenuity rotorcraft to Mars on the belly of the Perseverance rover, they weren’t certain of success. Nothing like it had ever been attempted in Mars’ extremely thin atmosphere. Mission planners hoped and planned for a total of five flights, enough for a technology demonstration.

But now, as almost everyone knows, Ingenuity has wildly exceeded NASA’s initial expectations.

January 3, 2024January 3, 2024 by Evan Gough

Juno Makes its Closest Flyby of Io

NASA's Juno spacecraft captured this image of Jupiter's volcanic moon Io. Image Credit: NASA / JPL-Caltech / SwRI / MSSS / Kevin Gill

NASA’s Juno spacecraft has been getting closer and closer to Jupiter’s volcanic moon Io with each recent orbit. Juno is in its 57th orbit of Jupiter, and on December 30th, Juno came to within 1500 km (930 miles) of Io’s surface. It’s been more than 20 years since a spacecraft came this close.

January 3, 2024January 3, 2024 by Evan Gough

The Oldest Known Spiral Galaxy Has Ripples Like the Surface of a Pond

This simulation illustrates a galaxy disk being disturbed, leading to the propagation of a seismic ripple throughout the disk. (Credit: Bland-Hawthorn and Tepper-Garcia, University of Sydney).

Astronomers have detected pond-like ripples across the gaseous disk of an ancient galaxy. What caused the ripples, and what do they tell us about the distant galaxy’s formation and evolution? And whatever happened, how has it affected the galaxy and its main job: forming stars?

January 3, 2024January 3, 2024 by Brian Koberlein

The Most Massive Neutron Stars Probably Have Cores of Quark Matter

Illustration of a quark core in a neutron star. Credit: Jyrki Hokkanen, CSC - IT Center for Science

Atoms are made of three things: protons, neutrons, and electrons. Electrons are a type of fundamental particle, but protons and neutrons are composite particles made of up and down quarks. Protons have 2 ups and 1 down, while neutrons have 2 downs and 1 up. Because of the curious nature of the strong force, these quarks are always bound to each other, so they can never be truly free particles like electrons, at least in the vacuum of empty space. But a new study in Nature Communications finds that they can liberate themselves within the hearts of neutron stars.

January 3, 2024January 3, 2024 by Nancy Atkinson

Watch a Full Martian Day, From Dawn to Dusk

Curiosity’s rear Hazcam captured the shadow of the back of the rover in this 12-hour view looking toward the floor of Gale Crater. A variety of factors caused several image artifacts, including a black speck, the distorted appearance of the Sun, and the rows of white pixels that streak out from the Sun. NASA/JPL-Caltech

On November 8th, NASA’s Curiosity Rover paused its incessant science work and just watched the day unfold on Mars. The rover used its black-and-white Hazard-Avoidance Cameras (Hazcams) to watch an entire 12-hour day on Mars as the shifting Sun cast shadows across the Martian landscape. NASA chose this day because of the Mars solar conjunction when the Sun interferes with communications with the Red Planet, meaning the rover doesn’t do any roving about. The timelapse comprises 25 frames from both the front and rear Hazcams.

January 2, 2024January 3, 2024 by Matt Williams

After all of This Time Searching for Aliens, is it The Zoo Hypothesis or Nothing?

The Karl Jansky Very Large Array at night, with the Milky Way visible in the sky. Credit: NRAO/AUI/NSF; J. Hellerman

In 1950, during a lunchtime conversation with colleagues at the Los Alamos National Laboratory, famed physicist Enrico Fermi asked the question that launched a hundred (or more) proposed resolutions. “Where is Everybody?” In short, given the age of the Universe (13.8 billion years), the fact that the Solar System has only existed for the past 4.5 billion years, and the fact that the ingredients for life are everywhere in abundance, why haven’t we found evidence of extraterrestrial intelligence by now? This came to be the basis of Fermi’s Paradox, which remains unresolved to this day.

Interest in Fermi’s question has been piqued in recent years thanks to the sheer number of “potentially habitable” exoplanets discovered in distant star systems. Despite that, all attempts to find signs of technological activity (“technosignatures”) have come up empty. In a recent study, a team of astrobiologists considered the possible resolutions and concluded that only two possibilities exist. Either extraterrestrial civilizations (ETCs) are incredibly rare (or non-existent), or they are deliberately avoiding contact with us (aka. the “Zoo Hypothesis“).

January 2, 2024January 2, 2024 by Mark Thompson

An Ancient Stone Found in Italy is an Accurate Map of the Night Sky

Digital elevation model of the frontal face of Rupinpiccolo stone disk from an adaptation of fig. 1 of Bernardini et al. (2022). The orientation is arbitrary

You know how some constellations take a little bit of imagination to see? Yes, Leo looks a bit like a lion and Orino a bit like a hunter but then we drift into the realms of powerful levels of imagination to be able to see Pegasus as a flying horse or Telescopium as a telescope! Even squinting or tilting your head really doesn’t make them visible. I found the same problem when looking at images of two stone disks discovered in Italy recently at the entrance to an ancient fort! Teams that have examined the stones have matched the subtle markings on them to positions of 28 bright stars in the sky! I had to really look to see it but I think they might actually be right!

January 2, 2024January 2, 2024 by Mark Thompson

The Sun Just Blasted its Strongest Flare in 6 Years. Get Ready for Auroras

While many of us were celebrating the end of 2023 and the coming of 2024, the Sun was having its own celebration blasting an X5.0 flare from sunspot region 3536. Records show this to be the most powerful flare seen since 10 September 2017 when an X8.2 flare erupted. The flare is expected to arrive around Jan 2 – EEK that’s today! Get your aurora watching kit out!