Universe Today

January 2, 2025January 2, 2025 by Matt Williams

NASA Scientists Discover “Dark Comets” Come in Two Populations.

An artist's concept of a dark comet floating in space. Courtesy Nicole Smith.

On October 19th, 2017, the Panoramic Survey Telescope and Rapid Response System-1 (Pan-STARRS-1) in Hawaii announced the first-ever detection of an interstellar object, named 1I/2017 U1 ‘Oumuamua (the Hawaiin word for “scout”). This object created no shortage of confusion since it appeared as an asteroid but behaved like a comet (based on the way it accelerated out of the Solar System). Since then, scientists have noticed a lot of other objects that behave the same way, known as “dark comets.”

These objects are defined as “small bodies with no detected coma that have significant nongravitational accelerations explainable by outgassing of volatiles,” much like ‘Oumuamua. In a recent NASA-supported study, a team of researchers identified seven more of these objects in the Solar System, doubling the number of known dark comets. Even more important, the researchers were able to discern two distinct populations. They consist of larger objects that reside in the outer Solar System and smaller ones in the inner Solar System.

January 2, 2025January 2, 2025 by Mark Thompson

Could There Be Bacteria Living on Mars Today?

Methanogens. Credit: Maryland Astrobiology Consortium, NASA, and STScI.

Mars is often considered to be the planet most similar to the Earth. Earth however, is capable of supporting life, Mars on the other hand could not. There was once a time when it was warmer and wetter and could support life. Exploring life on Earth shows us that bacteria known as extremophiles can live in the most harsh conditions on Earth, it may just be possible that there are places on Mars that could also support these hardy forms of life. A new paper explores that possibility by studying the most extreme Earth-based bacteria that could survive under ground on Mars.

January 2, 2025January 2, 2025 by Brian Koberlein

Could Habitable White Dwarf Planets Retain Their Oceans? Maybe.

An artist’s impression of the white dwarf star WD1054–226 orbited by clouds of planetary debris and a major planet in the habitable zone. Credit Mark A. Garlick / markgarlick.com Licence type Attribution (CC BY 4.0)

Potentially habitable exoplanets are so incredibly common that astronomers have started to consider more unusual situations where life might arise. Perhaps life can be found on the moon of a hot Jupiter or lingering in the warm ocean of a rogue planet. Recently, there has even been the idea that habitable worlds might orbit white dwarfs. We know some white dwarfs have planets, and despite lacking nuclear fusion, white dwarfs do emit enough light and heat to have a habitable zone. But the question remains whether a planet could retain a water-rich environment through the red giant stage of a star before it becomes a white dwarf. This is the focus of a new study on the arXiv.

January 2, 2025January 2, 2025 by Matt Williams

Is There a Fundamental Logic to Life?

Will it be possible someday for astrobiologists to search for life "as we don't know it"? Credit: NASA/Jenny Mottar

One of the more daunting questions related to astrobiology—the search for life in the cosmos—concerns the nature of life itself. For over a century, biologists have known that life on Earth comes down to the basic building blocks of DNA, RNA, and amino acids. What’s more, studies of the fossil record have shown that life has been subject to many evolutionary pathways leading to diverse organisms. At the same time, there is ample evidence that convergence and constraints play a strong role in limiting the types of evolutionary domains life can achieve.

For astrobiologists, this naturally raises questions about extraterrestrial life, which is currently constrained by our limited frame of reference. For instance, can scientists predict what life may be like on other planets based on what is known about life here on Earth? An international team led by researchers from the Santa Fe Institute (SFI) addressed these and other questions in a recent paper. After considering case studies across various fields, they conclude that certain fundamental limits prevent some life forms from existing.

January 2, 2025January 2, 2025 by Andy Tomaswick

Using an Oil Industry Framework to Map Space Resources

ISRU system concept for autonomous construction on Mars. Credit: NASA/JPL-Caltech

Cracking the chicken-and-egg problem of utilizing resources in space has been a difficult challenge for over half a century. Getting enough infrastructure built up is necessary to collect those resources effectively, but doing so is too expensive without using the resources themselves. Trying to crack that problem has been the focus of a variety of space exploration enthusiasts, and one of them, Don Barker, is currently the Gateway HALO Utilization & Visiting Vehicle Integration Lead at ARES Corporation. He published a paper in 2020 that detailed how the space exploration industry could use a modified version of a framework from the oil and gas industry, which he calls the Planetary Resource Management System (PRMS), to calculate where we should focus on settlement efforts.

January 2, 2025January 2, 2025 by Brian Koberlein

The Webb Captures Spectra of Trans-Neptunian Objects, and Reveals a History of Our Solar System

Artistic representation of the distribution of trans-Neptunian objects in the planetesimal disk, with overlaid representative spectra of each compositional group highlighting the dominant molecules on their surfaces. Credit: William D. González Sierra/Florida Space Institute, University of Central Florida

Trans-Neptunian Objects (TNOs) are small planetoids that orbit the Sun beyond Neptune and Pluto. Their dark and icy character contains the remnant of the early solar system, and as such, they have the potential to reveal its history. But since they are small, distant, and dim, TNOs are very difficult to study. We know that different groups of TNOs have unique histories based on their surface colors and orbits. A new study has looked at their spectra, and it reveals a rich diversity unseen before now.

January 2, 2025January 2, 2025 by Mark Thompson

This Particle Only Has Mass When Moving in One Direction

The quasiparticle, called a semi-Dirac fermion, was first theorized 16 years ago, but was only recently spotted inside a crystal of semi-metal material called ZrSiS. The observation of the quasiparticle opens the door to future advances in a range of emerging technologies from batteries to sensors, according to researchers who made the discovery. Credit: Yinming Shao / Penn State

Particle physics is not everyone’s cup of tea. A team of physicists have theorised the existence of a strange type of particle that behaves differently depending on its direction of travel—massless in one direction but possessing mass when moving the other way! This strange, elusive particle, known as a semi-Dirac fermion or “quasiparticle,” has actually been observed in action. To detect it, researchers cooled a semi-metal crystal to near absolute zero, exposed it to a powerful magnetic field and infrared light, and successfully captured the signal of these unusual quasiparticles.

January 1, 2025January 1, 2025 by Mark Thompson

Crisscrossing Dust Devil Tracks Across the Surface of Mars

Dust Devils on Mars - NASA/JPL-Caltech/University of Arizona

An incredible image of Mars has been released that captures the relentless activity of dust devils, swirling across the planet’s surface. These Martian whirlwinds form, move across the surface and dissipate before others take their place. The image was taken by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter in September 2022 and shows part of the Haldane Crater, where dust devils have left their mark on the landscape. Scientists study the image tracks and the rate at which dust accumulates on Mars, helping them better understand the planet’s atmospheric processes.

January 1, 2025January 1, 2025 by Andy Tomaswick

A Long-Term Lunar Infrastructure Hub Named After the Object That Created the Moon

Getting back to the Moon is the primary goal of NASA’s Artemis program, but what do we do once we get there? That is the challenge tackled by a group of students at the University of Illinois Urbana-Champaign, who wrote a proposal for a lunar infrastructure module they call the Trans-lunar Hub for Exploration, ISRU, and Advancement – or THEIA, after the proposed object that crashed into the Earth that created the Moon as we know it today. Their submission was part of the NASA Revolutionary Aerospace Systems Concepts – Academic Linkage project, where teams from various academic institutions submitted papers focusing on the theme of Sustained Lunar Evolution for 2024.

January 1, 2025January 1, 2025 by Brian Koberlein

New Study of Supernovae Data Suggests That Dark Energy is an Illusion

The evolution of the Universe as we know it. Credit: NASA

Dark energy is central to our modern understanding of cosmology. In the standard model, dark energy is what drives the expansion of the Universe. In general relativity, it’s described by a cosmological constant, making dark energy part of the structure of space and time. But as we’ve gathered more observational evidence, there are a few problems with our model. For one, the rate of cosmic expansion we observe depends on the observational method we use, known as the Hubble tension problem. For another, while we assume dark energy is uniform throughout the cosmos, there are some hints suggesting that might not be true. Now a new study argues we’ve got the whole thing wrong. Dark energy, the authors argue, doesn’t exist.