Science & TechnologyS


Telescope

JWST spots new rings, moons around Uranus


WEBB Space Telescope
Mon, 18 Dec 2023 19:59 UTC
uranus rings moons
© JWST/NASARings and moons of Uranus captured by the James Web Space Telescope
NASA's James Webb Space Telescope recently trained its sights on unusual and enigmatic Uranus, an ice giant that spins on its side. Webb captured this dynamic world with rings, moons, storms, and other atmospheric features - including a seasonal polar cap. The image expands upon a two-color version released earlier this year, adding additional wavelength coverage for a more detailed look.

With its exquisite sensitivity, Webb captured Uranus' dim inner and outer rings, including the elusive Zeta ring - the extremely faint and diffuse ring closest to the planet. It also imaged many of the planet's 27 known moons, even seeing some small moons within the rings.

In visible wavelengths as seen by Voyager 2 in the 1980s, Uranus appeared as a placid, solid blue ball. In infrared wavelengths, Webb is revealing a strange and dynamic ice world filled with exciting atmospheric features.

One of the most striking of these is the planet's seasonal north polar cloud cap. Compared to the Webb image from earlier this year, some details of the cap are easier to see in these newer images. These include the bright, white, inner cap and the dark lane in the bottom of the polar cap, toward the lower latitudes.
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Galaxy

Astronomers detect almost 100 new extremely metal-poor galaxies

Tomasz Nowakowski
Phys.org
Fri, 15 Dec 2023 00:00 UTC
galaxies
© unknownTwo most metal-poor galaxies identified in this work. The left, middle and right.
By analyzing the early data from the Dark Energy Spectroscopic Instrument (DESI), an international team of astronomers has identified 95 new extremely metal-poor galaxies at a low redshift. The finding is detailed in a paper published December 1 on the pre-print server arXiv.

Extremely metal-poor galaxies (XMPGs) are the ones with metallicity below 0.1 of the solar metallicity. Given that these galaxies are chemically unevolved, they can serve as excellent laboratories for investigating the chemical evolution theories of galaxies and studying the physical processes in the early stages of their evolution.

Although XMPGs are assumed to be quite common at high redshift, they are difficult to observe due to their low masses. Therefore, astronomers are interested in the observations of local XMPGs at low redshift, as they are perceived as possible analogs of primeval high-redshift young galaxies of this type in terms of mass and metallicity.

Now, a group of astronomers led by Hu Zou of the University of Chinese Academy of Sciences in Beijing, China, has obtained a large sample of XMPGs based on the early data from DESI.
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Info

The 8.5-year rhythm of Earth's inner core

Tejasri Gururaj
Phys Org
Mon, 18 Dec 2023 18:55 UTC
tilted inner core wobble
© Dr. Ding/Nature Communications. 10.1038/s41467-023-43894-9.A schematic depiction of the tilted inner core wobble.
Researchers from China have confirmed the existence of an approximately 8.5-year Inner Core Wobble (ICW) in both polar motion and length-of-day variations, revealing a static tilt of about 0.17 degrees between the Earth's inner core and mantle, challenging traditional assumptions and providing insights into the Earth's internal dynamics and density distribution.

The findings of the study are published in Nature Communications.

The Earth's inner core is a solid, dense sphere composed primarily of iron and nickel. Located beneath the liquid outer core, it spans a radius of about 1,200 kilometers (746 miles). This region plays a crucial role in Earth's geophysical processes, influencing the planet's magnetic field and contributing to the overall dynamics of the Earth's interior.

Understanding the properties and behavior of the inner core is essential for unraveling mysteries related to Earth's structure, seismic activity, and magnetic field.

The ICW refers to the wobbling motion of the Earth's inner core around its rotation axis. This phenomenon is characterized by a periodic oscillation of the inner core's figure axis.

A new study has confirmed that the ICW of Earth has a periodic motion with a cycle lasting approximately 8.5 years. This wobbling motion has been observed in measurements of polar motion, the Earth's rotational axis' periodic movement and length-of-day variations (ΔLOD), and the changes in Earth's rotational speed.

Professor Hao Ding, co-author of this research and Dean of the Geophysics Department at Wuhan University, was inspired by the unconventional density structures revealed in Earth's free oscillation.

He told Phys.org, "My then Ph.D. student, Dr. Yachong An, and I discovered an 8.5-year signal in PM and ΔLOD, prompting us to conduct the present study."
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Galaxy

Astronomers discover 25 'stripped stars' that may be a missing link in supernova science

Robert Lea
Live Science
Thu, 14 Dec 2023 18:40 UTC
The Large Magellanic Cloud
© NASA/Swift/ Immler (Goddard)/ Siegel (Penn StateThe Large Magellanic Cloud. a satellite galaxy of the Milky Way where these stripped stars were found.
Astronomers have discovered 25 stars in two satellite galaxies of the Milky Way that have had their hydrogen-rich outer layers stripped away by a binary companion, leaving them as exposed helium stars. The hydrogen-stripped stars represent the progenitors of a special type of supernova — an explosion that occurs when massive stars die and birth black holes or neutron stars — and fill in a glaring hole in our understanding of some of the universe's most powerful events.

When massive stars die in bright supernova explosions, they often outshine the combined light of every star in the galaxy around them. Some of these events lack evidence of hydrogen, so it follows that they must begin with stars that also lack hydrogen in their outer layers. Until now, evidence of these hydrogen-stripped stars has largely eluded scientists.

This is the first time a population of these hydrogen-stripped stars has ever been discovered.
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Telescope

Has dark matter's identity been revealed? Scientists searching for mysterious hypothetical particle may soon have an answer

Micah Hanks
The Debrief
Tue, 12 Dec 2023 00:00 UTC
pulsar
© UnknownPulsar
Scientists may be closing in on solving the mystery of dark matter, a hypothetical, nonluminous material that is believed to comprise a large majority of the mass in our universe, in new research that may link it to the existence of a hypothetical subatomic particle.

Among the primary questions scientists have about dark matter is what it could be made of. However, new research by an international team of astrophysicists proposes a possible candidate, meaning that this elusive cosmic material might be detectable in the form of a glow emanating from certain kinds of stars.

The research, conducted by astrophysicists at the universities of Amsterdam and Princeton, suggests that dark matter, which presently is believed to constitute around 85% of the matter in the universe, could be composed of hypothetical particles known as axions.

First proposed in the 1970s to resolve an unrelated problem involving neutrons, axions are of interest to dark matter researchers because if they possess a low mass within a certain range, they could be good candidates in the search for dark matter. Not only that, but they might help to potentially explain how and why dark matter has remained so elusive.
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Satellite

Voyager 1 is returning garbled mess of 1s and 0s from space. NASA is baffled

Carly Cassella
Science Alert
Thu, 14 Dec 2023 15:32 UTC
Raumsonde Voyager 1
© dpaNASA illustration of the American space probe "Voyager 1". The probe has been flying through space since its launch on September 5, 1977.
Voyager 1, the most distant human-made object from Earth, is sending back a repetitive jumble of 1s and 0s that don't make any sense.

Scientists at NASA are desperately trying to fix the glitch from 24 billion kilometers (15 billion miles) away .

The probe can still receive commands from Earth but messages to interstellar space require approximately 22.5 hours of travel. That means it will take days before experts know if their attempts to restore the probe's nearly 50-year-old computers have worked or not.

This isn't the first time that Voyager 1 has sent back random readouts. In 2022, the probe started returning some of its data through a broken computer onboard, corrupting the outgoing messages.

Engineers at NASA managed to figure the problem out and fix it. But it took several months.
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Saturn

Signs of life shooting from Saturn's moon could be collected with spacecraft, scientists say

Rahul Rao
Live Science
Sun, 10 Dec 2023 08:48 UTC
ice plumes enceladus
© NASAThis artistic rendering shows ice plumes being ejected from Enceladus at major speeds.
When NASA's Cassini spacecraft turned its instruments to Saturn's moon Enceladus, it observed plumes of ice shooting up from the moon's surface at speeds of about 900 miles per hour (1,448 kilometers per hour). These geysers seemed to be the tendrils of a vast subsurface ocean — and made scientists curious if their fluid might carry life signs, organic molecules.

But if scientists want to study those organic molecules, they'll need to find a careful way of collecting them without destroying them. There is now good news on that front: If one lab experiment is correct, then any possible amino acids in those geysers' fluid are expected to easily survive contact with a spacecraft.

Researchers learned this in the lab by working with a physical apparatus designed to examine collisions. The researchers created ice particles by pushing water through a high-voltage needle; the charge fragmented the water into tiny droplets, each of which crystallized into an ice grain as it entered a vacuum. Then, the researchers shot the hardened grains through a spectrometer and imaged each grain as well as recorded impact times.

Comment: See also: Scientists discovered a crucial element for life gushing out of Saturn's icy ocean moon

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Microscope 1

New genes found that can arise 'from nothing'

University of Helsinki
Phys.org
Fri, 08 Dec 2023 12:16 UTC
DNA replication 1
© Ari LöytynojaResearchers studied an error mechanism in DNA replication, and noticed that some errors create palindromes that can fold into hairpin structures.
The complexity of living organisms is encoded within their genes, but where do these genes come from? Researchers at the University of Helsinki resolved outstanding questions around the origin of small regulatory genes, and described a mechanism that creates their DNA palindromes. Under suitable circumstances, these palindromes evolve into microRNA genes.

The human genome contains ca. 20,000 genes that are used for the construction of proteins. Actions of these classical genes are coordinated by thousands of regulatory genes, the smallest of which encode microRNA molecules that are 22 base pairs in length. While the number of genes remains relatively constant, occasionally, new genes emerge during evolution. Similar to the genesis of biological life, the origin of new genes has continued to fascinate scientists.

All RNA molecules require palindromic runs of bases that lock the molecule into its functional conformation. Importantly, the chances of random base mutations gradually forming such palindromic runs are extremely small, even for the simple microRNA genes.

Hence, the origin of these palindromic sequences has puzzled researchers. Experts at the Institute of Biotechnology, University of Helsinki, Finland, resolved this mystery, describing a mechanism that can instantaneously generate complete DNA palindromes and thus create new microRNA genes from previously noncoding DNA sequences.
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Info

Whale-SETI: Groundbreaking encounter with humpback whales reveals potential for non-human intelligence communication


SETI Institute
Tue, 12 Dec 2023 17:20 UTC
Tail of a Whale
© Jodi Frediani
Mountain View, CA -- A team of scientists from the SETI Institute, University of California Davis and the Alaska Whale Foundation, had a close encounter with a non-human (aquatic) intelligence. The Whale-SETI team has been studying humpback whale communication systems in an effort to develop intelligence filters for the search for extraterrestrial intelligence. In response to a recorded humpback 'contact' call played into the sea via an underwater speaker, a humpback whale named Twain approached and circled the team's boat, while responding in a conversational style to the whale 'greeting signal.' During the 20-minute exchange, Twain responded to each playback call and matched the interval variations between each signal.

A description and analysis of the encounter appears in a recent issue of the journal Peer J. entitled: "Interactive Bioacoustic Playback as a Tool for Detecting and Exploring Nonhuman Intelligence: "Conversing" with an Alaskan Humpback Whale." "We believe this is the first such communicative exchange between humans and humpback whales in the humpback "language," said lead author Dr. Brenda McCowan of U.C. Davis. "Humpback whales are extremely intelligent, have complex social systems, make tools - nets out of bubbles to catch fish -, and communicate extensively with both songs and social calls," said coauthor Dr. Fred Sharpe of the Alaska Whale Foundation.
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Fireball 3

The Geminids are still a mystery


Spaceweather.com
Wed, 13 Dec 2023 16:21 UTC
Above: Geminids over the Czech Republic in 2018.
© Petr HorálekAbove: Geminids over the Czech Republic in 2018.
Every great mystery novel has an unexpected twist. Apparently the same is true of meteor showers.

A paper published in the Planetary Science Journal reports a surprising new twist in the mystery of the Geminids, a strong annual meteor shower that has puzzled astronomers for more than a century.

"Our work has upended years of belief about 3200 Phaethon, the source of the Geminids," says co-author Karl Battams of the Naval Research Lab. "It's not what we thought it was."

The Geminids peak every year in mid-December, scattering hundreds of bright meteors across northern winter skies. Numerically it is the best meteor shower of the year.

As meteor showers go, Geminids are newcomers. They first appeared in the mid-1800s when an unknown stream of debris crossed Earth's orbit. Surprised, 19th century astronomers scoured the sky for the parent comet, but they found nothing. The search would continue for another 100 years.

Enter NASA. In 1983, the space agency's Infrared Astronomical Satellite (IRAS) found an object now called "3200 Phaethon." It was definitely the source of the Geminids. The orbit of 3200 Phaethon was such a close match to that of the Geminid debris stream, no other conclusion was possible. Yet here was a puzzler: 3200 Phaethon appeared to be a rocky asteroid.
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