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Category: space – Page 5

Hubble shows star formation in Andromeda galaxy is winding down

A new study using data from NASA’s Hubble Space Telescope finds that star formation in the nearby Andromeda galaxy has undergone a 500-million-year decline, with an even steeper drop in the last 40 million years. Andromeda, a spiral galaxy comparable in size to our Milky Way, is close enough to be seen with the unaided eye from areas with dark skies. Located about 2.5 million light-years from Earth—practically our cosmic backyard—Andromeda offers an opportunity for astronomers to examine its stellar populations in detail, leading to a better understanding of the past of galaxies like our own.

The results were published Monday in The Astrophysical Journal.

Commander Jessica Meir and Crew Check Spacesuits, Prep for Spacewalks

The seven-member Expedition 75 crew worked throughout Tuesday on spacesuit checks, eye exams, and exercise research aboard the International Space Station. Earth imagery and lab inventory duties rounded out the day for the orbital residents.

NASA has scheduled three spacewalks in August to continue upgrading solar arrays, replace a communications antenna, and connect power and data cables in support of space station operations. Station commander Jessica Meir and flight engineer Anil Menon, both from NASA, will conduct the first spacewalk beginning at 7:35 a.m. EDT on Thursday, Aug. 6. The duo will spend about six-and-a-half hours in the vacuum of space preparing the orbital outpost for its seventh roll out solar array to augment its power system. Mission managers will discuss the upcoming spacewalks during a news conference on NASA+ beginning a at 2 p.m. EDT, Thursday, July 30, from NASA’s Johnson Space Center in Houston.

Meir and Menon joined flight engineers Jack Hathaway of NASA and Sophie Adenot of ESA (European Space Agency) in the Quest airlock and checked out a pair of spacesuits. The quartet first verified the suits for comfort, mobility, and fitness for the upcoming spacewalks. Next, they powered on the suits and tested the life support and electronics systems. NASA will soon announce the spacewalkers for the second and third spacewalks.

Tabby’s star may be orbited by a planetary-mass companion

By analyzing data from NASA’s Transiting Exoplanet Survey Satellite (TESS) and conducting new radial velocity measurements, U.K. and French astronomers have found evidence that the mysterious Tabby’s star may be orbited by an object about nine times more massive than Jupiter. The new findings are published on the preprint server arXiv.

KIC 8,462,852, also known as Tabby’s star (after the discoverer Tabetha S. Boyajian), is a peculiar F3V main-sequence star showcasing deep, irregular flux variations of up to 20% in its light curve. The star is about 50% larger and more massive than the sun, with an effective temperature of 6,750 K. In 2021, it was found that Tabby’s star is part of a binary system with a red dwarf companion, which is about half the size and mass of our sun.

Several hypotheses have been proposed to explain the irregular dips in the light curve of Tabby’s star, including a family of exocomets or planetesimal fragments. It was even proposed that the flux variations could be caused by extraterrestrial megastructures, which was later debunked. However, the origin of these dips remains uncertain.

Risks of solar storms may be underestimated, warn researchers

The effects of extreme space weather may be larger than previously thought, research in the journal Nature reveals. The paper, titled “Regression to the mean can explain saturation of geomagnetic storms,” is led by Dr. Nithin Sivadas of NASA’s Goddard Space Flight Center and co-authored by Dr. Maria Walach from Lancaster University.

Space weather—caused by fluctuating electric fields in Earth’s magnetic field and upper atmosphere—can affect technologies on and around Earth in several ways. Extreme geomagnetic storms are among the less frequent but more severe forms of space weather.

Extreme geomagnetic storms are temporary disturbances in the plasma and magnetic field around Earth that can disrupt global satellite communications, cause extensive power outages and affect how much radiation astronauts and pilots are exposed to.

The global biogeography of passerine songs

Although bird songs are classic models for understanding the evolution of vocal communication, their global diversity has long made the development of a unifying framework challenging. By analyzing the acoustic architecture of songs from more than 3,000 passerine species worldwide, we show that this acoustic space can be structured around eight elemental motifs. The differential use of these motifs is driven by a combination of species’ biological traits (social organization, morphology, and mating system) and the physics of sound propagation. In tropical rainforests, environmental filtering for transmission efficiency favors structurally simple motifs, such as flat whistles.

Extragalactic positron-annihilation hotspots might mean Milky Way produces far more positrons than thought

Positrons—the antimatter counterpart of electrons—are created in high-energy cosmic processes. When normal matter meets its antimatter counterpart, they annihilate, or vanish, and produce a distinctive 511 keV gamma-ray signal. Scientists use this signal to detect where these annihilations occur.

Now, 20 years’ worth of this kind of data has revealed that positron annihilations might be happening in unexpected places and at far greater rates than previously thought. The new study, published in Astronomy & Astrophysics, describes how astronomers are interpreting a new positron annihilation map and whether the results represent true annihilations or just imaging artifacts.

Magnetic fingerprint of a cosmic explosion detected for the first time

Astronomers have made a series of landmark observations of one of the universe’s most violent events. Using the U.S. National Science Foundation Very Large Array (NSF VLA) radio telescope, which is operated by the U.S. National Science Foundation National Radio Astronomy Observatory (NSF NRAO), the team detected polarized light from a gamma-ray burst (GRB) afterglow for the first time at radio wavelengths.

It also marks the first time scientists have detected Faraday rotation in a GRB, a phenomenon in which magnetic fields cause the polarization of light to twist as it travels through space, revealing how the magnetic environment of these explosions interacts with the light they produce. The findings, led by researchers at the University of Arizona and the University of Utah, offer a new window into the extreme physics driving these titanic explosions.

The paper has been submitted to The Astrophysical Journal Letters and is available on the arXiv preprint server.

Quantum dots reveal hidden light waves on metal surfaces

Photographs can reveal things that are otherwise impossible for the naked eye to see, be they distant galaxies or microscopic cells. Researchers at Osaka Metropolitan University have developed a practical and versatile imaging technique that makes another usually invisible phenomenon visible: surface plasmon polaritons (SPPs), light waves that travel along metal surfaces.

The new method, published in the journal Nano Letters, could boost the development of next-generation optical and plasmonic technologies.

SPPs are electromagnetic waves that travel along the boundary between a metal and a dielectric material, such as air or glass. Unlike ordinary light, which spreads freely through three-dimensional space, SPPs remain tightly confined to this interface, allowing them to be guided and manipulated at the nanoscale. This unique property makes them fundamental to emerging technologies including ultrasensitive sensors, optical circuits and quantum devices.

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