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Category: space – Page 42

MeerKAT discovers record-breaking cosmic laser halfway across the universe

Astronomers using the MeerKAT radio telescope in South Africa have discovered the most distant hydroxyl megamaser ever detected. It is located in a violently merging galaxy more than 8 billion light-years away, opening a new radio astronomy frontier.

Hydroxyl megamasers are natural “space lasers”—extremely bright radio-wavelength emissions produced when hydroxyl molecules in gas-rich, merging galaxies crash into one another. These cosmic collisions compress gas and stimulate large reservoirs of hydroxyl molecules to amplify radio emission.

The physical mechanism is very similar to lasers on Earth, but operates at a much longer wavelength of light of about 18 centimeters, rather than the optical light that our eyes can see. When this special radio light is exceptionally bright, it is termed a megamaser—a “cosmic beacon” that can be seen across vast stretches of the universe.

Astronomers shocked by how these giant exoplanets formed

JWST just found evidence that some “super-Jupiters” may have formed like planets, not failed stars. A distant star system with four super-sized gas giants has revealed a surprise. Thanks to JWST’s powerful vision, astronomers detected sulfur in their atmospheres — a chemical clue that they formed like Jupiter, by slowly building solid cores. That’s unexpected because these planets are far bigger and orbit much farther from their star than models once allowed.

Gas giants are enormous planets made primarily of hydrogen and helium. They may contain dense central cores, but unlike Earth, they do not have solid surfaces you could stand on. In our solar system, Jupiter and Saturn are classic examples. Beyond our neighborhood, astronomers have identified many gas giant exoplanets, some far larger than Jupiter. The most massive of these worlds begin to resemble brown dwarfs, substellar objects sometimes called “failed stars” because they do not fuse hydrogen.

This overlap raises a major question in astronomy. How exactly do these massive planets form? One possibility is core accretion, the same process believed to have created Jupiter and Saturn. In this scenario, a solid core slowly builds up inside a disk of dust and ice, gathering rocky and icy material until it becomes massive enough to pull in surrounding gas. Another possibility is gravitational instability, where a swirling cloud of gas around a young star collapses quickly under its own gravity, forming a large object more like a brown dwarf.

Simulations show a path to ‘ideal glass’ with crystal-like entropy

The types of glass that we encounter in everyday life, such as window glass or smartphone screens, are disordered solids. This means that they consist of particles locked in place, like those in solids, but arranged randomly, similarly to how they would be in a liquid.

Almost a century ago, Walter Kauzmann, who was a chemistry professor at Princeton University at the time, was confronted with the possible existence of a so-called ideal glass, an amorphous system with the entropy of a crystal. This is a glass in which particles are still arranged randomly, but the particles fill space so efficiently that there is only one possible arrangement, as opposed to the many disordered arrangements of conventional glass.

Kauzmann’s theoretical proposals inspired numerous other physicists to explore the idea of this perfectly equilibrated glass. Previous studies suggested that this elusive state could not be reached using conventional cooling processes.

Rydberg atoms detect clear signals from a handheld radio

For the first time, a team of US researchers has used sensors containing highly excited Rydberg atoms to detect signals from an ordinary handheld radio. Through a careful approach to demodulating the incoming signals, Noah Schlossberger and colleagues at the National Institute of Standards and Technology (NIST) were able to recover audio encoded in multiple public radio channels, with promising implications for everyday uses in consumer electronics. The research has been published in Physical Review Applied.

In a Rydberg atom, a single electron is excited to an extremely high energy level, pushing it far from its host atom’s nucleus. From a distance, these atoms resemble a single electron orbiting a positively charged ion.

When any atom is exposed to an external electric field, the positions of its electrons’ energy levels shift through a process called the Stark effect. Yet in a Rydberg atom, the shift becomes far more pronounced, causing particularly striking changes in the spectral patterns produced when the atom is probed by a laser.

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