But there’s a quantum catch.
Category: cosmology – Page 13
Quantum physics is a very diverse field: it describes particle collisions shortly after the Big Bang as well as electrons in solid materials or atoms far out in space. But not all quantum objects are equally easy to study. For some—such as the early universe—direct experiments are not possible at all.
However, in many cases, quantum simulators can be used instead: one quantum system (for example, a cloud of ultracold atoms) is studied in order to learn something about another system that looks physically very different, but still follows the same laws, i.e. adheres to the same mathematical equations.
It is often difficult to find out which equations determine a particular quantum system. Normally, one first has to make theoretical assumptions and then conduct experiments to check whether these assumptions prove correct.
Physicists have proposed a solution to a long-standing puzzle surrounding the GD-1 stellar stream, one of the most well-studied streams within the galactic halo of the Milky Way, known for its long, thin structure, and unusual spur and gap features.
The team of researchers, led by Hai-Bo Yu at the University of California, Riverside, proposed that a core-collapsing self-interacting dark matter (SIDM) “subhalo” — a smaller, satellite halo within the galactic halo — is responsible for the peculiar spur and gap features observed in the GD-1 stellar stream.
Study results appear in The Astrophysical Journal Letters in a paper titled “The GD-1 Stellar Stream Perturber as a Core-collapsed Self-interacting Dark Matter Halo.” The research could have significant implications for understanding the properties of dark matter in the universe.
An international team of astronomers have investigated a large Galactic supernova remnant designated G278.94+1.35. Results of the study, published Dec. 30 on the pre-print server arXiv, shed more light on the properties of this remnant.
Supernova remnants (SNRs) are diffuse, expanding structures resulting from a supernova explosion. They contain ejected material expanding from the explosion and other interstellar material that has been swept up by the passage of the shockwave from the exploded star.
G278.94+1.35 is a supernova remnant in the Milky Way, discovered in 1988. It has an estimated linear diameter of about 320 light years and its age is assumed to be about 1 million years. The distance to G278.94+1.35 is estimated to be some 8,800 light years.
Astronomers using the James Webb Space Telescope have used a distortion in space to reveal over 40 individual stars in a galaxy 6.5 billion light-years from the Milky Way—halfway back to the beginning of the universe. It’s the largest number of individual stars ever detected in the distant universe.
The unique image, which takes advantage of JWST’s high-resolution optics, was only possible because the light from 44 stars in a distant galaxy was magnified by a massive cluster of galaxies in front of it called Abell 370.
This technique, called gravitational lensing—also known as an “Einstein ring” because it was predicted by the famous scientist Albert Einstein—works when the gravitational field of a foreground object distorts the space around it. Light is bent from an object behind it into circular rings or arcs, both revealing the existence of something in the background and, crucially, magnifying it by factors of hundreds or even thousands. In this case, an arc was visible, dubbed the “Dragon Arc.”
May the Force Be Among Us: Exploring our MultiVerse with the help of Star Wars and other movies with Jean-Francois Vezina from the series \.
Scientists are diving deep into the origins of supermassive black holes, using recent gravitational wave detections as a key tool.
By leveraging signals from smaller black holes, researchers hope to detect the harder-to-catch waves from supermassive pairs, potentially unlocking the secrets of their formation and growth.
Unveiling the mystery of supermassive black holes.
For the first time, the NASA/ESA/CSA James Webb Space Telescope has detected and “weighed” a galaxy that not only existed about 600 million years after the Big Bang, but also has a mass that is similar to what our Milky Way galaxy’s mass might have been at the same stage of development.
Other galaxies Webb has detected at this period in the history of the universe are significantly more massive. Nicknamed the Firefly Sparkle, this galaxy is gleaming with star clusters—10 in all—each of which researchers examined in great detail. Their work is published in Nature.
“I didn’t think it would be possible to resolve a galaxy that existed so early in the universe into so many distinct components, let alone find that its mass is similar to our own galaxy’s when it was in the process of forming,” said Lamiya Mowla, co-lead author of the paper and an assistant professor at Wellesley College in Massachusetts. “There is so much going on inside this tiny galaxy, including so many different phases of star formation.”
There might not be a mysterious ‘dark’ force accelerating the expansion of the Universe after all. The truth could be much stranger – bubbles of space where time passes at drastically different rates.
The passage of time isn’t as constant as our experience with it suggests. Areas of higher gravity experience a slower pace of time compared with areas where gravity is weaker, a fact that could have some pretty major implications on how we compare rates of cosmic expansion according to a recently developed model called timescape cosmology.
Discrepancies in how fast time passes in different regions of the Universe could add up to billions of years, giving some places more time to expand than others. When we look at distant objects through these time-warping bubbles, it could create the illusion that the expansion of the Universe is accelerating.
Back when the Universe was new, following the Big Bang some 13.8 billion years ago, galaxies took a bit of time to assemble themselves from the surrounding primordial soup.
A new discovery right at the end of the Cosmic Dawn is challenging how long we thought that assembly took. JWST has spotted a huge, ultramassive galaxy as it appeared 12.8 billion years ago, so intricately structured that it can only belong to the most spectacular category of galaxies: the grand design spiral.
The galaxy’s name is Zhúlóng, after the Torch Dragon of Chinese myth, and its discovery has been detailed in a paper uploaded to preprint server arXiv ahead of peer review and publication.