Lifeboat Foundation: Safeguarding Humanity
Toggle light / dark theme

Blog

Category: cosmology – Page 323

The Grantecan finds the farthest black hole that belongs to a rare family of galaxies

An international team of astronomers has identified one of the rarest known classes of gamma-ray emitting galaxies, called BL Lacertae, within the first 2 billion years of the age of the Universe. The team, that has used one of the largest optical telescope in the world, Gran Telescopio Canarias (GTC), located at the Observatorio del Roque de los Muchachos (Garafía, La Palma), consists of researchers from the Universidad Complutense de Madrid (UCM, Spain), DESY (Germany), University of California Riverside and Clemson University (USA). Their finding is published in The Astrophysical Journal Letters.

Only a small fraction of emits gamma rays, which are the most extreme form of light. Astronomers believe that these highly energetic photons originate from the vicinity of a supermassive black hole residing at the centers of these galaxies. When this happens, they are known as active galaxies. The black hole swallows matter from its surroundings and emits jets or, in other words, collimated streams of matter and radiation. Few of these active galaxies (less than 1%) have their jets pointing by chance toward Earth. Scientists call them blazars and are one of the most powerful sources of radiation in the universe.

Blazars come in two flavors: BL Lacertae (BL Lac) and flat-spectrum radio-quasars (FSRQs). Our current understanding about these mysterious astronomical objects is that FSRQs are relatively young active galaxies, rich in dust and gas that surround the central black hole. As time passes, the amount of matter available to feed the black hole is consumed and the FSRQ evolves to become a BL Lac object. “In other words, BL Lacs may represent the elderly and evolved phase of a blazar’s life, while FSRQs resemble an adult,” explains Vaidehi Paliya, a DESY researcher who participated in this program.

This Whiter-Than-White Paint Is Like the Opposite of Vantablack

CREATING ARTIFICIAL SKIES IN UNDERGROUND HABITATS ON MARS & MERCURY. This will be an interesting subject for much deliberation in the future: how to best create artificial skies in sealed habitats. Metamaterial vantablack is a surface so perfectly dark that if you stood in a room where the ceiling, walls and floor were covered with it, you would feel like you were floating in black space. Disneyland must get off its butt and create a big room like this. Now a new paint (not quite the opposite of vantablack as it claims) has been invented, which will reflect back nearly 100% of light hitting it, an interesting way to augment existing lighting in a building by painting the ceiling with the stuff.

And here is something which I told you before: if the human eye stares at a totally uniform color, with no discernable features it doesn’t know where to focus, and psychologically can see this as a kind of “sky.” Since there is nothing to focus on, the eye assumes it is the far away sky and focusses to infinity or goes into its least-energetic focusing mode, as in looking at a blank sky.

View a large computer screen with a totally uniform color, through a tube which blocks the edge of the screen from view. You already see this effect with this small experiment.

New paint reflects nearly all light hitting it, can help cool down space probes:

A team of scientists have created a white paint that’s so white, they say, that it reflects 95.5 percent of sunlight that reaches its surface.

Essentially, it’s the exact opposite of Vantablack, the substance that makes objects appear so dark, by absorbing close to 100 percent of light that hits them, that it’s as if you’re staring into a black hole.

Continue reading “This Whiter-Than-White Paint Is Like the Opposite of Vantablack” | >

A major milestone for an underground dark matter search experiment

Crews working on the largest U.S. experiment designed to directly detect dark matter completed a major milestone last month, and are now turning their sights toward startup after experiencing some delays due to global pandemic precautions.

U.S. Department of Energy officials on Sept. 21 formally signed off on project completion for LUX-ZEPLIN, or LZ: an ultrasensitive experiment that will use 10 metric tons of liquid xenon to hunt for signals of interactions with theorized dark matter particles called WIMPs, or weakly interacting massive particles. DOE’s project completion milestone is called Critical Decision 4, or CD-4.

Dark matter makes up an estimated 85 percent of all matter in the universe. We know it’s there because of its observed gravitational effects on normal matter, but we don’t yet know what it is. LZ is designed to detect the two flashes of light that occur if a WIMP interacts with the nucleus of a xenon atom.

Precision metrology closes in on dark matter

Optical clocks are so accurate that it would take an estimated 20 billion years—longer than the age of the universe—to lose or gain a second. Now, researchers in the U.S. led by Jun Ye’s group at the National Institute of Standards and Technology and the University of Colorado have exploited the precision and accuracy of their optical clock and the unprecedented stability of their crystalline silicon optical cavity to tighten the constraints on any possible coupling between particles and fields in the standard model of physics and the so-far elusive components of dark matter.

The existence of dark matter is indirectly evident from gravitational effects at galactic and cosmological scales, but beyond that, little is known of its nature. One of the effects that falls out of theoretical analysis of dark matter coupling to particles in the standard model of physics is a resulting oscillation in . Ye and collaborators figured that if their world-class metrology equipment could not detect these oscillations, then this apparently null result would be useful confirmation that the strength of dark matter interactions with particles in the standard model of physics must be even lower than dictated by the constraints so far on record.

New theory on the origin of dark matter

A recent study from the University of Melbourne proposes a new theory for the origin of dark matter, helping experimentalists in Australia and abroad in the search for the mysterious new matter.

The work has been published in Physical Review Letters and describes how expanding bubbles in the early universe may be the key to understanding dark matter.

“Our proposed mechanism suggests that the dark matter abundance may have been determined in a cosmological phase transition,” said Dr. Michael Baker, a postdoctoral research fellow at the University of Melbourne and one of the authors.

Why are galaxies different shapes?

Look into the night sky and you’ll glimpse the stars from hundreds of billions of galaxies. Some galaxies are swirling blue disks like our own Milky Way, others are red spheres or misshapen, clumpy messes or something in between. Why the different configurations? It turns out that a galaxy’s shape tells us something about the events in that galaxy’s ultra-long life.

At the very basic level there are two classifications for galaxy shapes: disk and elliptical. A disk galaxy, also called a spiral galaxy, is shaped like a fried egg, said Cameron Hummels, theoretical astrophysicist at Caltech. These galaxies have a more spherical center, like the yolk, surrounded by a disk of gas and stars — the egg white. The Milky Way and our nearest galaxy neighbor Andromeda fall into this category.

RHIC Collider Creates Quark-Gluon Plasma at 4,000,000,000,000 Degrees Celsius

Circa 2010

Until the LHC finally gets up to full speed, Brookhaven National Lab’s Relativistic Heavy Ion Collider (RHIC) remains the world’s most powerful heavy ion smasher. And on Monday, they showed off some of that power by announcing that a recent collision resulted in the hottest matter ever recorded. Coming in at a scorching 7.2 trillion degrees Fahrenheit, the plasma not only recreated the environment of the Big Bang, but might have also resulted in the temporary formation of a bubble within which some normal laws of physics did not apply.

The 2020 Nobel Prize in physics awarded for work on black holes. An astrophysicist explains the trailblazing discoveries

Black holes are perhaps the most mysterious objects in nature. They warp space and time in extreme ways and contain a mathematical impossibility, a singularity – an infinitely hot and dense object within. But if black holes exist and are truly black, how exactly would we ever be able to make an observation?

This morning the Nobel Committee announced that the 2020 Nobel Prize in physics will be awarded to three scientists – Sir Roger Penrose, Reinhard Genzel and Andrea Ghez – who helped discover the answers to such profound questions. Andrea Ghez is only the fourth woman to win the Nobel Prize in physics.

Robert Penrose is a theoretical physicist who works on black holes, and his work has influenced not just me but my entire generation through his series of popular books that are loaded with his exquisite hand-drawn illustrations of deep physical concepts.