Circa 2020
Like watching a movie in reverse, physicists have just demonstrated a new technique for the time-reversal of a wave of optical light.
Continue reading “Physicists Create Time-Reversed Waves of Optical Light in Head-Spinning First” »
Thu, Sep 30 at 4 PM PDT.
Black holes are cosmic objects so small and dense that nothing, not even light, can escape their gravitational pull. Until recently, no one had ever seen what a black hole actually looked like. Einstein’s theories predict that a distant observer should see a ring of light encircling the black hole, which forms when radiation emitted by infalling hot gas is lensed by the extreme gravity near the event horizon. The Event Horizon Telescope (EHT) is a global array of radio dishes, linked together by a network of atomic clocks to form an Earth-sized virtual telescope that can resolve the nearest supermassive black holes where this ring feature may be measured. On April 10th, 2,019 the EHT project reported success: we imaged a black hole, and saw the predicted strong gravitational lensing that confirms the theory of General Relativity at the boundary of a black hole. This talk will cover how this was accomplished, details of the first results, as well as future directions that will enable real-time black hole movies.
About Dr. Shep Doeleman:
Multiverse Cosmology, Nobel Laureates, Theories Of Everything, And Much More! — Dr. Brian Keating Ph.D., Chancellor’s Distinguished Professor of Physics, UC San Diego.
Dr. Brian Keating, Ph.D. (https://briankeating.com/) is Chancellor’s Distinguished Professor of Physics, at the Center for Astrophysics & Space Sciences (CASS), in the Department of Physics, at the University of California, San Diego (https://bkeating.physics.ucsd.edu/).
Circa 2012
Faraday and Dirac constructed magnetic monopoles using the practical and mathematical tools available to them. Now physicists have engineered effective monopoles by combining modern optics with nanotechnology. Part matter and part light, these magnetic monopoles travel at unprecedented speeds.
In classical physics (as every student should know) there are no sources or sinks of magnetic field, and hence no magnetic monopoles. Even so, a tight bundle of magnetic flux — such as that created by a long string of magnetic dipoles — has an apparent source or sink at its end. If we map the lines of force with a plotting compass, we think we see a magnetic monopole as our compass cannot enter the region of dense flux. In 1,821 Michael Faraday constructed an effective monopole of this sort by floating a long thin bar magnet upright in a bowl of mercury, with the lower end tethered and the upper end free to move like a monopole in the horizontal plane.
A surprise result for solid state physicists hints at an unusual electron behavior.
While studying the behavior of electrons in iron-based superconducting materials, researchers at the University of Tokyo observed a strange signal relating to the way electrons are arranged. The signal implies a new arrangement of electrons the researchers call a nematicity wave, and they hope to collaborate with theoretical physicists to better understand it. The nematicity wave could help researchers understand the way electrons interact with each other in superconductors.
A long-standing dream of solid state physicists is to fully understand the phenomenon of superconductivity — essentially electronic conduction without the resistance that creates heat and drains power. It would usher in a whole new world of incredibly efficient or powerful devices and is already being used on Japan’s experimental magnetic levitation bullet train. But there is much to explore in this complex topic, and it often surprises researchers with unexpected results and observations.
Stellarators, twisty magnetic devices that aim to harness on Earth the fusion energy that powers the sun and stars, have long played second fiddle to more widely used doughnut-shaped facilities known as tokamaks. The complex twisted stellarator magnets have been difficult to design and have previously allowed greater leakage of the superhigh heat from fusion reactions.
Now scientists at the Max Planck Institute for Plasma Physics (IPP), working in collaboration with researchers that include the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL
The U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) is a collaborative national laboratory for plasma physics and nuclear fusion science. Its primary mission is research into and development of fusion as an energy source for the world.
Black holes are getting weirder by the day. When scientists first confirmed the behemoths existed back in the 1970s, we thought they were pretty simple, inert corpses. Then, famed physicist Stephen Hawking discovered that black holes aren’t exactly black and they actually emit heat. And now, a pair of physicists has realized that the sort-of-dark objects also exert a pressure on their surroundings.
The finding that such simple, non-rotating “black holes have a pressure as well as a temperature is even more exciting given that it was a total surprise,” co-author Xavier Calmet, a professor of physics at the University of Sussex in England, said in a statement.
A new paper takes a deep dive into primordial black holes that were formed as a part of the early universe when there were still no stars or galaxies. Such black holes could account for strange cosmic possibilities, including baby universes and major features of the current state of the cosmos like dark matter.
To study the exotic primordial black holes (PBHs), physicists employed the Hyper Suprime-Cam (HSC) of the huge 8.2m Subaru Telescope operating near the 4,200 meter summit of Mt. Mauna Kea in Hawaii. This enormous digital camera can produce images of the entire Andromeda galaxy every few minutes, helping scientists observe one hundred million stars in one go.
Solving the mystery of how and why fireflies flash in time can illuminate the physics of complex systems by Orit Peleg + BIO.
A team of physicists at CU Boulder has solved the mystery behind a perplexing phenomenon in the nano realm: why some ultra-small heat sources cool down faster if you pack them closer together. The findings, published today in the journal Proceedings of the National Academy of Sciences (PNAS), could one day help the tech industry design faster electronic devices that overheat less.
“Often, heat is a challenging consideration in designing electronics. You build a device then discover that it’s heating up faster than desired,” said study co-author Joshua Knobloch, postdoctoral research associate at JILA, a joint research institute between CU Boulder and the National Institute of Standards and Technology (NIST). “Our goal is to understand the fundamental physics involved so we can engineer future devices to efficiently manage the flow of heat.”
The research began with an unexplained observation: In 2,015 researchers led by physicists Margaret Murnane and Henry Kapteyn at JILA were experimenting with bars of metal that were many times thinner than the width of a human hair on a silicon base. When they heated those bars up with a laser, something strange occurred.
