Surprise in solid-state physics: The Hall effect, which normally requires magnetic fields, can also be generated in a completely different way – with extreme strength.
Electric current is deflected by a magnetic field – in conducting materials this leads to the so-called Hall effect. This effect is often used to measure magnetic fields. A surprising discovery has now been made at TU Wien, in collaboration with scientists from the Paul Scherrer Institute (Switzerland), McMater University (Canada), and Rice University (USA): an exotic metal made of cerium, bismuth, and palladium was examined and a giant Hall effect was found to be produced by the material, in the total absence of any magnetic field. The reason for this unexpected result lies in the unusual properties of the electrons: They behave as if magnetic monopoles were present in the material. These discoveries have now been published in the scientific magazine PNAS.
Bronstein’s paper highlighted how research in many scientific fields such as computational social science, sensors network, physics, and healthcare calls for exploring non-Euclidean data.
Every day space telescopes provide spectacular images of the solar activity. However, their instruments are blind to its main driver: the magnetic field in the outer layers of the solar atmosphere, where the explosive events that occasionally affect the Earth occur. The extraordinary observations of the polarization of the Sun’s ultraviolet light achieved by the CLASP2 mission have made it possible to map the magnetic field throughout the entire solar atmosphere, from the photosphere until the base of the extremely hot corona. This investigation, published today in the journal Science Advances, has been carried out by the international team responsible for this suborbital experiment, which includes several scientists of the POLMAG group of the Instituto de Astrofísica de Canarias (IAC).
The chromosphere is a very important region of the solar atmosphere spanning a few thousand kilometers between the relatively thin and cool photosphere (with temperatures of a few thousand degrees) and the hot and extended corona (with temperatures above a million degrees). Although the temperature of the chromosphere is about one hundred times lower than that of the corona, the chromosphere has a far higher density, and thus much more energy is required to sustain it. Moreover, the mechanical energy necessary to heat the corona needs to traverse the chromosphere, making it a crucial interface region for the solution of many of the key problems in solar and stellar physics. One of the current scientific challenges is to understand the origin of the violent activity of the solar atmosphere, which on some occasions perturb the Earth’s magnetosphere with serious consequences for our present technological world.
Physicists from the University of Sussex have created what they called the tiniest microchips yet. The little microchips are made using graphene and other 2D materials and a form of “nano-origami.” The technique used in creating the tiny microchips marks the first time any researchers have been able to do this.
Researchers succeeded in making the tiny microchips by creating kinks in the structure of graphene to make the nanomaterial behave like a transistor. In their study, the team showed that when a graphene strip is crinkled in a specific way, it behaves like a microchip only about 100 times smaller than a conventional microchip. New construction methods are needed for microchips because traditional semiconducting technology is at the limit of what it can do.
The researchers believe that using the materials in their technique will make computer chips smaller and faster. The technology is dubbed “straintronics” and uses nanomaterials rather than electronics, allowing space for more chips inside a given device. The researchers believe everything we want to do with computers to speeding them up can be done by crinkling graphene.
New observations of the first black hole ever detected have led astronomers to question what they know about the Universe’s most mysterious objects.
Published today (February 182021) in the journal Science, the research shows the system known as Cygnus X-1 contains the most massive stellar-mass black hole ever detected without the use of gravitational waves.
Cygnus X-1 is one of the closest black holes to Earth. It was discovered in 1964 when a pair of Geiger counters were carried on board a sub-orbital rocket launched from New Mexico.
It’s a fundamental law of physics that even the most ardent science-phobe can define: matter falls down under gravity. But what about antimatter, which has the same mass but opposite electrical charge and spin? According to Einstein’s general theory of relativity, gravity should treat matter and antimatter identically. Finding even the slightest difference in their free-fall rate would therefore lead to a revolution in our understanding. While the free fall of matter has been measured with an accuracy of around one part in 100 trillion, no direct measurement for antimatter has yet been performed due to the difficulty in producing and containing large quantities of it.
A novel computer algorithm, or set of rules, that accurately predicts the orbits of planets in the solar system could be adapted to better predict and control the behavior of the plasma that fuels fusion facilities designed to harvest on Earth the fusion energy that powers the sun and stars.
The algorithm, devised by a scientist at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL), applies machine learning, the form of artificial intelligence (AI) that learns from experience, to develop the predictions. “Usually in physics, you make observations, create a theory based on those observations, and then use that theory to predict new observations,” said PPPL physicist Hong Qin, author of a paper detailing the concept in Scientific Reports. “What I’m doing is replacing this process with a type of black box that can produce accurate predictions without using a traditional theory or law.”
Qin (pronounced Chin) created a computer program into which he fed data from past observations of the orbits of Mercury, Venus, Earth, Mars, Jupiter, and the dwarf planet Ceres. This program, along with an additional program known as a “serving algorithm,” then made accurate predictions of the orbits of other planets in the solar system without using Newton’s laws of motion and gravitation. “Essentially, I bypassed all the fundamental ingredients of physics. I go directly from data to data,” Qin said. “There is no law of physics in the middle.”
Chair emeritus, SETI institute — the search for extraterrestrial intelligence.
Dr. Jill Tarter is Chair Emeritus for SETI (Search for Extraterrestrial Intelligence) Research at the SETI Institute, a not-for-profit research organization whose mission is to explore, understand, and explain the origin and nature of life in the universe, and to apply the knowledge gained to inspire and guide present and future generations.
Dr. Tarter received her Bachelor of Engineering Physics Degree with Distinction from Cornell University and her Master’s Degree and a Ph.D. in Astronomy from the University of California, Berkeley. She served as Project Scientist for NASA’s SETI program, the High Resolution Microwave Survey, and has conducted numerous observational programs at radio observatories worldwide. Since the termination of funding for NASA’s SETI program in 1993, she has served in a leadership role to secure private funding to continue the exploratory science. Currently, she serves on the management board for the Allen Telescope Array, an innovative array of 350 (when fully realized) 6-m antennas at the Hat Creek Radio Observatory, it will simultaneously survey the radio universe for known and unexpected sources of astrophysical emissions, and speed up the search for radio emissions from other distant technologies by orders of magnitude.
Dr. Tarter’s work has brought her wide recognition in the scientific community, including the Lifetime Achievement Award from Women in Aerospace, two Public Service Medals from NASA, Chabot Observatory’s Person of the Year award (1997), Women of Achievement Award in the Science and Technology category by the Women’s Fund and the San Jose Mercury News (1998), and the Tesla Award of Technology at the Telluride Tech Festival (2001). She was elected an AAAS Fellow in 2002 and a California Academy of Sciences Fellow in 2003. In 2004 Time Magazine named her one of the Time 100 most influential people in the world, and in 2005 Dr. Tarter was awarded the Carl Sagan Prize for Science Popularization at Wonderfest, the biannual San Francisco Bay Area Festival of Science.
Dr. Tarter is deeply involved in the education of future citizens and scientists. In addition to her scientific leadership at NASA and SETI Institute, Dr. Tarter was the Principal Investigator for two curriculum development projects funded by NSF, NASA, and others. The first, the Life in the Universe series, created 6 science teaching guides for grades 3–9 (published 1994–96). Her second project, Voyages Through Time, is an integrated high school science curriculum on the fundamental theme of evolution in six modules: Cosmic Evolution, Planetary Evolution, Origin of Life, Evolution of Life, Hominid Evolution and Evolution of Technology (published 2003).
