Einstein’s framework for the universe, space-time, is at odds with quantum theory. Overcoming this clash and others is vital to unravelling the true nature of the cosmos.
Researchers at the University of Illinois at Urbana-Champaign have replicated one of the most well-known electromagnetic effects in physics, the Hall Effect, using radio waves (photons) instead of electric current (electrons). Their technique could be used to create advanced communication systems that boost signal transmission in one direction while simultaneously absorbing signals going in the opposite direction.
The Hall Effect, discovered in 1879 by Edwin Hall, occurs because of the interaction between charged particles and electromagnetic fields. In an electric field, negatively charged particles (electrons) experience a force opposite to the direction of the field. In a magnetic field, moving electrons experience a force in the direction perpendicular to both their motion and the magnetic field. These two forces combine in the Hall Effect, where perpendicular electric and magnetic fields combine to generate an electric current. Light isn’t charged, so regular electric and magnetic fields can’t be used to generate an analogous “current of light.” However, in a recent paper published in Physical Review Letters, researchers have done exactly this with the help of what they call “synthetic electric and magnetic fields.”
Principal investigator Gaurav Bahl’s research group has been working on several methods to improve radio and optical data transmission as well as fiber optic communication. Earlier this year, the group exploited an interaction between light and sound waves to suppress the scattering of light from material defects and published its results in Optica. In 2018, team member Christopher Peterson was the lead author in a Science Advances paper which explained a technology that promises to halve the bandwidth needed for communications by allowing an antenna to send and receive signals on the same frequency simultaneously through a process called nonreciprocal coupling.
Industry and military scientists are moving forward in the quest to develop solid-state lasers for use as weapons by warfighters of the future
By John McHale
Even the most casual observer of military technology is aware of the U.S. Air Force’s big-ticket program-the Airborne Laser, which eats up most of the Department of Defense funding on laser technology and is nearing completion.
The world’s biggest astrophotography competition includes some jaw-dropping images of the Moon, Sun, distant galaxies and much more.
Einstein dubbed the idea of quantum entanglement as “spooky action at a distance.” Now for the first time ever, scientists have taken a picture of it.
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Today we understand quantum entanglement as when a pair of particles that cross paths and interact with each other can become connected and stay that way, even when the particles are spaced very far apart.
The current menu of space-friendly foods uses processing and water-reduction strategies to make these meals shelf stable. For example, a shrimp cocktail, mashed potatoes, and strawberries can be freeze dried; beef stew, candied yams, and brown rice can be thermostabilized; beef steak and turkey can be irradiated; and brownies, bread products, and beverage powders can be brought up in a low-moisture or dried form.
As tasty as this feast sounds, this packaged food system does not meet the five-year shelf life required for a Mars mission, nor will it feed generations there in the years to come. How will space food therefore have to change if we are ever to colonize other planets?
Using existing space technologies, it will take up to 32 months to travel to Mars. How can you feed a crew for that three-year trip?
The universe is looking younger every day, it seems.
New calculations suggest the universe could be a couple billion years younger than scientists now estimate, and even younger than suggested by two other calculations published this year that trimmed hundreds of millions of years from the age of the cosmos.
The huge swings in scientists’ estimates—even this new calculation could be off by billions of years—reflect different approaches to the tricky problem of figuring the universe’s real age.
