Graphene’s properties make it a tantalizing target for semiconductor research. Now a team from Princeton has showed that flakes of graphene can work as fast, accurate optical capacitors for laser transistors in neuromorphic circuits.
Although we experience time in one direction—we all get older, we have records of the past but not the future—there’s nothing in the laws of physics that insists time must move forward.
In trying to solve the puzzle of why time moves in a certain direction, many physicists have settled on entropy, the level of molecular disorder in a system, which continually increases. But two separate groups of prominent physicists are working on models that examine the initial conditions that might have created the arrow of time, and both seem to show time moving in two different directions.
When the Big Bang created our universe, these physicists believe it also created an inverse mirror universe where time moves in the opposite direction. From our perspective, time in the parallel universe moves backward. But anyone in the parallel universe would perceive our universe’s time as moving backward.
Asteroid mining and space tourism are all well and good, but a network of researchers around the world is thinking bigger when it comes to space exploration: interstellar travel.
The astrophysics project Space Warps offers a compelling example of why citizen science has become such a popular tool and how valuable it can be. In a roundtable discussion with the Kavli Foundation, citizen science leaders and astrophysicists Chris Lintott, Anupreeta More and Aprajita Verma discuss the tremendous impact these enthusiastic volunteers are having.
A new theory from physicists at the U.S. Department of Energy’s Brookhaven National Laboratory, Fermi National Accelerator Laboratory, and Stony Brook University, which will publish online on January 18 in Physical Review Letters, suggests a shorter secondary inflationary period that could account for the amount of dark matter estimated to exist throughout the cosmos.
“In general, a fundamental theory of nature can explain certain phenomena, but it may not always end up giving you the right amount of dark matter,” said Hooman Davoudiasl, group leader in the High-Energy Theory Group at Brookhaven National Laboratory and an author on the paper. “If you come up with too little dark matter, you can suggest another source, but having too much is a problem.”
Measuring the amount of dark matter in the universe is no easy task. It is dark after all, so it doesn’t interact in any significant way with ordinary matter. Nonetheless, gravitational effects of dark matter give scientists a good idea of how much of it is out there. The best estimates indicate that it makes up about a quarter of the mass-energy budget of the universe, while ordinary matter — which makes up the stars, our planet, and us — comprises just 5 percent. Dark matter is the dominant form of substance in the universe, which leads physicists to devise theories and experiments to explore its properties and understand how it originated.
An international team of astrophysicists has discovered the brightest supernova yet, briefly blazing fifty times brighter than the entire Milky Way galaxy. It’s a strange new way for stars to die.
As described in a new paper in Science, this spectacularly extravagant stellar explosion— part of a classification known as super luminous supernovae —may give us a peek into the death of stars from near the beginning of the Universe, helping unravel the secrets of early stellar evolution. It’s been named ASAS-SN-15lh.
Humans have been spotting the suddenly-bright pinpricks of stars violently exploding in the night sky for thousands of years, with some records even telling of the rapid appearance and disappearance of stars so bright they can be seen by the naked eye even during in the day. Superluminous supernova kick it up a notch, shining a hundred to a thousand times brighter than a normal nova.
Max Tegmark about his and others’ attempts to formulate a mathematical theory of consciousness. I find this very interesting, though I try to not think about it too much… I wrote some words about this here http://backreaction.blogspot.com/2014/05/consciousness-and-p…ratch.html
Barely a week later, cosmologist Lawrence Krauss at Arizona State University tweeted a rumour that the detector had already picked up a signal.
Now Krauss claims that the original rumour has been confirmed by an independent source.
Barely a week later, cosmologist Lawrence Krauss at Arizona State University tweeted a rumour that the detector had already picked up a signal.
Continue reading “New rumours that gravitational waves have finally been detected” »
Excited rumors began circulating on Twitter this morning that a major experiment designed to hunt for gravitational waves —ripples in the fabric of spacetime first predicted by Albert Einstein—has observed them directly for the very first time. If confirmed, this would be one of the most significant physics discoveries of the last century.
Move a large mass very suddenly—or have two massive objects suddenly collide, or a supernova explode—and you would create ripples in space-time, much like tossing a stone in a still pond. The more massive the object, the more it will churn the surrounding spacetime, and the stronger the gravitational waves it should produce. Einstein predicted their existence in his general theory of relativity back in 1915, but he thought it would never be possible to test that prediction.
LIGO (Laser Interferometer Gravitational Wave Observatory) is one of several experiments designed to hunt for these elusive ripples, and with its latest upgrade to Advanced LIGO, completed last year, it has the best chance of doing so. In fact, it topped our list of physics stories to watch in 2016.
At present, scientists study gravitational fields passively. They observe and try to understand existing gravitational fields produced by large inertial masses, such as stars or Earth, without being able to change them as is done, for example, with magnetic fields.
This led Andre Fuzfa from Namur University in Belgium to attempt a revolutionary approach — creating gravitational fields at will from well-controlled magnetic fields and observing how these magnetic fields could bend space-time.
In his study, Fuzfa has proposed, with supporting mathematical proof, a device with which to create detectable gravitational fields.
