Each February APS News looks back to see what physics news stories grabbed the most headlines in the previous year. The list is a compilation of not necessarily the most “important” advancements of the year, but the stories that captured the attention and interest of the world. In roughly chronological order, the Top Physics Newsmakers of 2012 are:
2012 was a big year for the discovery of planets outside of our solar system, and many scientists believe that the discovery of a potentially habitable planet like Earth is not far away. January brought the announcement of the discovery of a system of planets around the star Kepler-42 with planets similar in size to Venus and Mars, the smallest discovered yet. In February, astronomers announced the discovery of Gliese 667Cc only 22 light years away, the first planet discovered inside of a star’s habitable zone. The discovery of Alpha Centauri Bb, a planet orbiting the star closest to Earth, was announced in October, hinting that planets might be very common around stars. In December the five-planet system around Tau Ceti was discovered, which included two planets far enough away from their parent star that liquid water could exist on their surface.
In February, physicists from Delft University found evidence of Majorana fermions, particles that are their own anti-particles, in the behavior of electrons in a semiconducting nanowire. The team did not observe the particles directly, but they were able to infer hints of their existence by detecting minute electrical currents that matched predictions. Scientists are excited because such particles could form the basis for a future quantum computer. Fermions that are their own antiparticles were first predicted by Ettore Majorana in 1937, just months before his mysterious disappearance at sea.
The international Daya Bay Reactor Neutrino Experiment, announced in March the successful measurement of the neutrino mixing angle θ13. Six detectors measured the neutrinos emitted by China’s Daya Bay nuclear reactors, looking for differences in the number of electron antineutrinos detected. Neutrinos oscillate between different flavors, and θ13, the parameter that governs the rate at which electron neutrinos morph into other flavors, was the last to be measured. The collaboration found the angle was relatively large, making it easier for physicists to investigate the origin of matter-antimatter asymmetry in the universe.
The “Pioneer anomaly” has vexed physicists since it was first noticed in the early 1980s. The two Pioneer probes, numbers 10 and 11, have been inexplicably slowing down more than expected on their way towards interstellar space. Numerous explanations have been put forward, ranging from leaking gas to a fundamental reworking of general relativity, but in April, an analysis by Slava Turyshev published in Physical Review Letters finally determined once and for all that pressure from uneven thermal radiation has been the culprit for all of these years.
In April Dmitri Krioukov argued his way out of a traffic ticket using physics. In a paper published on the ArXiv, Krioukov claimed that a confluence of coincidences, including his sudden deceleration and acceleration, an optical illusion making objects farther away seem to be moving faster, and an obstructing car made it appear that he drove through a stop sign, when in fact he had stopped. The judge seemed to agree and rescinded the traffic offense.
In May, the two most recently discovered elements were given names after the physics labs that discovered them. Number 114 is flerovium (Fl) after the Flerov Laboratory of Nuclear Reactions in Dubna, Russia, and number 116 is livermorium (Lv) after the Lawrence Livermore National Laboratory in Livermore, California. In September researchers at the RIKEN laboratory in Japan claimed to have successfully generated atoms of element 113. If confirmed, it would be the first new element to be discovered in East Asia, though researchers in the US and Russia have also claimed to have synthesized the element in the past.
The title of the “World’s Fastest Computer” returned to the United States this June when Lawrence Livermore National Laboratory’s Sequoia machine topped out at 16.2 petaflops. Then in November, Oak Ridge National Laboratory one-upped them with its Titan supercomputer, which hit 17.59 petaflops. US computers now hold the top two slots for the first time since 2009, beating out Japan’s K computer. Sequoia is used by the military to simulate nuclear detonations while Titan is an open machine leasable by the public.
Teams on opposite sides of the globe have been duking it out to hold the title of the farthest distance two quantum particles can be kept in an entangled state. In May a team in China shattered the existing record by teleporting a photon 97 kilometers, nearly 100 times the existing record. In September a team from Austria working in the Canary Islands was able to teleport a pair of photons 147 kilometers, between two islands, hoping to pave the way to teleport a pair between an orbiting satellite and the planet’s surface sometime in the future.
On the 4th of July, CERN announced that it had found what appeared to be the long sought-after Higgs boson. The laboratory was guarded in its original announcement, saying only that they had found a boson with Higgs-like properties. The accomplishment caps decades of work and billions of dollars building the Large Hadron Collider. The discovery confirms the existence of a “Higgs field” that gives matter its mass, first proposed almost 50 years ago.
New Physics Prize
Russian billionaire Yuri Milner is giving the Nobel Prizes a run for their money with his announcement in July of the new Fundamental Physics Prize. Each of the nine inaugural winners, primarily theoretical physicists in cosmology, mathematics and string theory, received $3 million. Milner personally chose the first round, but past recipients will in part choose future winners of the new annual award. In December, Milner made two special awards, one to Stephen Hawking, and another to be shared amongst top scientists at CERN for discovering the Higgs Boson.
Researchers in England announced in August that they were able to build the first solid-state maser that works at room temperature. The very first masers were built in 1954 but were weak and required extremely low temperatures to operate. Soon thereafter, the first solid-state masers were built, which offered more power, but still required near zero temperatures to operate. The team from Imperial College in London developed a completely new technique to create a collimated beam of microwaves using p-terphenyl as a gain medium rather than traditional crystalline ruby.
In September, the National Snow and Ice Data Center announced that 2012 broke the record set in 2007 for the lowest amount of sea ice ever. Ice only covered 1.32 million square miles of the arctic, 18 percent below the 2007 record, and 49 percent below the 1979 through 2000 average. Climatologists pointed to this as more evidence that climate change is a major concern and that rising global temperatures are having an impact on the environment.
Physicists had to make two major retractions this year. In February CERN announced that the controversial claim a year before, that neutrinos appeared to travel faster than the speed of light, was likely the result of a loose cable. Two months later, the lead scientist of the team that made the announcement stepped down. In October, Moses Chan officially retracted his 2004 announcement of the discovery of supersolids. In an experiment designed to eliminate a source of error first identified in 2007, Chan was unable to recreate the effects observed in his first experiments, and subsequently published his new results in Physical Review Letters.
Throughout the year, the news has been dominated by headlines about water being found in unexpected places throughout the solar system. In June an article in Science said that the Cassini spacecraft found evidence of a liquid ocean of water deep under the icy shell of Saturn’s moon Titan. In September, scientists announced that NASA’s Curiosity rover found beds of rounded pebbles, evidence that water likely once flowed in deep streams across the surface of Mars. Also in September, scientists announced that they unexpectedly found water on the asteroid Vesta. Rounding out a year of soggy discoveries in November, NASA’s Messenger spacecraft found evidence of frozen water underneath the surface of the closest planet to the sun, Mercury.
–list compiled by Michael Lucibella
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Staff Science Writer: Michael Lucibella