With the help of highly sensitive particle detectors, some of the world’s most powerful lasers, and good-old-fashioned quantum mechanics, physicists from around the world made important discoveries this year.
From detecting elusive particles forged in the core of our sun to teleporting quantum data farther than ever before, these physicists’ scientific research has helped us better understand the universe in which we live as well as pave the way for a future of quantum computers, nuclear fusion, and more.
Although dark matter -- the mysterious substance that makes up most of the matter in the universe, but is seemingly undetectable to us here on Earth -- is still shrouded in mystery, two important discoveries in 2014 shed the first rays of light on this elusive material.
Dark matter makes up 26.8% of our universe, and to know so little about such a large portion of the cosmos is why these studies to better understand this elusive material are so important.
In September 2014, scientists published, in the journal Physical Review Letters, an unusual measurement from the space-based detector called the Alpha Magnetic Spectrometer (AMS). The detector measured an unexpected excess of positrons -- the antiparticle to electrons -- inside of high-energy radiation from space called cosmic rays. One explanation for this excess is the decay of dark matter.
Then, a few months later, a team of scientists discovered another possible source of dark matter. Using the European Space Agency's XMM-Newton spacecraft and NASA's space-based Chandra X-ray Observatory, two groups of scientists measured a surprising spike in X-ray emissions that were coming from the Andromeda galaxy and the Perseus galaxy cluster. No known particle can explain this spike, leading the scientists to suspect more mysterious causes, one being dark matter, which they report in the journal Physical Review Letters.
Despite neither of these surprising measurements actually confirming the detection of dark matter, they are an important step in nailing down, once and for all, what our universe is made of.
10. For the first time, physicists figured out the chemical composition of the mysterious and extremely rare phenomenon of 'ball lightning.'
Reports of ball lighting stretch back as far as the 16th century, but until the 1960s most scientists refused to believe it was real. But, it is real. Ball lighting is a floating sphere or disk of lightning up to 10 feet across that lasts only seconds.
This year, however, scientists in China not only added to the surmounting evidence supporting ball lightning's existence, they also took the first spectrum of the rare phenomenon. A spectrum is the rainbow of individual wavelengths of light from a given source, and is used to figure out its chemical make up because different atoms give off different energies (and therefore colours) of light when excited.
In the ball lightnings' spectra, the physicists saw minerals from soil, which supports the theory that ball lightning forms after a bolt of lighting strikes the ground. The lightning vaporizes the silicon in the soil, making a floating ball of silicon that interacts with oxygen in the air, making it glow.
The physicists announced their discovery last January in the journal Physical Review Letters.
Last October, Jeff Steinhauer, a physicist at the Technion-Israel Institute of Technology in Haifa, announced that he had created an analogue for a bizarre type of radiation that can, in theory, escape black holes.
Black holes are objects that have a strong gravitational pull, so once anything passes a certain point, called the event horizon, it is trapped and cannot escape, except for a special kind of radiation called Hawking radiation.
While it has never been observed in space, it was first theorized by Stephen Hawking in 1974. Hawking radiation is important to describe how particles of radiation near the event horizon of a black hole can move from inside of the black hole to outside of it -- a behaviour that is theoretically possible, according to quantum mechanics.
Steinhauer created a sonic black hole in the lab that traps sound instead of light. This is much easier because sound moves much slower than light.
In a paper published in October in the journal Nature Physics, he describes how he discovered sound waves hopping the 'black hole's' event horizon.
This analogue to Hawking radiation could help solve a burning question for physicists who study black holes: If a piece of radiation is encoded with information, like the spin value of particles, and falls into a black hole, is that information lost forever?
During a supernova, a star explodes, ejecting its guts across space and leaving only a ghostly halo of gas and dust, called a supernova remnant, behind. Astrophysicists have observed supernovae remnants of all shapes and sizes but have yet to understand why they are all so different.
So, a team of international physicists used one of the world's most powerful laser facilities, the Vulcan laser facility in the UK, to recreate this astronomical event. Three laser beams focused on a carbon-rod as thick as a human hair and heated it to about 5.4 million degrees Fahrenheit at which point the rod exploded. The explosion, they said, mimicked a supernova in space.
In some of the experiments, they placed a small plastic grid (which would resemble a clump of gas or dust in space) near the rod that then disturbed the flow of gas from the explosion's shock wave. The result, they discovered, was irregular features that might explain the variety of irregularly-shaped supernova remnants. They published their findings last June in the journal Nature Physics.
5. Researchers transferred information in light four times farther than ever before -- an important step to quantum computers.
If we are ever to have a digital world run by quantum computers, then we must learn how to transport information in the form of what scientists call quantum data, or qubits, which is encoded inside of subatomic particles, such as ions or photons (light particles).
Last September, a team of physicists in Switzerland broke the record for the longest distance anyone had ever teleported an information-encoded photon, to a piece of matter, a crystal, without losing the information. The physicists successfully teleported the photon 15.5 miles -- 4 times longer than the record the team had set in 2003 -- and reported their discovery in the journal Nature Photonics.
Traditionally, when you're trying to transfer particles of light through a fibre optic cable, the last thing you want are for the particles to be moving all about in a disorderly manner. But there's an exception to this that scientists at the University of Wisconsin-Milwaukee and Clemson University discovered the first time this year.
The team showed that if you put the right kind of disorder in just the right place, then you can actually enhance the image that a fibre optic cable produces. The lead author of the paper, which the team published in the journal Nature Communications last March, told Physics World that the advantage of these new optical fibres is that, because of the Anderson localisation effect, they offer higher resolution images than conventional fibre bundles.
After nearly 80 years since it was first predicted, the Majorana fermion was finally observed. The physicists at Princeton University and the University of Texas at Austin announced their discovery last October in the journal Science.
Majorana fermions rarely interact with their environment, which makes them difficult to detect and observe. On the upside, their elusive quality makes them an attractive candidate for future tests involving the teleportation of quantum data.
Energy from the sun is essential for life on Earth. Yet we were not certain of how the sun's core works until just this year.
Last August, a team of physicists of the Borexino experiment announced, in the journal Nature, that they had observed a particularly elusive type of subatomic particle called a neutrino that scientists have suspected for years is produced deep within our sun's core as the result of nuclear fusion.
The Borexino experiment is a large, spherically-shaped detector in Italy that has been searching for low-energy neutrinos, which are created by a nuclear fusion reaction called the proton-proton chain. This reaction was first proposed in the 1920s to fuel stars the size of our sun and smaller -- and finding these neutrinos would confirm this theory.
Theory predicted that, through this fusion process, the sun would fling approximately 60 billion of these low-energy neutrinos through one square-centimeter of Earth each second. And physicists working on the Borexino experiment reported to observe about 66 billion, indicating that what scientists have been saying about the sun's source of energy is correct.
The most important physics discovery of 2014 later became the most highly-hyped measurement error in physics of 2014.
Of course, this is referring to the results collected by a highly sensitive telescope based in Antarctica, called BICEP2 that researchers claimed were the first detection of a cosmic phenomenon called gravitational waves. If the discovery had held true, it would have been a new way to study the farthest reaches of space and would have also added to the surmounting evidence supporting Einstein's theory of relativity. But it wasn't meant to be. To understand what went wrong, here's a little background first:
Whenever any object in space accelerates, it creates ripples in the universal fabric of space time, just like ripples in a pond. These ripples, called gravitational waves, propagate through space and are usually extremely small -- far too small to detect on Earth. Only the most massive objects with the largest accelerations can produce anything we could hope to detect. The collision between two supermassive black holes is one example. Another is the most massive explosion in the history of our universe besides the Big Bang, known as inflation.
Less than a second after the Big Bang, the universe expanded by as much as 10 trillion trillion trillion times, and this expansion, referred to as inflation, generated a lot of gravitational waves. The BICEP2 team said they had observed, for the first time, a signature that they linked directly to gravitational waves from inflation.
The problem was that this signal could also be linked to cosmic dust. It sounds simple, but it's anything but. To boil it down, BICEP2 measured a kind of polarised light, which is light that has been separated into a specific energy group. You polarize sunlight every time you put on sunglasses because the sunglasses only letting the less energetic, a.k.a. darker, light to reach your eyeballs.
Inflation also polarised light. But so does dust. And it turns out that in September, a different team of researchers showed that the BICEP2 team's results could, in large part, be explained by dust polarization. The BICEP2 team still published their results in the journal Physical Review Letters. But after an extensive peer review process, they reduced the certainty of their measurements and claims. Now teams from BICEP2 and Planck are working together to further analyse the data to determine, once and for all, if this is a discovery for the history books.
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