On a cold winter day, the warmth of the sun is welcome. Yet as humanity emits more and more greenhouse gases, the Earth’s atmosphere traps more and more of the sun’s energy and steadily increases the Earth’s temperature. One strategy for reversing this trend is to intercept a fraction of sunlight before it reaches our planet. For decades, scientists have considered using screens, objects or dust particles to block just enough of the sun’s radiation—between 1 or 2%—to mitigate the effects of global warming.
A University of Utah-led study explored the potential of using dust to shield sunlight. They analyzed different properties of dust particles, quantities of dust and the orbits that would be best suited for shading Earth. The authors found that launching dust from Earth to a way station at the “Lagrange Point” between Earth and the sun (L1) would be most effective but would require astronomical cost and effort. An alternative is to use moondust. The authors argue that launching lunar dust from the moon instead could be a cheap and effective way to shade the Earth.
The team of astronomers applied a technique used to study planet formation around distant stars, their usual research focus. Planet formation is a messy process that kicks up lots of astronomical dust that can form rings around the host star. These rings intercept light from the central star and re-radiate it in a way that we can detect it on Earth. One way to discover stars that are forming new planets is to look for these dusty rings.
This February sees the launch of Collision: Stories from the science of CERN, the culmination of a unique, two-year-long collaboration between fiction writers and pioneering physicists.
As part of Comma’s Science-into-Fiction series, the project paired award-winning UK writers with leading physicists and engineers working at CERN, to explore different aspects of CERN’s research, as well as its historical legacies, through fiction and accompanying essays (or afterwords) by the scientists.
The project began in the Summer of 2021 when particle physicists connected to CERN around the world were invited to be part of a new European-wide public engagement project. Over 150 topic submissions from scientists working on different aspects of science were received. Writers were then invited to respond to the list of ideas and were paired with the physicists whose ideas inspired them. We were overwhelmed with positive responses.
Quantum computing has entered a bit of an awkward period. There have been clear demonstrations that we can successfully run quantum algorithms, but the qubit counts and error rates of existing hardware mean that we can’t solve any commercially useful problems at the moment. So, while many companies are interested in quantum computing and have developed software for existing hardware (and have paid for access to that hardware), the efforts have been focused on preparation. They want the expertise and capability needed to develop useful software once the computers are ready to run it.
For the moment, that leaves them waiting for hardware companies to produce sufficiently robust machines—machines that don’t currently have a clear delivery date. It could be years; it could be decades. Beyond learning how to develop quantum computing software, there’s nothing obvious to do with the hardware in the meantime.
But a company called QuEra may have found a way to do something that’s not as obvious. The technology it is developing could ultimately provide a route to quantum computing. But until then, it’s possible to solve a class of mathematical problems on the same hardware, and any improvements to that hardware will benefit both types of computation. And in a new paper, the company’s researchers have expanded the types of computations that can be run on their machine.
When neutron stars collide they produce an explosion that is, contrary to what was believed until recently, shaped like a perfect sphere. Although how this is possible is still a mystery, the discovery may provide a new key to fundamental physics and to measuring the age of the universe. The discovery was made by astrophysicists from the University of Copenhagen and has just been published in the journal Nature.
Kilonovae—the giant explosions that occur when two neutron stars orbit each other and finally collide—are responsible for creating both great and small things in the universe, from black holes to the atoms in the gold ring on your finger and the iodine in our bodies. They give rise to the most extreme physical conditions in the universe, and it is under these extreme conditions that the universe creates the heaviest elements of the periodic table, such as gold, platinum and uranium.
But there is still a great deal we do not know about this violent phenomenon. When a kilonova was detected at 140 million light-years away in 2017, it was the first time scientists could gather detailed data. Scientists around the world are still interpreting the data from this colossal explosion, including Albert Sneppen and Darach Watson from the University of Copenhagen, who made a surprising discovery.
Quantum dots are semiconductor particles measuring just a few nanometres across, which are now widely studied for their intriguing electrical and optical properties.
Through new research published in EPJ B (“Third-order nonlinear susceptibility in CdS/Cdx1Zn 1-x1 S/ZnS multilayer spherical quantum dot,”), Kobra Hasanirokh at Azarbaijan Shahid Madani University in Iran, together with Luay Hashem Abbud at Al-Mustaqbal University College, Iraq, show how quantum dots containing spherical defects can significantly enhance their nonlinear optical properties.
By fine-tuning these defects, researchers could tightly control the frequency and brightness of the light emitted by quantum dots.
A team led by Professor Andrea Morello has just demonstrated the operation of a new type of quantum bit, called ‘flip-flop’ qubit, which combines the exquisite quantum properties of single atoms, with easy controllability using electric signals, just as those used in ordinary computer chips.
“Sometimes new qubits, or new modes of operations, are discovered by lucky accident. But this one was completely by design,” says Prof. Morello. “Our group has had excellent qubits for a decade, but we wanted something that could be controlled electrically, for maximum ease of operation. So we had to invent something completely new.”
Prof. Morello’s group was the first in the world to demonstrate that using the spin of an electron as well as the nuclear spin of a single phosphorus atom in silicon could be used as ‘qubits’ – units of information that are used to make quantum computing calculations. He explains that while both qubits perform exceptionally well on their own, they require oscillating magnetic fields for their operation.
Stephen Hawking was one of the greatest scientific and analytical minds of our time, says NASA’s Michelle Thaller. She posits that Hawking might be one of the parents of an entirely new school of physics because he was working on some incredible stuff—concerning quantum entaglement— right before he died. He was even humble enough to go back to his old work about black holes and rethink his hypotheses based on new information. Not many great minds would do that, she says, relaying just one of the reasons Stephen Hawking will be so deeply missed. You can follow Michelle Thaller on Twitter at @mlthaller.
MICHELLE THALLER: Dr. Michelle Thaller is an astronomer who studies binary stars and the life cycles of stars. She is Assistant Director of Science Communication at NASA. She went to college at Harvard University, completed a post-doctoral research fellowship at the California Institute of Technology (Caltech) in Pasadena, Calif. then started working for the Jet Propulsion Laboratory’s (JPL) Spitzer Space Telescope. After a hugely successful mission, she moved on to NASA’s Goddard Space Flight Center (GSFC), in the Washington D.C. area. In her off-hours often puts on about 30lbs of Elizabethan garb and performs intricate Renaissance dances. For more information, visit NASA.
TRANSCRIPT: Michelle Thaller: Yes Jeremy, a lot of us were really sad with the passing of Stephen Hawking. He was definitely an inspiration. He was one of the most brilliant theoretical physicists in the world, and of course, he overcame this incredible disability, his life was very difficult and very dramatic and I for one am really going to miss having him around. And I certainly miss him as a scientist too. He made some incredible contributions. Now, Stephen Hawking was something that we call a theoretical physicist, and what that means is that people use the mathematics of physics to explore areas of the universe that we can’t get to very easily. For example, conditions right after the Big Bang, the beginning of the universe, what were things like when the universe was a fraction of a second old? That’s not something we can create very easily in a laboratory or any place we can go to, but we can use our mathematics to predict what that would have been like and then test our assumptions based on how the universe changed over time. And one of the places that is also very difficult to go to is, could we explore a black hole? And this is what Stephen Hawking was best known for. Now, black holes are massive objects they’re made from collapsed dead stars, and the nearest black hole to us is about 3,000 light years away. That one is not particularly large, it’s only a couple times the mass of the sun. The biggest black hole that’s in our galaxy is about four million times the mass of the sun and that actually sits right in the heart of the Milky Way Galaxy. And right now you and I are actually orbiting that giant black hole at half a million miles an hour. These are incredibly exotic objects. The reason we call them black holes is that the gravity is so intense it can suck in everything, including light. Not even light, going through space freely at the speed of light, can escape a black hole, so talk about dramatic exotic objects that are difficult to do experiments on. Stephen Hawking laid down some of our basic understanding of how a black hole works. And one of the things he actually did was he even predicted that black holes can die. You would think that a collapsed star that forms a bottomless pit of gravity would exist forever, but Stephen Hawking used the laws of quantum mechanics and something called thermodynamics, how heat behaves in the universe, to prove that maybe black holes can evaporate over time. And of course, that’s a hugely significant thing. One of the reasons I think it’s very unfortunate he died is we’re actually right on the cusp of being able to do actual experiments with black holes. And I know that sounds like a strange thing to say, but there are some particle accelerators, I mean specifically the Large Hadron Collider, which is in Europe, that are about to get to high enough energies they’re going to smash particles together so hard that so much energy is generated they might be able to make tiny little black holes. Read full transcript on: https://bigthink.com/videos/michelle-thaller-ask-a-nasa-astr…-the-world
Measurements of the magnetic moment of the electron have achieved unprecedented accuracy, showing great potential for the search for physics beyond the standard model.
Despite its remarkable successes, the standard model of particle physics clearly isn’t complete—dark matter, dark energy, and the matter–antimatter asymmetry of the Universe are some of its most flagrant deficiencies. Experimenters thus eagerly search for anomalies that could provide hints on a theory that could complete or replace the standard model. The electron is a key player in this quest: its magnetic moment is both the most precisely measured elementary-particle property and the most accurately verified standard model prediction to date. New measurements by Gerald Gabrielse’s group at Northwestern University in Illinois [1] have determined the value of the electron’s magnetic moment 2.2 times more accurately than the previous best estimate, which was obtained in 2008 [2].
That’s exactly what researchers in Germany set out to do, making use of “acoustic holograms” to form distinct 3D shapes out of particles suspended in water — all in “one shot,” said study lead author Kai Melde, a researcher from the Max Planck Institute, in a press release.
According to a study on the work, published last week in the journal Science Advances, the researchers were able to create a helix and a figure 8 out of silica gel beads, assembled biological cells into spherical clumps, and even provided a compelling concept for forming the shape of a dove in future experiments.
These acoustic holograms work by cleverly manipulating the pressure exerted by high frequency ultrasonic waves via the inexpensive use of a conventionally 3D-printed plate.
