Astrophysical detectives point to a cosmic supernova explosion or explosions to explain ancient extinction events here on Earth.
An asteroid the size of a car has flown past Earth closer than any seen before without hitting the planet — and NASA admits: “We didn’t see it coming.”
Known as asteroid 2020 QG, NASA said the space rock passed 1,830 miles (2,950 km) above the southern Indian Ocean on Sunday.
If it had actually been on an impact trajectory, it would likely have become a “fireball” as it broke up in the Earth’s atmosphere, the US space agency said.
Two mathematicians say they’ve untangled the first part of Paul Erdos’s famously thorny and unproven conjecture. In a new paper they’ve uploaded to arXiv and submitted to journals, mathematicians Thomas Bloom and Olof Sisask say they’ve jumped the first hurdle in the Erdos conjecture. If this is true, the next generation of researchers could start from that point with the first part finished and in hand.
➗ You love numbers. So do we. Let’s nerd out over numbers together.
Circa 2017
Imagine you took all sunlight that hits our planet at any given moment, and focussed it on one (unfortunate) piece of Earth the size of a thumbnail. Now times that blistering intensity by 100, and you’re beginning to understand the insanity of the world’s most powerful X-ray laser.
In a surprise result, scientists have focussed the full intensity of this laser onto a single molecule, and the aftermath has given rise to a phenomenon no one’s ever seen before — a molecular ‘black hole’, which consumes anything in its path.
“We certainly weren’t expecting this from previous measurements,” one of the team, Sebastien Boutet from the US Department of Energy’s SLAC National Accelerator Laboratory, told Mashable.
:ooo
Astronomers have seen what appears to the first light ever detected from a black hole merger.
When two black holes spiral around each other and ultimately collide, they send out ripples in space and time called gravitational waves. Because black holes do not give off light, these events are not expected to shine with any light waves, or electromagnetic radiation. Graduate Center, CUNY astrophysicists K. E. Saavik Ford and Barry McKernan have posited ways in which a black hole merger might explode with light. Now, for the first time, astronomers have seen evidence of one of these light-producing scenarios. Their findings are available in the current issues of Physical Review Letters.
A team consisting of scientists from The Graduate Center, CUNY; Caltech’s Zwicky Transient Facility (ZTF); Borough of Manhattan Community College (BMCC); and The American Museum of Natural History (AMNH) spotted what appears to be a flare of light from a pair of coalescing black holes. The event (called S190521g) was first identified by the National Science Foundation’s (NSF) Laser Interferometer Gravitational-wave Observatory (LIGO) and the European Virgo detector on May 21, 2019. As the black holes merged, jiggling space and time, they sent out gravitational waves. Shortly thereafter, scientists at ZTF — which is located at the Palomar Observatory near San Diego — reviewed their recordings of the same the event and spotted what may be a flare of light coming from the coalescing black holes.
“At the center of most galaxies lurks a supermassive black hole. It’s surrounded by a swarm of stars and dead stars, including black holes,” said study coauthor Ford, a professor with the Graduate Center, BMCC and AMNH. “These objects swarm like angry bees around the monstrous queen bee at the center. They can briefly find gravitational partners and pair up but usually lose their partners quickly to the mad dance. But in a supermassive black hole’s disk, the flowing gas converts the mosh pit of the swarm to a classical minuet, organizing the black holes so they can pair up,” she says.
Circa 2017
Circa 2017Positron emission tomography (PET) image synthesis plays an important role, which can be used to boost the training data for computer aided diagnosis systems. However, existing image synthesis methods have problems in synthesizing the low resolution PET images. To address these limitations, we propose multi-channel generative adversarial networks (M-GAN) based PET image synthesis method. Different to the existing methods which rely on using low-level features, the proposed M-GAN is capable to represent the features in a high-level of semantic based on the adversarial learning concept. In addition, M-GAN enables to take the input from the annotation (label) to synthesize the high uptake regions e.g., tumors and from the computed tomography (CT) images to constrain the appearance consistency and output the synthetic PET images directly.
Circa 2012
Back in 1871, James Clerk Maxwell predicted that light exerts a force on any surface it hits. This radiation pressure was experimentally discovered some 30 years later and has since emerged as a hugely important force that is now exploited in systems such as solar sails and laser cooling.
Today, John Zhang and buddies at the University of Southampton in the UK go one better. These guys predict that a far more powerful optical force can exist between a metal or dielectric plate and a metamaterial, a substance with optical properties that have been engineered to control light in specific ways.
Metamaterials can be designed so they allow tiny oscillations of electrons called plasmons to exist on their surfaces. The oscillations are tiny–measured in nanometres, that’s about the same as the wavelength of visible light.
Circa 2016
A super-hard metal has been made in the laboratory by melting together titanium and gold.
The alloy is the hardest known metallic substance compatible with living tissues, say US physicists.
The material is four times harder than pure titanium and has applications in making longer-lasting medical implants, they say.
Circa 2018
Measuring one million times less than the width of a human hair, graphene is harder than diamonds and 200 times stronger than steel. Small, strong, and flexible, it is the most conductive material on earth and has the potential to charge a cell phone in just five seconds or to upload a terabit of data in one. It can be used to filter salt from water, develop bullet-stopping body armor, and create biomicrorobots.
These incredible properties have captured the attention of scientists and industry specialists around the world, all seeking to harness graphene’s potential for applications in electronics, energy, composites and coatings, biomedicine, and other industries.
Derived from graphite, the same graphite used in pencils and many other common use products, graphene is, ironically, one of the most expensive materials on the planet. This is because the process of chemically peeling off, or exfoliating, a single layer of graphene from graphite ore is cost-prohibitive on an industrial scale.
Circa 2016
By using heat and temperature to modify the orientation of atoms, scientists have created a spongy, ultrastrong material that is lighter than a zip-close bag.