Sep 27, 2019
Hidden Gravitational Wave Signal Reveals that Black Holes Are ‘Bald’
Posted by Saúl Morales Rodriguéz in categories: cosmology, physics
Are black holes bald or hairy? It all depends on the details of a fleeting gravitational wave.
Are black holes bald or hairy? It all depends on the details of a fleeting gravitational wave.
In two breakthroughs in the realm of photonics, City College of New York graduate researchers are reporting the successful demonstration of an LED (light-emitting diode) based on half-light half-matter quasiparticles in atomically thin materials. This is also the first successful test of an electrically driven light emitter using atomically thin semiconductors embedded in a light trapping structure (optical cavity).
The research is led by graduate physics student Jie Gu and post-doctoral fellow Biswanath Chakraborty, in collaboration with another graduate student, Mandeep Khatoniyar.
According to Vinod Menon, chair of physics in City College’s Division of Science and the research team’s mentor, their double feat, reported in the journal Nature Nanotechnology, marks an important milestone in the field of 2-D materials and, more broadly, LEDs.
More than 9000 scientists, including Andre Geim, Carlo Rubbia and eight other Nobel-prize-winning physicists, have signed a letter calling on the European Commission (EC) to reinstate a dedicated commissioner for education and research. The letter claims that that an out-and-out role for education and research is necessary to create a sound basis for innovation in Europe.
News of the apparent sidelining of science emerged when Ursula von der Leyen, the EC’s president-elect, presented her team and the new structure of the next European Commission on 10 September. It included her candidates for the new set of 18 commissioners, but the plan no longer included a commissioner that explicitly represents education and research.
These areas are instead expected to be covered by the commissioner for innovation and youth – the nominee for which is Mariya Gabriel, who is the current commissioner for digital economy and society. In the new set-up, the innovation and youth role appears to be a merger between the current directorate for research, science and innovation with that for education, culture, youth and sport.
DARK MATTER has long eluded our understanding but scientists searching for evidence of new physics capable of explaining such enduring mysteries of the Universe may have moved one step closer, following the latest CERN research.
It’s hard living in a relativistic Universe, where even the nearest stars are so far away and the speed of light is absolute. It is little wonder then why science fiction franchises routinely employ FTL (Faster-than-Light) as a plot device.
Push a button, press a petal, and that fancy drive system – whose workings no one can explain – will send us to another location in space-time.
However, in recent years, the scientific community has become understandably excited and skeptical about claims that a particular concept – the Alcubierre Warp Drive – might actually be feasible.
CAS has announced the research program “Taiji” that will study gravitational waves from the merging of binary black holes and other celestial bodies.
Unlike the LIGO research conducted from a ground-based observatory, Taiji will conduct space-based detection on the gravitational waves with lower frequencies to observe celestial bodies with greater mass or located farther away in the universe, said Wu Yueliang, chief scientist of the Taiji program and an academician of CAS.
However, the gravitational wave signals from those celestial bodies are extremely weak, posing great challenges for detection. Scientists need to break through the limit of current precise measurement and control technology, Wu said.
Circa 2016
We humans are pretty into the idea of finding aliens, but have we really thought through what would happen if we stumbled across extraterrestrial intelligence that didn’t want to ‘come in peace’, and instead was hell-bent on mining our fair planet for everything it’s got?
No? Well, luckily for us reckless daydreamers, astronomers have our back, and have come up with a pretty solid plan that would cloak our planet from any bad-guy aliens out there looking for us. And it relies entirely on lasers (what else?).
People have known about magnets since ancient times, but the physics of ferromagnetism remains a mystery. Now a familiar puzzle is getting physicists closer to the answer.
Supernova explosions can crush ordinary stars into neutron stars, composed of exotic, extremely dense matter. Neutron stars are on the order of about 12 miles (20 km) across in contrast to hundreds of thousands of miles across for stars like our sun. Yet they contain mass on the order of 1.4 times that of our sun. Neutron stars have strong magnetic fields. They emit powerful blasts of radiation along their magnetic field lines. If, as a neutron star spins, its beams of radiation periodically point towards Earth, we see the star as a pulsing radio or gamma-ray source. Then the neutron star is also called a pulsar, often compared to a cosmic lighthouse. Modern astronomers know of pulsars spinning with mind-boggling rapidity. The second-fastest one – called PSR J0952-0607 – spins some 707 times a second! Scientists at the Max Planck Institute for Gravitational Physics in Hanover, Germany announced on September 19, 2019, that this pulsar, J0952-0607 – formerly seen only at the radio end of the spectrum – now has been found to pulse also in gamma rays.
J0952-0607 – the number relates to the object’s position in the sky – was first discovered in 2017. It was originally seen to pulse in radio waves, but not gamma rays. The international team that studied it in detail – and recently published new work about it in the peer-reviewed Astrophysical Journal – said in a statement:
The pulsar rotates 707 times in a single second and is therefore the fastest spinning in our galaxy outside the dense stellar environments of globular clusters.