In the late 1990s, cosmologists made a prediction about how much ordinary matter there should be in the universe. About 5%, they estimated, should be regular stuff with the rest a mixture of dark matter and dark energy. But when cosmologists counted up everything they could see or measure at the time, they came up short. By a lot.
The subject of the 2018 Nobel Prize in physics, chirped pulse amplification is a technique that increases the strength of laser pulses in many of today’s highest-powered research lasers. As next-generation laser facilities look to push beam power up to 10 petawatts, physicists expect a new era for studying plasmas, whose behavior is affected by features typically seen in black holes and the winds from pulsars.
Twin shock waves produced by the galaxy’s central black hole could have inflated the gargantuan Fermi Bubbles about 6 million years ago, a new study suggests.
Just as a literature buff might explore a novel for recurring themes, physicists and mathematicians search for repeating structures present throughout nature.
For example, a certain geometrical structure of knots, which scientists call a Hopfion, manifests itself in unexpected corners of the universe, ranging from particle physics, to biology, to cosmology. Like the Fibonacci spiral and the golden ratio, the Hopfion pattern unites different scientific fields, and deeper understanding of its structure and influence will help scientists to develop transformative technologies.
Continue reading “Novel insight reveals topological tangle in unexpected corner of the universe” »
Researchers at MIT and elsewhere have combined the power of a super collider with techniques of laser spectroscopy to precisely measure a short-lived radioactive molecule, radium monofluoride, for the first time.
Precision studies of radioactive molecules open up possibilities for scientists to search for new physics beyond the Standard Model, such as phenomena that violate certain fundamental symmetries in nature, and to look for signs of dark matter. The team’s experimental technique could also be used to perform laboratory studies of radioactive molecules produced in astrophysical processes.
“Our results pave the way to high-precision studies of short-lived radioactive molecules, which could offer a new and unique laboratory for research in fundamental physics and other fields,” says the study’s lead author, Ronald Fernando Garcia Ruiz, assistant professor of physics at MIT.
In theory, other dimensions aren’t big enough to form black holes and consume our universe or it would have happened already.
Recent media reports have claimed that a NASA experiment has detected evidence of a parallel universe, but astrophysicists disagree.
NASA’s WFIRST mission will explore the universe, seeking answers to some of its biggest mysteries. From understanding the nature of dark energy to studying planets outside our solar system, this mission will expand our view of the cosmos. Join experts Wednesday, May 20 at 11 a.m. ET for an exciting announcement about the WFIRST mission.
The collision of two intense light beams may produce detectable signatures of dark matter particles called axions.
Axions—hypothetical particles that are much lighter than electrons—could hold the key to important physics puzzles, from the matter–antimatter asymmetry to the nature of dark matter. So far, the strongest constraints on their properties, such as their mass and how they couple to photons, come from astrophysical measurements that look for axions produced by photons interacting with magnetic fields inside the Sun. Now, Konstantin Beyer at the University of Oxford, UK, and colleagues propose a lab-scale experiment based on colliding intense laser beams. The researchers say that, for an important range of axion masses, their approach would be as sensitive as astrophysical searches but much less dependent on hard-to-test models of astrophysical axion-generation processes.
The team’s scheme is a variation of the “light-shining-through-a-wall” (LSW) method of axion detection. In LSW, axions created by a laser beam propagating in a magnetic field would be detected after passing through a wall that shields the detector from the laser photons. The team’s new scheme uses two laser beams, whose collision may produce axions through a light–light scattering process. After passing through the wall, the axions would be converted into detectable photons by a magnetic field.
String theory provides a microscopic description of the entropy of certain theoretical black holes—an important step toward understanding black hole thermodynamics.
In the 1970’s, theorists determined that black holes have entropy [1], a remarkable finding that points at analogies between these spacetime singularities and systems of particles, such as classical gases. The crucial proof was provided by Stephen Hawking, who demonstrated, using a quantum-mechanical framework, that black holes radiate as if they were black bodies with a specific temperature [2]. The analogy was completed by extending all four laws of thermodynamics to black holes [3]. In thermodynamics, entropy is an important bridge between the macroscopic and the microscopic world: In a gas, for instance, entropy relates macroscopic heat transfer to the number of available microscopic states of the gas molecules. Providing a similar microscopic explanation of black hole entropy is an important test for theories that aim to unify gravity and quantum mechanics.
