Tag: physics

EmDrive

A group at NASA’s Johnson Space Center has successfully tested an electromagnetic (EM) propulsion drive in a vacuum – a major breakthrough for a multi-year international effort comprising several competing research teams. Thrust measurements of the EM Drive defy classical physics’ expectations that such a closed (microwave) cavity should be unusable for space propulsion because of the law of conservation of momentum.

there’s a low, but nonzero probability that we’ll have a reactionless drive by eoy:

Spacecraft equipped with a reactionless drive could potentially make it to the moon in just a few hours, Mars in 2-3 months, and Pluto within 2 years. that’s about 4x faster.

Pilot Wave Theory

The experiment that Steinberg and his team conducted was analogous to the standard 2-slit experiment. They used photons rather than electrons, and instead of sending those photons through a pair of slits, they passed through a beam splitter, a device that directs a photon along one of 2 paths, depending on the photon’s polarization. The photons eventually reach a single-photon camera (equivalent to the screen in the traditional experiment) that records their final position. The question “Which of 2 slits did the particle pass through?” becomes “Which of 2 paths did the photon take?”

Relativistic hydrodynamics

Researchers document their discovery of electrons in graphene behaving like a fluid. To make this observation, the team improved methods to create ultra-clean graphene* and developed a new way to measure its thermal conductivity. When the strongly interacting particles in graphene were driven by an electric field, they behaved not like individual particles but like a fluid that could be described by hydrodynamics. “Physics we discovered by studying black holes and string theory, we’re seeing in graphene. This is the first model system of relativistic hydrodynamics in a metal.”

Cold Fusion

on reputation traps.

there’s a sociological explanation why few people are willing to look at the evidence. They put their reputations at risk by doing so. Cold fusion is tainted, and the taint is contagious – anyone seen to take it seriously risks contamination. So the subject is stuck in a place that is largely inaccessible to reason – a reputation trap, we might call it. People outside the trap won’t go near it, for fear of falling in. ‘If there is something scientists fear, it is to become like pariahs’. People inside the trap are already regarded as disreputable, an attitude that trumps any efforts that they might make to argue their way out, by reason and evidence.

2019-06-11: Google is getting into the game.

This work should produce data that will be of interest to people beyond the remaining cold-fusion believers, and similarly, the team’s work on heated metal powders and hydrogen required them to make advances in calorimetry that could also prove useful. And the hydrogen-saturated palladium electrode work led to new data about the effects of such high loading on the metal structure, and how to measure these reliably.

Symmetry affects performance

We have 20 papers published as a result of our work on the Jamaican Symmetry Project. We began in 1996 with 285 rural Jamaican boys and girls with an average age of 8. 1 reason we chose rural Jamaica is that it is economically disadvantaged, and since we paid all families we recruited for the study, we got an extraordinarily high participation rate. We measured their symmetry from head to toe, including everything from ear length to foot length to their teeth, we X-rayed their hands. We measured them again for symmetry in 2006.

In 2010, we measured their sprinting speeds and – bingo! – knees stood out. There it was, it was incredible, knee symmetry alone strongly predicted sprinting speed. Not ankles, not feet, nor any other part of the body. If your knees were symmetrical when you were 8 years old, then you ran faster when you were 22 years old. That was true for males and females, and for 90m and 180m sprints alike.

This was such a striking finding that we raised the money to study elite sprinters in Jamaica. They are the best in the world. The same variable we isolated in rural Jamaicans held true for elite athletes. Knee symmetry predicted the best of the best runners. We looked at Shelly-Ann Fraser-Pryce, the current top female sprinter in the world, and her knees are so symmetrical we can’t tell them apart.