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Archive for the ‘physics’ category: Page 187

Dec 12, 2020

An outside-the-box take on time

Posted by in categories: cosmology, education, physics

The history of the Universe thus far has certainly been eventful, marked by the primordial forging of the light elements, the birth of the first stars and their violent deaths, and the improbable origin of life on Earth. But will the excitement continue, or are we headed toward the ultimate mundanity of equilibrium in a so-called heat death? In The Janus Point, Julian Barbour takes on this and other fundamental questions, offering the reader a new perspective—illustrated with lucid examples and poetically constructed prose—on how the Universe started (or more precisely, how it did not start) and where it may be headed. This book is an engaging read, which both taught me something new about meat-and-potatoes physics and reminded me why asking fundamental questions can be so fun.

Barbour argues that there is no beginning of time. The Big Bang, he maintains, was just a very special configuration of the Universe’s fundamental building blocks, a shape he calls the Janus point. As we move away from this point, the shape changes, marking the passage of time. The “future,” he argues, lies in both directions, hence the reference to Janus, the two-faced Roman god of beginnings and transitions.

Barbour illustrates his main points with a deceptively simple model known as the three-body problem, wherein three masses are subject to mutual gravitational attraction. In this context, the Janus point occurs when all three masses momentarily occupy the same point, in what is called a total collision. The special shape at the Janus point, explains Barbour, is an equilateral triangle, which is his model’s version of the Big Bang. I found this imagery helpful when trying to understand the more abstract, and necessarily less technical, application of this concept to general relativity.

Dec 9, 2020

Researchers capture roaming molecular fragments in real time

Posted by in categories: chemistry, physics

The observation of a chemical reaction at the molecular level in real time is a central theme in experimental chemical physics. An international research team has captured roaming molecular fragments for the first time. The work, under the supervision of Heide Ibrahim, research associate at the Institut national de la recherche scientifique (INRS), was published in the journal Science.

The research group of the Énergie Matériaux Télécommunications Research Centre of INRS, with support of Professor François Légaré, has used the Advanced Laser Light Source (ALLS). They have succeeded in shooting the first molecular film of “roamers”—hydrogen fragments, in this case—that orbit around HCO fragments) during a chemical reaction by studying the photo-dissociation of formaldehyde, H2CO.

Dec 9, 2020

Hurling Satellites Into Space Seems Crazy—but Might Just Work

Posted by in categories: physics, satellites

😃 So the old ways still work!


A startup called SpinLaunch wants to do away with costly launch rockets. Let’s look at the physics.

Dec 8, 2020

U.S. physicists rally around ambitious plan to build fusion power plant

Posted by in categories: energy, physics

Plan calls for a subtle but crucial shift toward applied research in Department of Energy fusion program.

Dec 8, 2020

Breakthrough optical sensor mimics human eye, a key step toward better artificial intelligence

Posted by in categories: physics, robotics/AI

Researchers at Oregon State University are making key advances with a new type of optical sensor that more closely mimics the human eye’s ability to perceive changes in its visual field.

The sensor is a major breakthrough for fields such as image recognition, robotics and artificial intelligence. Findings by OSU College of Engineering researcher John Labram and graduate student Cinthya Trujillo Herrera were published today in Applied Physics Letters.

Previous attempts to build a human-eye type of device, called a retinomorphic sensor, have relied on software or complex hardware, said Labram, assistant professor of electrical engineering and computer science. But the new sensor’s operation is part of its fundamental design, using ultrathin layers of perovskite semiconductors—widely studied in recent years for their solar energy potential—that change from strong electrical insulators to strong conductors when placed in light.

Dec 7, 2020

Reaching for the Stars: The Case for Interstellar Travel

Posted by in categories: physics, robotics/AI, space travel, sustainability

For now, it looks like our best bet for going interstellar is to rely on robotic spacecraft that are optimized for speed.


For countless generations, the idea of traveling to an extrasolar planet has been the stuff of dreams. In the current era of renewed space exploration, interest in interstellar travel has understandably been rekindled. However, beyond the realm of science fiction, interstellar space travel remains a largely theoretical matter.

Continue reading “Reaching for the Stars: The Case for Interstellar Travel” »

Dec 5, 2020

Spacecraft that flew outside the solar system find ‘unique physics’

Posted by in categories: physics, space

The Voyager probes have detected an entirely new kind of electron burst outside the solar system.

It is the first time this “unique physics” have been detected by a spacecraft, and could allow for new breakthroughs in our understanding of the “interstellar medium”, or the space between the stars.

The two Voyager spacecraft were launched by NASA more than 40 years ago, with the aim of flying to the far reaches of our solar system. They have now gone even further than that, reaching interstellar space, and exploring the gaps between the stars, giving us the first glimpses of what it might be like in that mysterious zone.

Dec 5, 2020

Physicists Are Closer to Knowing the Size of a Proton … Sort of

Posted by in category: physics

A new and potentially improved measurement of a proton’s charge radius brings scientists closer to an answer. But the issue is still unresolved.

Dec 2, 2020

Physicists Observe Trippy ‘Vortex Rings’ in a Magnetic Material For The First Time

Posted by in categories: materials, physics

Wherever you have fluid, there you can also find vortex rings.

Now, scientists have found vortex rings somewhere fascinating — inside a tiny pillar made of a magnetic material, the gadolinium-cobalt intermetallic compound GdCo2.

If you’ve seen smoke rings, or bubble rings under water, you’ve seen vortex rings: doughnut-shaped vortices that form when fluid flows back on itself after being forced through a hole.

Dec 2, 2020

04.10.97 Develop Ultrasensitive Gyroscope Based on Superfluid Helium

Posted by in categories: physics, transportation

Circa 1997


Berkeley — An ultrasensitive, superfluid gyroscope developed by physicists at UC Berkeley has the potential to surpass today’s most sensitive devices for measuring absolute rotation or spin.

In a paper in this week’s issue of Nature, physics professor Richard Packard and his colleagues, graduate students Keith Schwab and Niels Bruckner, report a proof-of-principle demonstration of the new device.

Continue reading “04.10.97 Develop Ultrasensitive Gyroscope Based on Superfluid Helium” »