Lifeboat Foundation

Gravity might feel strong if you drop a bowling ball on your feet, but is in fact the weakest force. Compare it to electromagnetism: the pull of all the Earth’s gravity can’t stop you from picking up a paperclip with a refrigerator magnet. That weakness makes gravity incredibly difficult to measure.

A team of scientists in China are reporting that they have now performed the most precise measurement of gravity’s strength yet by measuring G, the Newtonian or universal gravitational constant. G relates the gravitational attraction between two objects to their masses and the distance between them. The new measurement is important both for high-powered atomic clocks as well as the study of the universe, earth science, or any kind of science that relies on gravity in some way.

This week, newspapers reported that a man had fallen into an art installation consisting of an 8-foot-deep circular hole painted black. It’s kinda not his fault.

This article was originally published at The Conversation. The publication contributed the article to Space.com’s Expert Voices: Op-Ed & Insights.

Philosophers have debated the nature of “nothing” for thousands of years, but what has modern science got to say about it? In an interview with The Conversation, Martin Rees, Astronomer Royal and Emeritus Professor of Cosmology and Astrophysics at the University of Cambridge, explains that when physicists talk about nothing, they mean empty space (vacuum). This may sound straightforward, but experiments show that empty space isn’t really empty – there’s a mysterious energy latent in it which can tell us something about the fate of the universe.

Rees was interviewed for The Conversation’s Anthill podcast on Nothing. This Q&A is based on an edited transcript of that interview.

Weird patches of the sky where the cosmic microwave background radiation looks funny could be signs of long-dead universes, physicist Roger Penrose said.

Richard Feynman once asked a silly question. Two MIT students just answered it.

A new conjecture in physics challenges the leading “theory of everything.” (Via The Atlantic)

A trio of researchers with The University of Hong Kong, Academia Sinica Institute of Astronomy and Astrophysics in Taiwan and Northwestern University in the U.S., has come up with an alternative theory to explain how some stellar-mass black holes can grow bigger than others. In their paper published in The Astrophysical Journal Letters, Shu-Xu Yi, K.S. Cheng and Ronald Taam describe their theory and how it might work.

Since the initial detection of gravitational waves three years ago, five more detections have been observed—and five of the total have been traced back to emissions created by two stellar-mass black holes merging. The sixth was attributed to neutron stars merging. As part of their studies of such detections, space researchers have been surprised by the size of the stellar-mass black holes producing the gravity waves—they were bigger than other stellar-mass black holes. Their larger size has thus far been explained by the theory that they grew larger because they began their lives as stars that contained very small amounts of metal—stars with traces of metals would retain most of their mass because they produce weaker solar winds. In this new effort, the researchers suggest another possible way for stellar-mass black holes to grow larger than normal.

The new theory starts out by noting that some supermassive black holes at the hearts of galaxies are surrounded by a disk of gas and dust. In such galaxies, there are often stars lying just outside the disk—stars that could evolve to become stellar-mass black holes. The researchers suggest that it is possible that sometimes, pairs of these stars wind up in the disk as they evolve into black holes. Such stellar-mass black holes would pull in material from the disk, causing them to grow larger. The researchers note that if such a scenario were to play out, it is also possible that the two merging stars could wind up with a synchronized spin resulting in a stellar-mass black hole that produces more gravity waves than if the spins had not been synchronized, making them easier for researchers to spot.

With gentle pulses from gigantic lasers, scientists at Lawrence Livermore National Laboratory in California transformed hydrogen into droplets of shiny liquid metal.

Their research, reported on Thursday in the journal Science, could improve understanding of giant gas planets like Jupiter and Saturn whose interiors are believed to be awash with liquid metallic hydrogen.

The findings could also help settle some fractious debates over the physics of the lightest and most abundant element in the universe.

Continue reading “Settling Arguments About Hydrogen With 168 Giant Lasers” »

Researchers at the University of California San Diego have demonstrated the world’s first laser based on an unconventional wave physics phenomenon called bound states in the continuum. The technology could revolutionize the development of surface lasers, making them more compact and energy-efficient for communications and computing applications. The new BIC lasers could also be developed as high-power lasers for industrial and defense applications.

“Lasers are ubiquitous in the present day world, from simple everyday laser pointers to complex laser interferometers used to detect gravitational waves. Our current research will impact many areas of laser applications,” said Ashok Kodigala, an electrical engineering Ph.D. student at UC San Diego and first author of the study.

“Because they are unconventional, BIC lasers offer unique and unprecedented properties that haven’t yet been realized with existing laser technologies,” said Boubacar Kanté, electrical engineering professor at the UC San Diego Jacobs School of Engineering who led the research.

Continue reading “New laser based on unusual physics phenomenon could improve telecommunications, computing” »