AmbiguousProps

Scientists at the world’s largest atom smasher have released a blueprint for a much bigger successor that could help solve remaining enigmas of physics.

The plans for the Future Circular Collider — a nearly 91-kilometer (56.5-mile) loop along the French-Swiss border and even below Lake Geneva — published late on Monday put the finishing details on a project roughly a decade in the making at CERN, the European Organization for Nuclear Research.

People often think about archaeology happening deep in jungles or inside ancient pyramids. However, a team of astronomers has shown that they can use stars and the remains they leave behind to conduct a special kind of archaeology in space.

Mining data from NASA's Chandra X-ray Observatory, the team of astronomers studied the relics that one star left behind after it exploded. This "supernova archaeology" uncovered important clues about a star that self-destructed—probably more than a million years ago.

Today, the system called GRO J1655-40 contains a black hole with nearly seven times the mass of the sun and a star with about half as much mass. However, this was not always the case.

Originally GRO J1655-40 had two shining stars. The more massive of the two stars, however, burned through all of its nuclear fuel and then exploded in what astronomers call a supernova. The debris from the destroyed star then rained onto the companion star in orbit around it, as shown in the artist's concept.

Originally GRO J1655-40 had two shining stars. The more massive of the two stars, however, burned through all of its nuclear fuel and then exploded in what astronomers call a supernova. The debris from the destroyed star then rained onto the companion star in orbit around it, as shown in the artist's concept. With its outer layers expelled, including some striking its neighbor, the rest of the exploded star collapsed onto itself and formed the black hole that exists today. The separation between the black hole and its companion would have shrunk over time because of energy being lost from the system, mainly through the production of gravitational waves.

When the separation became small enough, the black hole, with its strong gravitational pull, began pulling matter from its companion, wrenching back some of the material its exploded parent star originally deposited. While most of this material sank into the black hole, a small amount of it fell into a disk that orbits around the black hole. Through the effects of powerful magnetic fields and friction in the disk, material is being sent out into interstellar space in the form of powerful winds.

This is where the X-ray archaeological hunt enters the story. Astronomers used Chandra to observe the GRO J1655-40 system in 2005 when it was particularly bright in X-rays. Chandra detected signatures of individual elements found in the black hole's winds by getting detailed spectra—giving X-ray brightness at different wavelengths—embedded in the X-ray light. Some of these elements are highlighted in the spectrum shown in the inset. The team of astronomers digging through the Chandra data were able to reconstruct key physical characteristics of the star that exploded from the clues imprinted in the X-ray light by comparing the spectra with computer models of stars that explode as supernovae.

They discovered that, based on the amounts of 18 different elements in the wind, the long-gone star destroyed in the supernova was about 25 times the mass of the sun, and was much richer in elements heavier than helium in comparison with the sun.

A paper describing these results titled "Supernova Archaeology with X-Ray Binary Winds: The Case of GRO J1655−40" was published in The Astrophysical Journal.

This analysis paves the way for more supernova archaeology studies using other outbursts of double star systems.

• Lucid plans to start delivering the Gravity SUV to regular customers next month, the company said on Friday.
• Since the start of production in December, it's been making Gravity SUVs for internal use and for a limited number of customers close to the company.
• The Gravity is the EV startup's second model and is key to its future.

Archive link: https://archive.is/6OfsL

Google fired 28 employees in connection with sit-in protests at two of its offices this week, according to an internal memo obtained by The Verge. The firings come after 9 employees were suspended and then arrested in New York and California on Tuesday.

In a memo sent to all employees on Wednesday, Chris Rackow, Google’s head of global security, said that “behavior like this has no place in our workplace and we will not tolerate it.”

He also warned that the company would take more action if needed: “The overwhelming majority of our employees do the right thing. If you’re one of the few who are tempted to think we’re going to overlook conduct that violates our policies, think again. The company takes this extremely seriously, and we will continue to apply our longstanding policies to take action against disruptive behavior — up to and including termination.”