4,020 articles mezi dny 1.12.2019 a 31.12.2019

Year in Aerospace: Looking back at Boeing’s troubles, looking ahead to commercial triumphs

2019 was a tough year for the aerospace industry — a year when a control system flaw caused the second catastrophic crash of a 737 MAX jet and sparked a worldwide grounding of Boeing's fastest-selling plane. Nine months after the Ethiopian Airlines crash, which killed 157 people, the 737 MAX is still grounded. Boeing's CEO and the head of its commercial airplanes unit have been replaced,...

Meet Steve, the winter sky phenomenon

Steve has been around for eons, but has been mis-identified as aurora until nowHands up if you’ve ever seen Steve. No, not the chap living down the road, but Steve the winter sky phenomenon. First spotted by auroral photographers in 2016, “Steve” is a purple band of light, sometimes accompanied by green lines, nicknamed “picket-fences”.Although Steve shares similarities with auroras –...

Blazar variability

Active galactic nuclei (AGN) are supermassive black holes at the centers of galaxies that are accreting material. These AGN emit jets of charged particles that move at speeds close to that of light, transporting huge amounts of energy away from the central black hole region and radiating across the electromagnetic spectrum. Blazars are extreme examples of AGN in which the collimated jets are...

eDNA expands species surveys to capture a more complete picture

Tiny bits of DNA collected from waters off the West Coast allowed scientists to identify more species of marine vertebrates than traditional surveys with trawl nets. They also reflect environmental shifts such as unusual ocean temperatures that affect the organisms present, new research shows.