FactorTechnology

The People's Liberation Army Air Force has officially deployed its J-20 stealth fighters to frontline fighter squadrons. Shen Jinke, a PLAAF spokesman, told the Xinhua News Agency that the new fighters were ready to "safeguard China's sovereignty, security and territorial integrity." The PLA's English website also mentions the J-20's newfound operational status, which suggests the announcement was meant to raise the international profile of the modernizing Chinese military. The J-20 is a "fifth-generation" heavy, twin-engine stealth fighter with canards (appendages on the wings that offer greater stability), advanced active electronically scanned array (AESA) radar, and three internal weapons bays for air-to-air missiles and bombs. Similarly to to Lockheed Martin's F-22 Raptor and Russia's Su-57 fighters, the J-20 is a high-speed fighter that's very maneuverable, with capacity for long range and stealth. READ MORE AT: https...

Sleep is a time suck. If you multiplied the average recommended number of hours we should sleep in a day—eight for a typical adult—by the number of days in an average lifespan (78.8 years in the United States), that would amount to about 9,587.3 days. That’s one third of your life spent unconscious. From an evolutionary standpoint, sleep is quite literally a waste of your time, yet it’s fought its way through countless years of adaptation in nearly every living animal on Earth. So it must be important, right? READ MORE AT: https://www.popsci.com/how-many-hours-sleep-do-you-actually-need

Every time you send an email or text, or even look up a friend's address on Google Maps, you rely on a digital list of your contacts. But just because you use it all the time doesn't mean you treat it very well. Many of us let old numbers, needless duplicates, and unlabeled mystery addresses pile up in whatever contacts app we prefer. This makes it harder to find the information we need when we need it. Luckily, the apps that store contact lists—we're focusing on those from Google, Apple, and Microsoft—can help you clean up duplicates, delete contacts with missing or outdated information, and sync these changes between apps and devices. In general, to avoid having your contacts list sprawl across too many accounts, we'd recommend that you pick one of these contacts services to serve as your primary account, based on the apps and devices you rely on the most (heavy iPhone users should go through Apple, Android devotees should pick Google, and so on). Once you...

Do you trust that your drinking water is safe? Recent surveys suggest that nearly half of Americans are unsure. In the wake of environmental tragedies like the Flint water crisis, it's not shocking that many citizens feel this way. But while the technology exists to take testing into ones own hands, monitoring air and water quality is still generally considered the responsibility of a municipality, not an individual homeowner. That is, of course, as it should be. Still—if official promises of safety can't always be trusted, can at-home products make up for government shortcomings? READ MORE AT: https://www.popsci.com/at-home-testing-contaminants

Why a strand of hair bends or falls the way it does may sound like a simple question, but the answer is rather convoluted. On one level, the texture of a person's hair derives from his or her genes. A 2009 study looked at the genetics of waves and curls and reported a heritability of between 85 and 95 percent. (That means about nine tenths of the variation in hair texture within the sample could be ascribed to DNA.) How does this play out at the level of a single hair? Research shows that the curvature of a strand depends on the nature of its follicle. When a follicle is asymmetrical, the hair that it produces is oval in shape and tends to curl. When it's symmetrical, the strand that emerges grows round and straight. READ MORE AT: https://www.popsci.com/science/article/2012-11/fyi-what-maks-hair-curly