Air and Space: The shocking resurrection of the F-15

Air and Space: The shocking resurrection of the F-15

By Preston Lerner

    The original F-15 was built to be a multi-capability fighter that could famously fight its way both in and out of trouble. It began as a one seater developed for air-superiority after Russian aircraft began defeating the U.S. in dogfights during the Vietnam War. It later evolved into the F-15E, the two seater, two engine fighter, variations of which are sold to other countries long after the last Air Force purchase in 2004.

    Soon, it will be produced as the F-15EX with one of the best flight and mission control systems in the world. There has been much debate over the Air Force decision to procure these planes. Many people believe that the AF needs newer, fifth-generation air craft, which can avoid detection by radars. However, the F-15 won out, primarily due to its cost. It is much cheaper than F-35, a fifth-generation plane. On top of that, anti-radar planes also need a special coating, upping upkeep costs. Of course, it has an amazing flight record as well, topping out at Mach 2.5, carrying 18 and 12 of air-to-ground and air-to-air missiles, all with 100% mission completion. the Air Force has asked for money to buy 8 of the updated version in its latest budget request.

National Geographic: How devastating pandemics change us

National Geographic: How devastating pandemics change us

By Richard Conniff

    We have had many pandemics to teach us lessons on how to avoid them in the past. But every time, we forget when it is just out of sight.

    Vaccines were discovered in the 1700s to fight smallpox. The first vaccine was created from the pustules on infected people, then later perfect to cowpox viruses, which milk maids had found to protect against smallpox later on. It took a while for the idea to catch on, but eventually led to the eradication of smallpox.

    People once believed that bad smells and the four humors caused disease. But as people moved to the larger cities with every decreasing sanitary conditions, scientists began to learn that dirty streets and people transmitted infections, leading to cleaner cities.

    More recently, Louis Pasteur and Robert Koch, although bitter enemies, made huge breakthroughs by proving that tiny microbes cause disease, and that heat can be used to kill them. They also found that these bacteria can reproduce like normal organisms to spread. Koch, although largely unrecognized, showed that the bacteria form spores in the case where they cannot find new hosts, thereby preserving themselves until they can spread again.

    We have entered the frightening pandemic world of our ancestors. And the big takeaway is this. When this is all past, we cannot just forget. We must remember, learn. Because the next great pandemic is lurking out there somewhere.

TedEd: How rollercoasters affect your body

A TedEd by Brian D. Avery

Rollercoasters used to be much more dangerous. In 1895, crowds watched on the Coney Island boardwalk as the Flip Flap Railway took passengers for the first time. It was the first ever looping rollercoaster, but its thrills came at a price. People suffered neck injury and whiplash, and in severe cases, were ejected. Today, we can have far more thrilling rides without such dangers. How? Rollercoasters are operated using gravitational force, building potential energy as they go up, and releasing kinetic energy as they go down. But early designers were so concerned with making sure the cars didn't get stuck halfway up that they overcompensated. They failed to account for the fact that gravity affects your body as well. G-forces are the units used by most people to describe the amount of gravitational force, with 1G being normal gravity. Today, we know that bodies can handle around 5G's, whereas old rollercoasters were up around 12G's. At that amount, blood rushes to different parts of the body, causing blackouts, dizziness, and crimson vision. At negative G's riders become weightless, potentially making them fly out without the proper precautions. Modern straps and buckles have largely solved this problem, and there are also no sharp turns, which prevent whiplash and back pain. Increased G-forces also multiply weight, and sturdier rails have also allowed for better rides.