When air flows around the wing of an airplane, it creates vortices of swirling air. When that wing accelerates suddenly, two vortices form and circle in opposite directions. Sometimes these circles link with one another to create knots. Knots occur in nature and physicists have theorized for the last hundred years that they could be created in liquid, too. Physicists have now figured out a way to create them and have 3-D footage of the results, which were published in Nature Physics on Sunday.
The researchers used a 3-D printer to make cross-sections of tiny airplane wings. Then they put the wings in a tank of water that was electrically charged to have lots of tiny bubbles. The bubbles show movement in the tank. When the wing was pulled through the water, it created knots in its wake which were recorded in 3-D with a high-speed laser scanner.
This morning’s launch of SpaceX’s third Dragon capsule has the twittersphere all a-flutter. Falcon 9’s blastoff from Cape Canaveral initially appeared to be a success. Read More
On Friday, February 15, astronomers will get an unusually good look at a near-Earth asteroid called 2012 DA14. It will be the first time a known object of this size will come this close to Earth—a mere 8 percent the distance between us and our moon.
The asteroid, which measures 150 feet across, was first spotted by astronomers when it zoomed by Earth this time last year. This asteroid’s fly-bys occur about once a year since its orbit around the sun is very similar to our own.
While the country song by this title refers to tractors in an agricultural context, the tractor beam is actually a theoretical physics concept. This beam is said to draw particles toward its source instead of pushing them away. Since the theoretical existence of such a sci-fi-style beam was first proposed a few years back, most physicists have come to accept the concept, and many have been trying to prove its existence ever since.
Now researchers in the Czech Republic have built the first working example of this technology. Not only did their real-life tractor beam attract polystyrene particles, but the researchers were surprised to find it could also sort them.
The crew of the International Space Station would like to wish you very happy holidays this year, and it comes in the form of this pretty timelapse video. On their wishlist? World peace. They’d like to see a little more cooperation on the beautiful blue marble they orbit.
The most recently observed stellar explosion in our neighborhood
was Kepler’s supernova, spotted 400 years ago.
Scientists using a telescope atop a Hawaiian volcano have detected a pair of extra-bright supernovae, or star explosions, one of which is the oldest, most-distant supernova ever detected.
That explosion occurred 12 billion years ago, making it a billion years older than the oldest supernova ever seen before. Because they are so bright—about 10 to 100 times brighter than most supernovae—these superluminous supernovae extend the limit on how far scientists can look back in time when they study the stars, whose light takes so long to reach us that what they are showing us is a picture of the universe in the past. With these results, published in Nature, scientists are peering closer than ever before to the time of the Big Bang, 13.7 billion years ago. Read More
The Curiosity rover has looked for methane on the Red Planet and has found none, disappointing hopes for finding life—Earth’s main source of methane—on Mars.
Researchers had good reasons to pin their hopes for Martian life on methane. On Earth, living things, such as methanogenic microbes, wetlands, and cattle, release vast quantities of the stuff. Researchers thought that any methane found on Mars might have come from a living thing, too. Plus, in Mars’ atmosphere, methane would dissipate quickly, so any that they did find was likely to be fresh and might even indicate that its Martian producer was still alive.
Two stone discs and a flywheel may sound like a Flintstonian vehicle, but in fact, it’s the recipe for a new, rather high-tech device that scientists are using to study earthquakes in the lab, described in a recent Science paper.
Do not put liquid nitrogen in a sealed container. Without an outlet, the liquid will turn into a gas, pressure will build up extremely quickly, and BOOM! The whole thing will explode. But as you can see in the above video, with a few safety precautions—and 1500 ping-pong balls—Roy Lowry of Plymouth University managed to turn this phenomenon into an unforgettable learning experience.
If you’re reading this with a laptop sitting on your legs, you might have noticed that computers tend to warm up as they work, turning electrical energy into thermal energy. In fact, two-thirds of all the energy we use is lost as waste heat. Maybe, instead of just using the heat from your computer to keep your lap toasty, we should be harnessing that heat by turning it back into electricity. But the thermoelectric materials that convert thermal to electrical energy aren’t very good at their job. While they have some applications, the expense and inefficiency of current thermoelectric materials make them impractical for implementing at a large, power-saving scale. Until now: a new thermoelectric material might finally let us recover the energy lost to waste heat—at a reasonable price.