Wave motion in a bay or near a beach can cause significant sediment transport. Individual granular particles, like sand, can be lifted by the passage of a single wave, but, over time, complex patterns form as the granular bottom surface shifts due to the waves. This video shows time-lapse footage of the ripples that form and move in submerged sand during many hours of wave motion. A slight imperfection in the surface causes a network of sand ripples to grow and spread. Once formed, those ripples shift and reform depending on changes in the wave conditions. (Video credit: T. Parron et al.)
Game Changer - this photo shows the landing legs of the SpaceX Falcon 9 launch vehicle first stage. After extensive testing using their Grasshopper test vehicle, the upcoming flight will be the first real mission trial of SpaceX’ approach to launch vehicle reusability. The mission is the 3rd operational resupply flight of a Dragon spacecraft to the International Space Station (ISS), named CRS3 and scheduled to launch on March 16 at 04:41 eastern time from Space Launch Complex 40 (SLC40) at Cape Canaveral.
“SpaceX believes a fully and rapidly reusable rocket is the pivotal breakthrough needed to substantially reduce the cost of space access,” according to the firm’s website.
SpaceX hopes to vastly reduce their already low $54 million launch cost when a reusable version of the Falcon 9 becomes feasible.Although this Falcon 9 will be sprouting legs, a controlled soft landing in the Atlantic Ocean guided by SpaceX engineers is still planned for this trip.
“However, F9 will continue to land in the ocean until we prove precision control from hypersonic thru subsonic regimes,” Musk quickly added in a follow-up twitter message.
If successful, the world of space launch will never be the same. The leap in capability is as dramatic as moving from having to buy a new car each time you want to drive somewhere, and instead using the same car over and over (as we take for granted these days). The cost of launching payloads into space will tumble by orders of magnitude, demand will soar, space will become accessible … you get the picture. And even if this first attempt should fall short of expectations, SpaceX’ history has proven they will learn from setbacks and keep trying until they succeed. Nonetheless, here’s hoping to a flawless flight!
As FYFD wraps up coverage of #Sochi2014, let’s take a look at a winter sport not currently contested at the Olympics. This year’s Winter Games featured 12 new events. Speed skiing was not among them, though it was a demonstration sport in the 1992 Olympics. Like many of the sports in Sochi, speed skiing is gravity-driven, and friction and drag serve only to slow competitors. Speed skiing is about getting from the top of the course to the bottom, in a straight line, as fast as possible. Athletes reach velocities as high as 250 kph (155 mph), and aerodynamics are of the utmost concern. The skiers’ rubberized speed suits include airfoil-shaped fairings behind their calves that mold the airflow, and athletes wear giant aerodynamic helmets to smooth flow over their heads and shoulders. They spend their entire descent in an aerodynamic tuck, arms extended ahead of them like a cyclist in a time trial. It looks a pretty crazy ride. Would you like to see it added to the Olympics? (Video credit: R. Sill/University of Cambridge)
Which tire will roll down the ski jump fastest and jump the farthest? A Formula One tire? An enormous bulldozer tire? The smallest tire? This clip from Japanese television has made the rounds in years past, but the video source disappeared. We watched it again when it reappeared on Metafilter. Gotta love the lab coats, white gloves, and the surprising last jump.
So which of these six tires would you guess makes the biggest jump? And why?