Site J is the primary target for Philae to land on Comet 67P Churyumov-Gerasimenko. Image Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM
The Rosetta spacecraft was launched in 2004 with the mission of becoming the first probe to perform a soft land on the body of a comet. Rosetta finally caught up with Comet 67P Churyumov-Gerasimenko on August 6 and has been looking for a good place to land ever since. The list of potential landing sites was reduced to just five a couple of weeks ago.
Metamaterials can be designed to produce negative angles of refraction. If the water in the glass exhibits negative refraction, the image of the pen below the water line is flipped as if viewed in a mirror / University of Pennsylvania
Metamaterials are man-made composites that interact with light and sound (and waves in general) in unconventional ways, resulting in exotic behavior that’s not found in nature. Now, researchers describing a new concept called “digital metamaterials” promise a simplified way of producing metamaterials—which are already being used to develop invisibility cloaks and hyperlenses that aren’t subject to the limitations of conventional materials.
Have some wood and 16 spare bowling balls on hand? Why not make a huge pendulum wave?
Due to conservation of energy, a weight on a pendulum that is released will swing out and hit a point of equilibrium at about the same amplitude, and kinetic energy will cause the motion to continue on until it is eventually slowed by air resistance and friction from the pivot point. However, period of the pendulum can be shortened by adjusting the length of the rod holding up the weight. That is, the shorter the line, the faster it goes back and forth.
Carbon dioxide is typically known as a gas, though it exists as a solid when it reaches temperatures below −78.5 °C (−109.3 °F). This process is called deposition, and goes directly from gas to solid. When temperatures warm up, it sublimates and goes directly back into a gas.
Something very interesting happens when you insert a coin into a block of the dry ice; it produces a shrill screech when contact is first made and will begin to vibrate, almost like the coin is shivering.
The persistence of social media is certainly changing how things are done. In a matter of minutes, you can wish an old friend happy birthday on Facebook, find a recipe for dinner on Pinterest, watch a how-to project on YouTube, and get up to the minute updates on events from Twitter. But social media isn’t just changing how we act; it’s actually changing our brains as well.