Making thin films out of semiconducting materials is analogous to how ice grows on a windowpane: When the
The post Chemists cook up three atom-thick electronic sheets has been published on Technology Org.
Globular star clusters are isolated star cities, home to hundreds of thousands of stars. And like the fast pace of cities, there's plenty of action in these stellar metropolises. The stars are in constant motion, orbiting around the cluster's center. Past observations have shown that the heavyweight stars live in the crowded downtown, or core, and lightweight stars reside in the less populated suburbs.
Eukaryotes—fungi, plants, us—are complex. Our large cells are characterized by their different compartments, many of which are neatly enclosed within a boundary of membrane. These compartments contain complex molecular machines that perform equally complex metabolic tasks: they degrade proteins, they splice RNA molecules, they engulf foreign bodies.
Prokaryotes, on the other hand—one celled organisms like bacteria—are simple, with a notable lack of internal membrane enclosed structures (i.e., nuclei) in their one and only cell. It has been assumed that eukaryotes must have somehow evolved from prokaryotes, but it has not been at all clear how that may have happened.
A clue came in 1977, when another branch type of prokaryotic life was discovered: archaea. They are single-celled organisms that lack nuclei and other structures, just like bacteria. But from an evolutionary standpoint, they are about as distant from bacteria as they are from eukaryotes. As soon as archaea were recognized, people started speculating that eukaryotes may have originated within the archaeal branch of life rather than the bacterial branch, or that eukaryotes and archaea might share a common ancestor.
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Thermal imaging, microscopy and ultra-trace sensing could take a quantum leap with a technique developed by researchers at
The post ORNL reports method that takes quantum sensing to new level has been published on Technology Org.
“The privilege of a lifetime is being who you are.” –Joseph Campbell
When you think about dark matter, you probably think of a few things: how mass and gravity don’t appear to line up, how there isn’t enough normal matter to account for the motions we see on scales of galaxies and up, and how it’s necessary to form the structure we see on the largest scales, from the early times of the cosmic microwave background to the cosmic web spanning billions of light years we see today.
Image credit: Tony Hallas, via http://www.qsimaging.com/gallery.html.
But what you might not realize is that without dark matter — a substance that doesn’t interact in any (yet) measurable, non-gravitational way with anything else (or even itself) in the Universe — life as we know it would be unable to exist. The gravitation from dark matter is the only thing keeping supernova ejecta from escaping from our galaxy, and enabling heavy elements to participate in later generations of stars, planets, and biochemical reactions.
Image credit: Babak Tafreshi/Dreamview.net, via http://twanight.org/newTWAN/photos.asp?ID=3003071.
Sounds crazy, I know, but it’s true. Here’s the science behind why.
Now at Ceres, Dawn's camera recorded this closer view of the dwarf planet's northern hemisphere and one of its mysterious bright spots on May 4. A sunlit portrait of a small, dark world about 950 kilometers in diameter, the image is part of a planned sequence taken from the solar-powered spacecraft's 15-day long RC3 mapping orbit at a distance of 13,600 kilometers (8,400 miles). The animated sequence shows Ceres' rotation, its north pole at the top of the frame. Imaged by Hubble in 2004 and then by Dawn as it approached Ceres in 2015, the bright spot itself is revealed to be made up of smaller spots of reflective material that could be exposed ice glinting in the sunlight. On Saturday, Dawn's ion propulsion system was turned on to spiral the spacecraft into a closer 4,350-kilometer orbit by June 6. Of course another unexplored dwarf planet, Pluto, is expecting the arrival of a visitor from Earth, the New Horizons spacecraft, by mid-July.In 2013 James Hone, Wang Fong-Jen Professor of Mechanical Engineering at Columbia Engineering, and colleagues at Columbia demonstrated
The post Two-Dimensional Semiconductor Comes Clean has been published on Technology Org.
