Category Environment/Geology

A rock fulgurite revealed that lightning strikes alter quartz’s crystal structure on the atomic level.

Researchers once believed only meteorites could do so. At a rock outcropping in southern France, a jagged fracture runs along the granite. The surface in and around the crevice is discolored black, as if wet or covered in algae. But the real explanation for the rock’s unusual features is more dramatic: a powerful bolt of lightning.

Using extremely high-resolution microscopy, Prof Gieré et al found that not only had the lightning melted the rock’s surface, resulting in a distinctive black “glaze,” but had transferred enough pressure to deform a thin layer of quartz crystals beneath the surface, resulting in distinct atomic-level structures called shock lamellae...

Walking on water might sound supernatural, but in fact it is a quite natural phenomenon. Many small creatures use water’s surface tension to maneuver around. One of the most complex maneuvers, jumping on water, is achieved by a species of semi-aquatic insects called water striders that not only skim along water’s surface but also generate enough upward thrust with their legs to launch themselves airborne from it.

Now, emulating this natural form of water-based locomotion, an international team of scientists from Seoul National University (SNU), Harvard’s Wyss Institute for Biologically Inspired Engineering, and Harvard John A. Paulson School of Engineering and Applied Sciences, has unveiled a novel robotic insect that can jump off of water’s surface...

Hierarchical structure of wood fibers and the characteristic of cellulose fibrils. Note the rich interchain hydrogen bonds among neighboring cellulose molecular chains.

Paper made of cellulose fibers is tougher and stronger the smaller the fibers get. For a long time, engineers have sought a material that is both strong (resistant to non-recoverable deformation) and tough (tolerant of damage). “Strength and toughness are often exclusive to each other,” said Teng Li, associate professor of mechanical engineering at UMD. “For example, a stronger material tends to be brittle, like cast iron or diamond.”

The UMD team pursued the development of a strong and tough material by exploring the mechanical properties of cellulose, the most abundant renewable bio-resource on Earth...

A new NASA study of ocean temperature measurements shows in recent years extra heat from greenhouse gases has been trapped in the waters of the Pacific and Indian oceans. Researchers say this shifting pattern of ocean heat accounts for the slowdown in the global surface temperature trend observed during the past decade. Jet Propulsion Laboratory (JPL), CA, found a specific layer of the Indian and Pacific oceans between 300 and 1,000 ft below the surface has been accumulating more heat than previously recognized. They also found warm water movt has affected surface temps.

“Greenhouse gases continued to trap extra heat (in the 20th century), but for about 10 years starting in the early 2000s, global average surface temperature stopped climbing, and even cooled a bit,” said Willis...