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Howard Brody, emeritus professor of physics at the University of Pennsylvania, serves up an answer to this question. Tennis can be played on almost any surface that can be made smooth enough to provide a consistent bounce of the ball: from acrylic to clay to grass. The interaction of a tennis ball and the surface of a tennis court during the five milliseconds that the two are in contact determines the character of the game for each of the different surfaces....

A gold aerogel, so light it can sit on a feather, or float on the froth on top of a cappuccino, has been developed by researchers at ETH Zurich. The 20 carat gold ‘foam’ is a thousand times lighter than its solid counterpart, and the lightest gold nugget ever to be made. Raffaele Mezzenga and colleages made the highly porous gold mesh by directly crystallising gold nanoparticles onto a gel network of β-lactoglobulin protein fibrils which then underwent supercritical carbon dioxide drying to produce an aerogel....

Originally posted on the Nature news blog Posted on behalf of Declan Butler. The World Health Organization (WHO) announced plans on October 24 to produce millions of doses of two experimental Ebola vaccines by the end of 2015. Hundreds of thousands of doses should be available to help affected countries before the end of June, the WHO said at the conclusion of a meeting in Geneva. Vaccine makers, high-level government representatives, and regulatory and other bodies gathered to discuss the design and timing of planned clinical trials, as well as issues of supply and funding for mass vaccination programmes....

Federal researchers are slowly testing 192 lasers that they hope will set off the world’s first controlled nuclear fusion reaction. The lasers are housed at the National Ignition Facility (NIF), a $4 billion complex the size of three football fields that is part of the Lawrence Livermore National Laboratory in Livermore, Calif. The facility’s construction was completed this spring with tests directing more than a megajoule of energy at a target (a megajoule is the energy consumed by 10,000 100-watt light bulbs in a second)....

Two spacecraft, one public and one private, linked in orbit today when SpaceX’s Dragon was attached to the International Space Station. The historic moment represented the first time a commercial spacecraft has ever docked at the weightless laboratory. NASA astronaut Don Pettit, controlling the space station’s 58-foot (18-meter) robotic Canadarm2, berthed the unmanned Dragon capsule, built by commercial company SpaceX (Space Exploration Technologies Corp.), to the space station’s Harmony node at 12:02 p....

PHYSICS OF THE IMPOSSIBLE: A SCIENTIFIC EXPLORATION INTO THE WORLD OF PHASERS, FORCE FIELDS, TELEPORTATION, AND TIME TRAVEL by Michio Kaku. Doubleday, 2008 “If at first an idea does not sound absurd, then there is no hope for it.” Einstein’s words make an apt motif for Kaku’s premise: just because something is impossible today doesn’t mean it will be impossible in the future. Kaku—a well-known theoretical physicist at the City University of New York and an accomplished writer—reminds us of how fantastic the World Wide Web would have seemed in 1908....

The Army has developed a new material designed to keep walls from blowing apart and sending fragments flying at high speed during explosions. The X-FLEX Blast Protection System, a wallpaperlike adhesive-backed tape developed by the U.S. Army Corps of Engineers’ Engineer Research and Development Center (ERDC) and Evansville, Ind.–based Berry Plastics Corp.’s Engineered Protective Systems division, is applied to walls and designed to absorb the shock of a blast, protecting occupants from flying concrete and metal turned into projectiles....

MUMBAI, India—On a drizzly Monday afternoon here a few weeks ago, patients crowded around a door in a hallway in P. D. Hinduja Hospital—a private, nonprofit facility that caters to around 350,000 people per year. There is a loud, steady roar of voices, and patients and nurses have to shoulder past one another to get through the door, which leads to the office of lung specialist Zarir Udwadia. The walls are clean and white, and the air carries the tangy smell of disinfectant....

By Heidi Ledford of Nature magazineProtective caps known as telomeres that help to preserve the integrity of chromosomes can also predict lifespan in young zebra finches (Taeniopygia guttata), researchers have found.Telomeres are stretches of repetitive DNA sequence that are found at the ends of chromosomes, where they help to maintain cell viability by preventing the fraying of DNA and the fusion of one chromosome to another. The relationship between normal ageing and telomere decline has long been suspected–and even asserted by some companies that measure customers’ telomere length–but the link remains unproven in humans (see “Spit test offers guide to health”)....

Lightning flashes above Lake Maracaibo in Venezuela more than anywhere else on earth and does so for a stunning 297 days of the year. Second place goes to Kahuzi-Biéga National Park in the Democratic Republic of the Congo. A new study of satellite data spanning 16 years shows that cloud-to-ground lightning and intracloud lightning occur most frequently over complex terrain—notably the foothills of rugged mountain regions, especially if a big, warm lake lies nearby (insets below)....

The Trump administration released its 2018 budget request today (March 16), a proposal that calls for the cancellation of NASA’s astronauts-to-an-asteroid mission along with four Earth Science missions and NASA’s Office of Education. The White House’s first budget request for NASA offers $19.1 billion for the space agency in 2018, a 0.8-percent decrease from 2017 space-spending levels, according to the Office of Management and Budget. NASA is currently working under funding approved by a continuing resolution that expires April 28....

When COVID-19 began its inexorable march across the planet, doctors noticed that diabetes was among the conditions that make people particularly vulnerable to the new infection. Diabetic patients are three times as likely as nondiabetics to develop a severe case of COVID and they are two to three times as likely to die of it. Doctors noticed something else as well: patients who had no history of diabetes sometimes developed severe diabetic symptoms while battling COVID, and some remained diabetic after COVID resolved....

Dear EarthTalk: I’ve noticed a lot of beach erosion along the eastern U.S. coast. Beaches are virtually nonexistent in places. Is this a usual cycle that will self-correct, or are these beaches permanently gone from sea level rise or other environmental causes? – Jan Jesse, Morristown, TN Unfortunately for beach lovers and owners of high-priced beach-front homes, coastal erosion in any form is usually a one-way trip. Man-made techniques such as beach nourishment—whereby sand is dredged from off-shore sources and deposited along otherwise vanishing beaches—may slow the process, but nothing short of global cooling or some other major geomorphic change will stop it altogether....

Why do some people feel as though one of their body parts is not truly part of them and go to crazy lengths to get rid of it? Paul D. McGeoch, a visiting scholar at the Center for Brain and Cognition at the University of California, San Diego, answers: Certain people hold a deep desire to amputate a healthy limb. They are not psychotic, and they fully realize that what they want is abnormal....

Lower-than-average winds in the western United States in the first half of the year have cut into production and revenues at wind farms there, according to company data. Now, the industry is trying to figure out how it will deal with variable weather in the future. Wind energy is booming in the United States, with prices at an all-time low. The sector grew 8 percent in 2014, boosting domestic capacity to almost 66,000 megawatts and providing around 4....

Did you like this article? Editorial Review This article has been reviewed for accuracy, reliability and adherence to academic standards prior to publication. The Greek historian Herodotus provides an accurate description of the devotion of the ancient Egyptians to cats in Book II of his Histories, but this passage is often cited out of context. Chapters II.66-67 are frequently anthologized without the preceding passage discussing how the Egyptians valued all animals and regarded them as sacred....

Did you like this article? Editorial Review This article has been reviewed for accuracy, reliability and adherence to academic standards prior to publication. For the Greeks magic (mageia or goeteia) was a wide-ranging topic which involved spells and evil prayers (epoidai), curse tablets (katadesmoi), enhancing drugs and deadly poisons (pharmaka), amulets (periapta) and powerful love potions (philtra). The modern separation of magic, superstition, religion, science, and astrology was not so clear in the ancient world....

Did you like this article? Editorial Review This article has been reviewed for accuracy, reliability and adherence to academic standards prior to publication. Trade and commerce in the medieval world developed to such an extent that even relatively small communities had access to weekly markets and, perhaps a day’s travel away, larger but less frequent fairs, where the full range of consumer goods of the period was set out to tempt the shopper and small retailer....

Ötzi the Iceman’s hard-core leather outfit would have made animal rights activists shudder. The 5,300-year-old iceman mummy, whose remarkably preserved body was found frozen in the Tyrolean Alps in Austria, once sported an outfit made almost completely of animal skin, new genetic evidence suggests. And scientists even know which animals were used to make this Stone Age getup. “We have discovered that the iceman’s clothes were composed of an array of different animals,” said study co-author Niall O’Sullivan, a doctoral candidate in archaeology at the University College Dublin in Ireland and researcher at the Institute for Mummies and the Iceman, EURAC research in Bolzano, Italy....

This year is starting to look a lot like 2018 for America’s power sector. That’s good news for natural gas, less so for coal and power-sector carbon emissions. Coal generation has continued to plummet in 2019. Electricity generation from coal fell 8% in the first quarter of 2019 compared with the same time last year, according to figures from the U.S. Energy Information Administration. The black rock represented just 26% of U....