Magnetic field at Earth's core measured
BERKELEY, Calif., Dec. 16 (UPI) -- The University of California says one of its researchers has made the first-ever measurement of the strength of the magnetic field inside Earth's core.
Bruce A. Buffett, professor of earth and planetary science at UC Berkeley, says the magnetic field strength is 25 Gauss, about 50 times stronger than the field at the planet's surface, a university release said Thursday.
"This is the first really good number we've had based on observations, not inference," Buffett said. "The result is not controversial, but it does rule out a very weak magnetic field and argues against a very strong field."
A magnetic field inside the outer core means there is a lot of convection and thus a lot of heat being produced, Buffet said.
There are many likely sources of that heat, he said, including the residual heat from 4 billion years ago when the planet was hot and molten, release of gravitational energy as heavy elements sink to the bottom of the liquid core, and radioactive decay of long-lived elements such as potassium, uranium and thorium.
"A measurement of the magnetic field tells us what the energy requirements are and what the sources of heat are," Buffett said.
The cooling Earth originally captured its magnetic field from the planetary disk in which the solar system formed, a field that would have disappeared within 10,000 years if not for the heat produced inside the planet that regenerates and maintains the field, he said.
Report: Humanity 'pushing' plant resources
GREENBELT, Md., Dec. 16 (UPI) -- Humanity is pushing Earth's plant resources harder as population continues to grow and countries develop modern economies, a NASA report says.
A NASA research group says an increasing amount of Earth's total annual land plant production is being consumed, mainly for food but also for paper, clothing, livestock feed, firewood, biofuels and other uses, ScienceDaily.com reported Thursday.
From 1995 to 2005, human consumption of land plants rose from 20 percent to 25 percent of the total plant production of each year, Marc Imhoff at NASA's Goddard Space Flight Center in Greenbelt, Md., said.
Both total global consumption and per capita consumption are on the increase, the report says.
"The question is, 'How hard are we pushing the land?'" Imhoff said. "People are wary about that percentage creeping up. Most people consider that a high number, although we're still doing research."
The research does not predict a "doomsday" scenario, he said, but does point to some future likelihoods if current population and consumption trends hold.
"What we're realizing is the biosphere doesn't care whether you have a lot of people consuming a little or a few people consuming a lot," he said. "It's the total rate that matters.
"If, in future scenarios, it's going to go up to something like 50 percent, we're looking at a very high demand for land management to maximize productivity at all levels on the landscape and at the expense of all other uses, for example, carbon sequestration, habitat or water storage," he said. "We would be heading toward a place where the planet would be very carefully managed, from end to end."
Digital archive a linguistic gold mine
CAMBRIDGE, Mass., Dec. 16 (UPI) -- Google's archives are a resource for investigating language changes, adoption of new technologies and the collective memory for major events, researchers say.
The search company's digital archive of books from around the world has allowed researchers to track the frequency with which various words appeared in nearly 5.2 million books published between 1800 and 2000, ScienceNews.org reported Thursday.
Harvard University researchers Jean-Baptiste Michel and Erez Lieberman-Aidenand along with researchers at Google, Encyclopedia Britannica and the American Heritage Dictionary call their mathematical analysis of texts over time "culturomics."
"The sheer scale of this research -- 500 billion words traced over two centuries -- takes the breath away," Harvard cultural historian Robert Darnton, who was not involved in the project, said. "The first results point the way toward a rigorous, quantitative, historical linguistics."
In analyzing new words, the researchers estimated about 8,500 words entered the English language each year between 1950 and 2000, driving a 70 percent growth in the number of English words from 597,000 to 1.022 million.
And the speed with which new inventions are embraced, based on their entry into the language, has accelerated, they say.
Technologies invented from 1840 to 1880 took an average 50 years to achieve widespread mention in books, vs. 27 years for devices invented from 1880 to 1920, the researchers found.
Famous deep-sea submersible to get upgrade
WOODS HOLE, Mass., Dec. 16 (UPI) -- Alvin, one of the world's best-known submersible research craft, is about to get an upgrade that will transform its capabilities, U.S. scientists say.
The 46-year-old vessel was used in the discovery of the hot volcanic vents on the ocean floor that transformed ideas about where and how life could exist, famously located an H-bomb lost at sea and made one of the first surveys of the Titanic, the BBC reported Thursday.
The undersea veteran was withdrawn from service this week to prepare it for a two-phase, $40 million upgrade that will allow it to stay submerged longer and go much deeper than its current 14,800-foot limit.
"Going to 4,500 meters (14,800 feet) means we can dive in about 68 percent of the ocean," said Susan Humphris of the Woods Hole Oceanographic Institution in Massachusetts, which operates the submersible.
"When we go to 6,500 meters (21,000 feet), we will have access to 98 percent of the ocean. That will make a huge difference; there is so much more to see down there," she said.
Alvin made its first dive in 1965 and since then has completed more than 4,500 dives, carrying some 1,400 scientists and researchers to the ocean depths.
