Scientists in West Australia struck gold when they found high concentrations of the precious metal in termite hills. These gold-laden sediments are a good indication of deposits underground.
Enlisting the earth-moving skills of the termite takes some of the guesswork out of modern gold prospecting. Gold has been mined in this area of Australia for a century and a half, but as eroded sediments collect on the surface, the gold deposits get buried and become harder to find. When termites deliver the soil samples, researchers don’t have to drill in hopes of finding them, which makes the scouting process cheaper and less invasive.
Golden and gleaming, this convex mirror arrived last week at the Goddard Space Flight Center in Greenbelt, Md., where it will be mounted on the much-anticipated Webb telescope. When the telescope is up and running, sometime later this decade, the Webb will take the title of the most powerful space telescope ever built, ousting even the Hubble. The Boulder-built mirror’s color comes from a microscopic layer of gold, 1,000 times thinner than a human hair. The gold will help the telescope better reflect infrared light, making distant planets and the universe’s first galaxies easier to see.
Image Credit: Chris Gunn, NASA
The Crusades were a time of religious conflict, when territory and castles were won with bloody battles and then quickly lost again—and with all that brouhaha, who had time to make new coins? When the Christian Knights Hospitaller buried a jug of 108 gold coins at the castle of Apollonia, a now-deserted stronghold north of modern-day Tel Aviv, they were probably hoping to preserve their hoard from the Egyptian soldiers then besieging the fortress. Although they never returned for their money, its recent discovery is telling researchers a lot about Crusader economics and raising new questions—like why the Christians used primarily gold dinars forged by the Fatimids hundreds of years earlier, rather than minting their own currency, something that would have demonstrated their wealth, power, and cultural identity. Many of the coins found in the crusader castle, oddly enough, are emblazoned with the names of Muslim sultans.
Image courtesy of the American Friends of Tel Aviv University
The universe is more massive than it looks. Although it’s invisible to the eye, this extra mass, called dark matter, seems to interact with visible matter through gravity and the weak nuclear force. Some researchers hypothesize that dark matter consists of WIMPs, or weakly interacting massive particles, which form an invisible “sea” through which the Earth passes as our planet travels through space. While these WIMPs would ordinarily fly right through ordinary matter, we might be able to observe the rare occasions when one directly strikes a nucleus.
One big challenge to WIMP detection is proving that a collision was due to a WIMP, and not to another type of fly-by particle. Some projects are dealing with this problem by burying their detectors deep underground where no interfering radiation can reach; some are using the fact that the number of WIMP collisions is expected to change throughout each day and each year, as Earth’s position in the sea of WIMPS changes. (This approach is similar to the Michaelson-Morley experiment, which disproved the existence of luminiferous aether, another invisible “sea” we supposedly orbited through.) Now an interdisciplinary group of physicists and biologists has an idea to take the comparison of daily and annual measurements to the next level.
The gold ring around your finger may symbolize “till death do us part” for you, but for scientists, it poses a problem.
That shiny band probably cost a small fortune at the jewelry store, but gold is actually abundant on the Earth’s surface (which helps explain why it’s the ideal form of money). The difficulty is, when scientists apply what they know about how the solar system formed, it’s hard to explain how all that gold (and other precious metals that bond easily to iron, like palladium and platinum) got into the Earth’s crust, where bling-loving humans could get at it. A new study in Science sets forth an explanation: In the Earth’s younger days, impacts by huge objects—perhaps even one as big as Pluto—may have brought it here.
To explain this theory, let’s start with the most dramatic impact in our planet’s history: the one that formed the moon and re-melted the solidifying Earth in the process.
Moon rocks brought back during the Apollo missions led to the now widely accepted theory that the moon formed when a Mars-size object crashed into early Earth. Energy from the impact would have spurred the still forming Earth to develop its mostly iron core. When this happened, iron-loving metals should have followed molten iron down from the planet’s mantle and into the core. But we know that gold and other iron-lovers are found in modest abundances in Earth’s mantle. [National Geographic]