Messenger’s data provides details on Mercury’s past
Mercury’s magnetic field is nearly 4 billion years old, researchers have found.
A planet’s magnetic field is generated by the flow of liquid iron deep in its core. While Earth’s magnetic field helps shield life here from solar radiation, Mercury is unlikely to be harboring inhabitants that need protection.
Still, the information is useful because it “is dating processes in the interior of the planet, and it basically tells us something about Mercury’s past,” said Catherine Johnson, a geophysicist at the University of British Columbia and an author of the new study, published in the journal Science.
Mercury, like all of the planets in our solar system, is just over 4.5 billion years old.
The data were gathered by NASA’s Messenger, a small spacecraft that orbited Mercury for four years before crashing into the planet on April 30. The spacecraft measured the magnetism of rocks on Mercury’s surface. Johnson and her colleagues will continue to analyze data from Messenger.
Ancient arthropod offers clues on evolution of heads
A 500-million-year-old fossilized arthropod found in the Burgess Shale, a fossil field in the Canadian Rockies, may provide clues to how heads evolved in early animals. The fossil is a submarine-shaped arthropod, Odaraia alata, of the Middle Cambrian Period. A paper in Current Biology reports that both Odaraia alata, originally found about 100 years ago, and another ancient arthropod have a hard plate, known as the anterior sclerite, and eye-like features that were connected by nerves to their brains. They may have controlled their vision in much the same way that modern insects, crustaceans and spiders do.
Chilean child finds pieces of T-rex cousin
A 7-year-old boy in Chile has discovered bone fragments of a previously unknown dinosaur. Named Chilesaurus diegosuarezi – after the country and the boy, Diego Suarez – the new dinosaur is closely related to Tyrannosaurus rex but was a herbivore. Chilesaurus was about the size of a turkey, had unusually short arms, a long neck, a small head and leaf-shaped teeth. Diego found the bones while accompanying his parents, geologists Manuel Suarez and Rita de la Cruz, as they studied rocks in Chilean Patagonia.
– New York Times