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Mysterious darkness surrounds the Pinwheel Galaxy
European Space Agency & NASA
IN BRIEF Graphene radio is a wireless wonder
Spiral galaxy’s dark halo puts theorists in a spin THE Pinwheel Galaxy is a darker place than we suspected. Other large spiral galaxies, such as the Milky Way, boast star-speckled outer shells. But the edges of the Pinwheel are mysteriously barren, putting a wrinkle in one of the most widely held theories of galaxy growth. We think galaxies get bigger by snacking on dwarf galaxies that fall into their gravitational grasp. This process rips the dwarf galaxies apart and, over billions of years, they leave behind a faint halo of orphaned stars that surrounds the larger galaxy. We have seen such haloes around the Milky Way and our closest large
neighbour Andromeda, and simulations suggest that they should be common across the universe. But the most detailed measurement yet of mass distribution in the Pinwheel Galaxy has revealed that its edges are strangely devoid of stars (Astrophysical Journal Letters, doi.org/rbg). This implies that the galaxy has somehow grown large without feeding on many dwarfs, says study author Pieter van Dokkum at Yale University. “There are only a few galaxies that have been studied down to this limit, so it’s hard to say how typical this is,” says Kathryn Johnston at Columbia University in New York. But theorists may be in trouble if galaxies without haloes turn out to be common. “If we find that the Pinwheel is not an exception, there is something fundamentally wrong,” says van Dokkum.
Pompeii-like ash kept dino remains fresh IT’S hot storage. Millions of years before volcanic ash entombed the Roman town of Pompeii, a group of dinosaurs succumbed to a similar fate. China’s famous feathered dinosaur fossils owe their exquisite preservation to volcanic eruptions between about 130 and 120 million years ago. The Jehol fossils have transformed our understanding of dinosaurs by showing that the 16 | NewScientist | 8 February 2014
relatives of Velociraptor and T. rex had a feather-like body covering, like birds. The Jehol deposits also preserved soft tissue from early mammals and flowering plants. Baoyu Jiang of Nanjing University, China, and colleagues think they know why the remains are so well preserved. They found carbon layers on the bones with a structure and composition that suggests they are charred soft
tissue – and the limbs of skeletons are flexed as if they had been trapped in volcanic ash (Nature Communications, DOI: 10.1038/ ncomms4151). The authors make a strong case, says David Eberth of the Royal Tyrrell Museum in Drumheller, Alberta – but he points out they only looked at 14 animal fossils. “Their sample size is just too small,” he says. Other factors were probably involved in preserving Jehol fossils elsewhere in the area.
THREE letters beamed across a lab bench may spark a wireless revolution. A transmission of “IBM” was received by the first working radio chip to be made from graphene – sheets of carbon, each just one atom thick. In 2011, IBM researchers made a radio microchip with graphene transistors, but placing necessary metal components on top of the transistors damaged them, and the chip could not receive a signal. With funding from the US Pentagon’s defence research arm, Shu-Jen Han’s team at IBM’s lab in Yorktown Heights, New York, found a way to put the metal parts on the chip first and then add the transistors. The device worked perfectly, they claim (Nature Communications, doi.org/q9k). The graphene-based circuit uses less power than normal chips, making it attractive for use in wearable radio devices wanted for the US military.
Life’s best bet may be Alpha Centauri THE star next door could be putting our sun to shame. An analysis of what makes planets suitable for life says that Alpha Centauri B, the star closest to our sun, could host a world even more homely than Earth. René Heller of McMaster University in Hamilton, Ontario, Canada, and his team explored an array of criteria for habitability. They say that the best locale would be a planet slightly bigger than Earth orbiting an orange star like Alpha Centauri B. The planet’s higher gravity would create mostly shallow seas and gentle slopes – ideal for biodiversity – while the long-lived orange star would let life-friendly conditions persist for up to 10 billion years (Astrobiology, doi.org/q94).
IN BRIEF Graphene radio is a wireless wonder
Spiral galaxy’s dark halo puts theorists in a spin THE Pinwheel Galaxy is a darker place than we suspected. Other large spiral galaxies, such as the Milky Way, boast star-speckled outer shells. But the edges of the Pinwheel are mysteriously barren, putting a wrinkle in one of the most widely held theories of galaxy growth. We think galaxies get bigger by snacking on dwarf galaxies that fall into their gravitational grasp. This process rips the dwarf galaxies apart and, over billions of years, they leave behind a faint halo of orphaned stars that surrounds the larger galaxy. We have seen such haloes around the Milky Way and our closest large
neighbour Andromeda, and simulations suggest that they should be common across the universe. But the most detailed measurement yet of mass distribution in the Pinwheel Galaxy has revealed that its edges are strangely devoid of stars (Astrophysical Journal Letters, doi.org/rbg). This implies that the galaxy has somehow grown large without feeding on many dwarfs, says study author Pieter van Dokkum at Yale University. “There are only a few galaxies that have been studied down to this limit, so it’s hard to say how typical this is,” says Kathryn Johnston at Columbia University in New York. But theorists may be in trouble if galaxies without haloes turn out to be common. “If we find that the Pinwheel is not an exception, there is something fundamentally wrong,” says van Dokkum.
Pompeii-like ash kept dino remains fresh IT’S hot storage. Millions of years before volcanic ash entombed the Roman town of Pompeii, a group of dinosaurs succumbed to a similar fate. China’s famous feathered dinosaur fossils owe their exquisite preservation to volcanic eruptions between about 130 and 120 million years ago. The Jehol fossils have transformed our understanding of dinosaurs by showing that the 16 | NewScientist | 8 February 2014
relatives of Velociraptor and T. rex had a feather-like body covering, like birds. The Jehol deposits also preserved soft tissue from early mammals and flowering plants. Baoyu Jiang of Nanjing University, China, and colleagues think they know why the remains are so well preserved. They found carbon layers on the bones with a structure and composition that suggests they are charred soft
tissue – and the limbs of skeletons are flexed as if they had been trapped in volcanic ash (Nature Communications, DOI: 10.1038/ ncomms4151). The authors make a strong case, says David Eberth of the Royal Tyrrell Museum in Drumheller, Alberta – but he points out they only looked at 14 animal fossils. “Their sample size is just too small,” he says. Other factors were probably involved in preserving Jehol fossils elsewhere in the area.
THREE letters beamed across a lab bench may spark a wireless revolution. A transmission of “IBM” was received by the first working radio chip to be made from graphene – sheets of carbon, each just one atom thick. In 2011, IBM researchers made a radio microchip with graphene transistors, but placing necessary metal components on top of the transistors damaged them, and the chip could not receive a signal. With funding from the US Pentagon’s defence research arm, Shu-Jen Han’s team at IBM’s lab in Yorktown Heights, New York, found a way to put the metal parts on the chip first and then add the transistors. The device worked perfectly, they claim (Nature Communications, doi.org/q9k). The graphene-based circuit uses less power than normal chips, making it attractive for use in wearable radio devices wanted for the US military.
Life’s best bet may be Alpha Centauri THE star next door could be putting our sun to shame. An analysis of what makes planets suitable for life says that Alpha Centauri B, the star closest to our sun, could host a world even more homely than Earth. René Heller of McMaster University in Hamilton, Ontario, Canada, and his team explored an array of criteria for habitability. They say that the best locale would be a planet slightly bigger than Earth orbiting an orange star like Alpha Centauri B. The planet’s higher gravity would create mostly shallow seas and gentle slopes – ideal for biodiversity – while the long-lived orange star would let life-friendly conditions persist for up to 10 billion years (Astrobiology, doi.org/q94).