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Space telescope spots ‘invisible’ galaxies
IN BRIEF
For new stories every day, visit www.NewScientist.com/news
Add ice for more Mysterious matter flow suggests inflation was incomplete precise transistors IS THERE a bulk flow of matter these objects was different. This model of cosmology, the overall
DR KEITH WHEELER / SCIENCE PHOTO LIBRARY
18 | NewScientist | 13 November 2010
coursing through our universe? A new study bolsters the idea – and paints a new view of the process of inflation, the exponential expansion that occurred moments after the big bang. The universe can be divided into two components: matter and radiation, which is seen as the cosmic microwave background (CMB). Much of the matter is in motion in a local sense – for example, our solar system is moving through the Milky Way. But according to the standard
matter component should not be moving in any particular direction relative to the CMB. Studies of the CMB show that Earth is moving in a particular direction with respect to the CMB. If this is all due to local movement, Earth should move with respect to distant cosmic objects at the same speed. But when Yin-Zhe Ma of the University of Cambridge and colleagues analysed data from supernovae and about 4500 galaxies, they found that Earth’s motion with respect to
suggests that they too are moving relative to the CMB, and hints at a bulk flow of matter, says the team (arxiv.org/abs/1010.4276v1). One controversial explanation given for earlier evidence of this flow was the tug of a second, distant universe. Ma’s team says a more likely scenario is that the process of inflation, credited with smoothing out the distribution of matter and light in the early universe and causing the two components to move at the same rate, did not quite finish the job. Nando Machado/Alamy
WINTER is just beginning in the northern hemisphere, but pieces of equipment at Harvard University are already covered in ice. It seems the clear solid can be used as a mask to build transistors more precisely. Daniel Branton and his colleagues placed carbon nanotubes onto a silicon wafer, cooled it to about -163 °C and sprayed it with water, causing an 80-nanometre-thick layer of ice to form. Then the researchers used an electron beam to carve away two squares of ice, exposing the tops of some nanotubes, and deposited a layer of palladium on top of this ice mask. Dipping the structure in alcohol melted the ice. The palladium layer above it then fell off, except in the two squares where the metal had stuck directly to the nanotubes. The resulting cluster of nanotubes, fused to two palladium electrodes, acted as a transistor (Nano Letters, DOI: 10.1021/nl050405n). The process resembles how computer chips are made, but in conventional lithography, a chemical is used as the mask. An advantage of “ice lithography” is that ice is transparent, so researchers could see where to remove sections of the mask so that the electrodes ended up precisely aligned with the nanotubes below. Ice is also cleaner, cheaper and gentler on the nanotubes.
Cosmic building site in hidden galaxies CALL it a cosmic construction site. Dust from frenetic star formation in the early universe completely shrouded some galaxies, blocking visible light from escaping into space. Now, the European Space Agency’s Herschel telescope has detected heat from five of these dusty galaxies, opening a window into the universe’s biggest stellar construction boom. Mattia Negrello of the Open University in Milton Keynes, UK, and colleagues found the galaxies by the glow of their heat at submillimetre wavelengths. Observations with ground-based telescopes then suggested that the galaxies’ light had been bent and magnified by the gravity of intervening galaxies on its way to Earth (Science, vol 330, p 800). Because the galaxies are magnified, they can be used to study how stars formed a few billion years after the big bang, when the stellar birth rate was about 100 times greater than it is today. The way their light has been bent can also be used to study the dark matter content of the intervening galaxies, says team member Asantha Cooray of the University of California, Irvine.
Zap your brain to improve your maths BAD at sums? Get muddled at the market? If so, you could benefit from a machine that improves your way with numbers by stimulating a particular area of the brain. Roi Cohen Kadosh at the University of Oxford and colleagues applied transcranial direct current stimulation (tDCS) – a way of changing the voltage across neurons that makes them more or less likely to fire – to the right parietal cortex while simultaneously using the opposite current to subdue activity in the left. While being zapped, volunteers were shown made-up symbols representing the numbers 1 to 9. Through a series of tests, they
gradually worked out which symbol stood for which number. After each session, the volunteers were asked to do calculations using the symbols. Those given tDCS learned the symbols faster and were better at the calculations than those given a sham procedure (Current Biology, DOI: 10.1016/ j.cub.2010.10.007). Six months later, those who had been given tDCS still did better than those who hadn’t. “tDCS affects neurotransmitters involved in learning, memory and plasticity, so we presume these are causing long-term changes in the brain,” says Cohen Kadosh.
For new stories every day, visit www.NewScientist.com/news
Add ice for more Mysterious matter flow suggests inflation was incomplete precise transistors IS THERE a bulk flow of matter these objects was different. This model of cosmology, the overall
DR KEITH WHEELER / SCIENCE PHOTO LIBRARY
18 | NewScientist | 13 November 2010
coursing through our universe? A new study bolsters the idea – and paints a new view of the process of inflation, the exponential expansion that occurred moments after the big bang. The universe can be divided into two components: matter and radiation, which is seen as the cosmic microwave background (CMB). Much of the matter is in motion in a local sense – for example, our solar system is moving through the Milky Way. But according to the standard
matter component should not be moving in any particular direction relative to the CMB. Studies of the CMB show that Earth is moving in a particular direction with respect to the CMB. If this is all due to local movement, Earth should move with respect to distant cosmic objects at the same speed. But when Yin-Zhe Ma of the University of Cambridge and colleagues analysed data from supernovae and about 4500 galaxies, they found that Earth’s motion with respect to
suggests that they too are moving relative to the CMB, and hints at a bulk flow of matter, says the team (arxiv.org/abs/1010.4276v1). One controversial explanation given for earlier evidence of this flow was the tug of a second, distant universe. Ma’s team says a more likely scenario is that the process of inflation, credited with smoothing out the distribution of matter and light in the early universe and causing the two components to move at the same rate, did not quite finish the job. Nando Machado/Alamy
WINTER is just beginning in the northern hemisphere, but pieces of equipment at Harvard University are already covered in ice. It seems the clear solid can be used as a mask to build transistors more precisely. Daniel Branton and his colleagues placed carbon nanotubes onto a silicon wafer, cooled it to about -163 °C and sprayed it with water, causing an 80-nanometre-thick layer of ice to form. Then the researchers used an electron beam to carve away two squares of ice, exposing the tops of some nanotubes, and deposited a layer of palladium on top of this ice mask. Dipping the structure in alcohol melted the ice. The palladium layer above it then fell off, except in the two squares where the metal had stuck directly to the nanotubes. The resulting cluster of nanotubes, fused to two palladium electrodes, acted as a transistor (Nano Letters, DOI: 10.1021/nl050405n). The process resembles how computer chips are made, but in conventional lithography, a chemical is used as the mask. An advantage of “ice lithography” is that ice is transparent, so researchers could see where to remove sections of the mask so that the electrodes ended up precisely aligned with the nanotubes below. Ice is also cleaner, cheaper and gentler on the nanotubes.
Cosmic building site in hidden galaxies CALL it a cosmic construction site. Dust from frenetic star formation in the early universe completely shrouded some galaxies, blocking visible light from escaping into space. Now, the European Space Agency’s Herschel telescope has detected heat from five of these dusty galaxies, opening a window into the universe’s biggest stellar construction boom. Mattia Negrello of the Open University in Milton Keynes, UK, and colleagues found the galaxies by the glow of their heat at submillimetre wavelengths. Observations with ground-based telescopes then suggested that the galaxies’ light had been bent and magnified by the gravity of intervening galaxies on its way to Earth (Science, vol 330, p 800). Because the galaxies are magnified, they can be used to study how stars formed a few billion years after the big bang, when the stellar birth rate was about 100 times greater than it is today. The way their light has been bent can also be used to study the dark matter content of the intervening galaxies, says team member Asantha Cooray of the University of California, Irvine.
Zap your brain to improve your maths BAD at sums? Get muddled at the market? If so, you could benefit from a machine that improves your way with numbers by stimulating a particular area of the brain. Roi Cohen Kadosh at the University of Oxford and colleagues applied transcranial direct current stimulation (tDCS) – a way of changing the voltage across neurons that makes them more or less likely to fire – to the right parietal cortex while simultaneously using the opposite current to subdue activity in the left. While being zapped, volunteers were shown made-up symbols representing the numbers 1 to 9. Through a series of tests, they
gradually worked out which symbol stood for which number. After each session, the volunteers were asked to do calculations using the symbols. Those given tDCS learned the symbols faster and were better at the calculations than those given a sham procedure (Current Biology, DOI: 10.1016/ j.cub.2010.10.007). Six months later, those who had been given tDCS still did better than those who hadn’t. “tDCS affects neurotransmitters involved in learning, memory and plasticity, so we presume these are causing long-term changes in the brain,” says Cohen Kadosh.