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Lizards may be made smarter by warming world
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Detlev van Ravenswaay/spl
IF YOUR mind boggles at the billions and billions of stars in our galaxy, read on: every star may harbour a planet, giving us billions and billions of those too. About 700 extrasolar planets have been found in the Milky Way, a small number compared with the number of stars present. To find out whether such planets are truly rare or just hard to find, Arnaud Cassan of the Pierre and Marie Curie University in Paris, France, and colleagues turned to gravitational microlensing, in which one star focuses the light from a more distant star. The technique can reveal planets orbiting the nearer star if it is up to 20,000 light years from Earth, much farther than other techniques. The researchers studied six years of microlensing data and estimated that extrasolar planets are the rule rather than the exception, with each star in the galaxy hosting an average of 1.6 planets (Nature, DOI: 10.1038/nature10684). Meanwhile, William Welsh of San Diego State University in California and colleagues studied 750 stars observed by NASA’s Kepler satellite. They reckon several million planets in our galaxy orbit two stars, like the Star Wars planet Tatooine (Nature, DOI: 10.1038/nature10768). “The more carefully we look, the more [planets] we find,” says Welsh.
Thinnest silicon-chip wires refuse to go quantum NOT everything is weird at the nanoscale: wires just a few atoms wide can display ordinary electrical properties. That bodes well for conventional computers but could be bad news for hopedfor, super-fast quantum ones. It’s getting harder for chipmakers to stick to Moore’s law, which holds that the density of transistors a normal chip holds will double about every two years. This is because the resistance of a chip’s metal interconnects soars as they thin. Quantum effects can also disrupt ordinary electrical
properties because of the wave behaviour of electrons. Now, Michelle Simmons of the University of New South Wales in Sydney, Australia, and colleagues have taken a silicon chip and etched into it channels to act as wires just 1.5 nanometres wide that conducted electricity nearly as well as the interconnects in conventional microprocessors. The trick was to fill the channels with phosphorus, whose electrons moved freely to conduct electricity. When the team built wires of different lengths, they followed
the non-quantum Ohm’s law, which states that a wire’s resistance increases in step with its length (Science, DOI: 10.1126/ science.1214319). One explanation is that the high density of electrons caused them to scatter off each other, destroying their delicate quantum state. The result is a boon for evertinier computing devices. It might also be good news for quantum computers, as they require nanoscale wires. However, the lack of quantum behaviour also cools hopes for this technology. OMIKRON/SPL
Milky Way brims with planets
The future’s bright for warmer lizards WHEN the heat is on, lizards become smarter – potentially giving them a competitive edge as the world warms. Previous research has shown that scincid lizards (Bassiana duperreyi) grow larger if their eggs are incubated at higher temperatures. Joshua Amiel and colleagues at the University of Sydney, Australia, wanted to see if bigger lizards also make better learners, so they incubated nine eggs in cold conditions – 8.5 to 23.5 °C – and 12 in warm conditions – 14.5 to 29.5 °C. Once hatched, the lizards were put in plastic containers equipped with two hideouts, one blocked off with Plexiglass and the other fully accessible. The researchers, playing predators, scared the lizards by touching their tails with a paintbrush and recorded where the lizards went. After 16 trials, five of the nine cold-incubated lizards still headed for the inaccessible hideout. Just one of the 12 warm-incubated lizards made the same mistake (Biology Letters, DOI: 10.1098/ rsbl.2011.1161). “Climate change might not be so bad for these guys,” says Amiel.
Laser shone in eye tracks retina cells THE cone cells that help give us our colourful view of the world have been recorded growing in real-time in a living person’s eye. Cone cells in the retina each carry a stack of membranous discs: as they grow they shed older discs and generate new ones. An imbalance in the process can lead to blindness. Ravi Jonnal and colleagues at Indiana University in Bloomington have found a way to measure cone-cell growth by reflecting part of a laser beam off the cells within the eye of a healthy volunteer. Another part of the laser beam is reflected
off a mirror a set distance away. When the two beams recombine, the pattern of interference allows the team to work out the position of each disc in the cone cell. Taking measurements over several hours allowed Jonnal’s team to track each disc, revealing that the cells grow at roughly 150 nanometres each hour (Biomedical Optics Express, DOI: 10.1364/boe.3.000104). Fred Fitzke of University College London is impressed. “This could lead to major advances in preventing the progress of some of the leading causes of blindness,” he says.
14 January 2012 | NewScientist | 15
Detlev van Ravenswaay/spl
IF YOUR mind boggles at the billions and billions of stars in our galaxy, read on: every star may harbour a planet, giving us billions and billions of those too. About 700 extrasolar planets have been found in the Milky Way, a small number compared with the number of stars present. To find out whether such planets are truly rare or just hard to find, Arnaud Cassan of the Pierre and Marie Curie University in Paris, France, and colleagues turned to gravitational microlensing, in which one star focuses the light from a more distant star. The technique can reveal planets orbiting the nearer star if it is up to 20,000 light years from Earth, much farther than other techniques. The researchers studied six years of microlensing data and estimated that extrasolar planets are the rule rather than the exception, with each star in the galaxy hosting an average of 1.6 planets (Nature, DOI: 10.1038/nature10684). Meanwhile, William Welsh of San Diego State University in California and colleagues studied 750 stars observed by NASA’s Kepler satellite. They reckon several million planets in our galaxy orbit two stars, like the Star Wars planet Tatooine (Nature, DOI: 10.1038/nature10768). “The more carefully we look, the more [planets] we find,” says Welsh.
Thinnest silicon-chip wires refuse to go quantum NOT everything is weird at the nanoscale: wires just a few atoms wide can display ordinary electrical properties. That bodes well for conventional computers but could be bad news for hopedfor, super-fast quantum ones. It’s getting harder for chipmakers to stick to Moore’s law, which holds that the density of transistors a normal chip holds will double about every two years. This is because the resistance of a chip’s metal interconnects soars as they thin. Quantum effects can also disrupt ordinary electrical
properties because of the wave behaviour of electrons. Now, Michelle Simmons of the University of New South Wales in Sydney, Australia, and colleagues have taken a silicon chip and etched into it channels to act as wires just 1.5 nanometres wide that conducted electricity nearly as well as the interconnects in conventional microprocessors. The trick was to fill the channels with phosphorus, whose electrons moved freely to conduct electricity. When the team built wires of different lengths, they followed
the non-quantum Ohm’s law, which states that a wire’s resistance increases in step with its length (Science, DOI: 10.1126/ science.1214319). One explanation is that the high density of electrons caused them to scatter off each other, destroying their delicate quantum state. The result is a boon for evertinier computing devices. It might also be good news for quantum computers, as they require nanoscale wires. However, the lack of quantum behaviour also cools hopes for this technology. OMIKRON/SPL
Milky Way brims with planets
The future’s bright for warmer lizards WHEN the heat is on, lizards become smarter – potentially giving them a competitive edge as the world warms. Previous research has shown that scincid lizards (Bassiana duperreyi) grow larger if their eggs are incubated at higher temperatures. Joshua Amiel and colleagues at the University of Sydney, Australia, wanted to see if bigger lizards also make better learners, so they incubated nine eggs in cold conditions – 8.5 to 23.5 °C – and 12 in warm conditions – 14.5 to 29.5 °C. Once hatched, the lizards were put in plastic containers equipped with two hideouts, one blocked off with Plexiglass and the other fully accessible. The researchers, playing predators, scared the lizards by touching their tails with a paintbrush and recorded where the lizards went. After 16 trials, five of the nine cold-incubated lizards still headed for the inaccessible hideout. Just one of the 12 warm-incubated lizards made the same mistake (Biology Letters, DOI: 10.1098/ rsbl.2011.1161). “Climate change might not be so bad for these guys,” says Amiel.
Laser shone in eye tracks retina cells THE cone cells that help give us our colourful view of the world have been recorded growing in real-time in a living person’s eye. Cone cells in the retina each carry a stack of membranous discs: as they grow they shed older discs and generate new ones. An imbalance in the process can lead to blindness. Ravi Jonnal and colleagues at Indiana University in Bloomington have found a way to measure cone-cell growth by reflecting part of a laser beam off the cells within the eye of a healthy volunteer. Another part of the laser beam is reflected
off a mirror a set distance away. When the two beams recombine, the pattern of interference allows the team to work out the position of each disc in the cone cell. Taking measurements over several hours allowed Jonnal’s team to track each disc, revealing that the cells grow at roughly 150 nanometres each hour (Biomedical Optics Express, DOI: 10.1364/boe.3.000104). Fred Fitzke of University College London is impressed. “This could lead to major advances in preventing the progress of some of the leading causes of blindness,” he says.
14 January 2012 | NewScientist | 15