Science News Digest - 6th February 2012
In the science news this week, the world's largest interferometer is set to look to the skies, a giant prawn is found in the deep sea, how we're one step closer to graphene supercomputers, and finally… why male spiders will break off their sex organs all in the name of reproduction.
Four telescopes are better than one
Astronomers have created the world’s largest virtual telescope by linking four optical telescopes so that they work as one. The telescopes based at the Paranal Observatory in Chile, form the Very Large Telescope (VLT), which has a virtual mirror of 130m (424ft) in diameter.
Reported in the BBC, the telescope has gone through its scientific verification, meaning that the system can now begin to collect data. A previous attempt to link the four units failed last March, but the hope is that the VLT will now allow for a much more detailed look at the Universe compared to other systems that use just two or three telescopes.
The process of linking telescopes in this way is known as interferometry, and creates a telescope with a much larger viewing area than would be available from just one telescope.
The amount of light that a telescope can observe is restricted by the size of the mirror within it, and current production techniques limits the diameter of these mirrors due to their weight or because of the quality of the reflective surface. By linking a number of telescopes, this removes the issue of creating a large enough mirror, but then creates the problem of having to ensure that the telescopes communicate correctly.
The head of instrumentation at Paranal, Frederic Gonte, called the event a "milestone in our quest for uncovering secrets of the Universe".
"It's an extremely important step because now we know that we're ready to do real science," he told the BBC. "From now on, we'll be able to observe things we were not able to observe before."
The previous attempt to link the telescopes failed because of vibrations in the system and poor atmospheric conditions. This made the collected data useless but this time it appears the system is working in perfect harmony.
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"Supergiant prawn" found in the deep ocean
A species of giant amphipod have been found by scientists in the Kermadec Trench just north of New Zealand, reported The Telegraph.
The 11 inch amphipod resembles a giant prawn and was discovered by scientists from the University of Aberdeen and Wellington’s NIWA marine research institute.
Amphipods are normally just an inch long, so it was quite a surprise for the research team to find such a large one.
"It just goes to show that the more you look, the more you find," NIWA principal scientist Ashley Rowden said.
"For such a large and conspicuous animal to go unnoticed for so long is just testament to how little we know about life in New Zealand's most deep and unique habitat."
This is not the first giant amphipod to be found – a similar discovery was made near Hawaii in the 1980s – but it is yet to be established whether this latest catch is a new species or not.
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Graphene supercomputers one step closer
The highly conductive properties of graphene, a carbon sheet just one atom thick, could now be harnessed to make incredibly fast computer chips, reported New Scientist.
Following its discovery, graphene was heralded as the answer to improving computing power as it offers much less resistance to the flow of electrons than silicon does. However, this amazing property has yet to be utilised because it has also proven to be a hindrance.
In order to process and carry out calculations, computers need to turn the flow of electricity on and off in their circuits. Transistors regulate this flow of electrons by acting like gates to them, however creating a graphene-based transistor has been impossible thus far because the material allows for a leakage of electrons, even when the transistor is its “off” state.
The team, which first discovered graphene, have now come up with a solution to this leakage problem by sandwiching a layer of molybdenum disulphide between two layers of the carbon sheet. The molybdenum acts as an insulator, preventing electrons from passing from one graphene layer to another.
However, when a voltage is applied across the barrier the energy of the electrons is boosted, which allows for a quantum “tunnelling” effect, creating a current between the two layers. By varying the voltage, it is possible to turn the flow on and off, making the device act as a transistor.
This technique reduces the electron leakage by a factor of 10 when compared to previous graphene-based transistors. The team hopes that the leakage could be reduced even further by increasing the thickness of the molybdenum layer.
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And finally…
Spider castration could improve survival
It seems counter-intuitive, but it appears spiders that sacrifice their genitals during sexual intercourse do so to increase their chances of survival. It has long been known that some species of spider do this, but the reasons behind the self-castration had been a bit of a mystery.
But now, Daiqin Li, a behavioural ecologist from the National University of Singapore, may have the answer. Li’s team studied a species of orb-web spider called Nephilengys malabarensis, a species where the male is much smaller than the female and more often than not eaten by their partners during copulation, reported The Guardian.
Li’s team observed 25 virgin male spiders when put onto the webs of females. All the spiders mated, leaving 22 males with completely severed sex organs, or palps, and three with partially damaged genitals.
The arachnids were then dissected revealing that only a third of the spiders’ sperm had entered the females, with the rest left in the severed palps.
The scientists found that the longer the palp remained lodged in the female, the more sperm was transferred, thus increasing the chances of fertilisation. The broken palp also acted as an effective plug, meaning the female could not mate with another male.
What remains unclear is how the severed palps could continue to inseminate the female despite being detached from the male. However, it is believed that the spiders evolved this way in order to increase the chances of fertilisation even if the palps were broken off prematurely, or if the female decided to eat the male alive.
Four telescopes are better than one
Astronomers have created the world’s largest virtual telescope by linking four optical telescopes so that they work as one. The telescopes based at the Paranal Observatory in Chile, form the Very Large Telescope (VLT), which has a virtual mirror of 130m (424ft) in diameter.
Reported in the BBC, the telescope has gone through its scientific verification, meaning that the system can now begin to collect data. A previous attempt to link the four units failed last March, but the hope is that the VLT will now allow for a much more detailed look at the Universe compared to other systems that use just two or three telescopes.
The process of linking telescopes in this way is known as interferometry, and creates a telescope with a much larger viewing area than would be available from just one telescope.
The amount of light that a telescope can observe is restricted by the size of the mirror within it, and current production techniques limits the diameter of these mirrors due to their weight or because of the quality of the reflective surface. By linking a number of telescopes, this removes the issue of creating a large enough mirror, but then creates the problem of having to ensure that the telescopes communicate correctly.
The head of instrumentation at Paranal, Frederic Gonte, called the event a "milestone in our quest for uncovering secrets of the Universe".
"It's an extremely important step because now we know that we're ready to do real science," he told the BBC. "From now on, we'll be able to observe things we were not able to observe before."
The previous attempt to link the telescopes failed because of vibrations in the system and poor atmospheric conditions. This made the collected data useless but this time it appears the system is working in perfect harmony.
-----------------------------------------------
"Supergiant prawn" found in the deep ocean
A species of giant amphipod have been found by scientists in the Kermadec Trench just north of New Zealand, reported The Telegraph.
The 11 inch amphipod resembles a giant prawn and was discovered by scientists from the University of Aberdeen and Wellington’s NIWA marine research institute.
Amphipods are normally just an inch long, so it was quite a surprise for the research team to find such a large one.
"It just goes to show that the more you look, the more you find," NIWA principal scientist Ashley Rowden said.
"For such a large and conspicuous animal to go unnoticed for so long is just testament to how little we know about life in New Zealand's most deep and unique habitat."
This is not the first giant amphipod to be found – a similar discovery was made near Hawaii in the 1980s – but it is yet to be established whether this latest catch is a new species or not.
------------------------------------------
Graphene supercomputers one step closer
The highly conductive properties of graphene, a carbon sheet just one atom thick, could now be harnessed to make incredibly fast computer chips, reported New Scientist.
Following its discovery, graphene was heralded as the answer to improving computing power as it offers much less resistance to the flow of electrons than silicon does. However, this amazing property has yet to be utilised because it has also proven to be a hindrance.
In order to process and carry out calculations, computers need to turn the flow of electricity on and off in their circuits. Transistors regulate this flow of electrons by acting like gates to them, however creating a graphene-based transistor has been impossible thus far because the material allows for a leakage of electrons, even when the transistor is its “off” state.
The team, which first discovered graphene, have now come up with a solution to this leakage problem by sandwiching a layer of molybdenum disulphide between two layers of the carbon sheet. The molybdenum acts as an insulator, preventing electrons from passing from one graphene layer to another.
However, when a voltage is applied across the barrier the energy of the electrons is boosted, which allows for a quantum “tunnelling” effect, creating a current between the two layers. By varying the voltage, it is possible to turn the flow on and off, making the device act as a transistor.
This technique reduces the electron leakage by a factor of 10 when compared to previous graphene-based transistors. The team hopes that the leakage could be reduced even further by increasing the thickness of the molybdenum layer.
--------------------------------------------------
And finally…
Spider castration could improve survival
It seems counter-intuitive, but it appears spiders that sacrifice their genitals during sexual intercourse do so to increase their chances of survival. It has long been known that some species of spider do this, but the reasons behind the self-castration had been a bit of a mystery.
But now, Daiqin Li, a behavioural ecologist from the National University of Singapore, may have the answer. Li’s team studied a species of orb-web spider called Nephilengys malabarensis, a species where the male is much smaller than the female and more often than not eaten by their partners during copulation, reported The Guardian.
Li’s team observed 25 virgin male spiders when put onto the webs of females. All the spiders mated, leaving 22 males with completely severed sex organs, or palps, and three with partially damaged genitals.
The arachnids were then dissected revealing that only a third of the spiders’ sperm had entered the females, with the rest left in the severed palps.
The scientists found that the longer the palp remained lodged in the female, the more sperm was transferred, thus increasing the chances of fertilisation. The broken palp also acted as an effective plug, meaning the female could not mate with another male.
What remains unclear is how the severed palps could continue to inseminate the female despite being detached from the male. However, it is believed that the spiders evolved this way in order to increase the chances of fertilisation even if the palps were broken off prematurely, or if the female decided to eat the male alive.
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