Science news digest - 23rd January 2013
In the science news this week, quadruple helix DNA seen in human cells, 2012 makes it into the top ten of hottest years on record, Kepler shuts down after navigational glitch, and finally…birds are anything but bass hunters.
Quadruple helix may be indicative of cancer
Scientists from Cambridge University have seen four-stranded DNA in human cells for the first time, reported the BBC. We usually think of DNA as being structured as a double helix, but this latest research has pinpointed DNA molecules in human cells made up of four strands, and more importantly, they may be related to cancer.
If this is the case, it could lead the way for new techniques to combat the disease.
"The existence of these structures may be loaded when the cell has a certain genotype or a certain dysfunctional state," said Prof Shankar Balasubramanian from Cambridge's department of chemistry.
"We need to prove that; but if that is the case, targeting them with synthetic molecules could be an interesting way of selectively targeting those cells that have this dysfunction."
2012 was one of the ten warmest years on record
Temperature data from NASA and the National Oceanic and Atmospheric Administration (NOAA) have shown that 2012 was among the 10 warmest years on record, rising above the long-term average for the 36th year in a row.
The data, compiled separately by both organisations, revealed the global surface temperature rose 1.03F above the long-term average, reported the Guardian.
NASA’s data puts 2012 as the ninth hottest year on record globally, whereas NOAA’s data makes it the tenth hottest year – this discrepancy is because the two agencies use different methods to analyse their data sets.
In both cases, scientists said that the 2012 global temperature records further confirm a pattern of global warming. The 21st century has seen annual temperature figures that sit among the 14 hottest years since records began in 1880.
"One more year of numbers isn't in itself significant," NASA climate scientist Gavin Schmidt said. "What matters is this decade is warmer than the last decade, and that decade was warmer than the decade before. The planet is warming. The reason it's warming is because we are pumping increasing amounts of carbon dioxide into the atmosphere."
Kepler glitch suspends its search for exoplanets
One of NASA’s most successful planet hunters, the Kepler space telescope, has had to suspend operations temporarily, after a problem with its orientation system, reported Wired.
The spacecraft orbits the Sun and sits more than 72 million kilometres away from the Earth. It has been put into safe mode for ten days in order to allow one of its manoeuvring wheels to recover – the system that orientates the telescope to keep it pointed at its stellar targets.
Kepler has been incredibly successful at picking up the tiny fluctuations in the light coming from distant stars – an indication that the star has a planetary system around it.
Since its launch in March 2009, it has boosted the number of confirmed exoplanets to over 850, but with another 2,740 still awaiting confirmation.
Even more surprisingly, Kepler has made all its discoveries in one small area of the sky, looking at just 160,000 stars.
When Kepler was launched, it had four manoeuvring wheels, but one failed in July 2012. Now a second wheel has started to show signs of failure, so in an attempt to save it, scientists have shut down the telescope to allow the lubricant on the wheel to spread around it.
Kepler mission manager Roger Hunter reported on 17 January: "Earlier this month during a semi-weekly contact with the spacecraft, the team detected an increase in the amount of torque required to spin one of the three remaining reaction wheels.
"This increase in friction occurred before the 11 January 2013 quarterly roll, and persisted after the spacecraft roll and several momentum desaturations of the reaction wheels. Increased friction over a prolonged period can lead to accumulated wear on the reaction wheel, and possible wheel failure.
"To minimise wheel friction, the team implemented several mitigations including increased operating temperatures, higher spin rates, and bi-directional operation following the failure of reaction wheel No 2 in July 2012."
He added: "Given the persistence of this recent event in reaction wheel No 4, the project team will place the Kepler spacecraft in a 'wheel rest' safe mode for a period of ten days beginning today. Science data collection will be stopped during this period and the spacecraft solar panel orientation will be aligned with the sun to maintain positive power for Kepler.
"This is similar to a normal safe mode configuration, but with thrusters maintaining attitude instead of reaction wheels. Resting the wheels provides an opportunity to redistribute internal lubricant, potentially returning the friction to normal levels."
Birds are turned off by bass
The sky may seem limitless, but in fact it would seem that space up there is at a premium. The number of birds that strike aircraft each year causes over a billion dollars’ worth of damage. Not only that, it’s extremely dangerous for the passengers aboard the aircraft, and it never ends well for the birds.
However, a new system has been developed by a company called Technology International, based in Louisiana in the USA, which is designed to scare aware any birds that find themselves in the path of oncoming planes, reported New Scientist.
The device transmits low frequency sound waves, which are undetectable to humans, but work as an effective deterrent to birds.
The system is currently being trialled and should be commercially available within two years.