Call me obsessive, but I’ve found the recent body of work studying the binary pulsar system compelling.
It’s great stuff and I doff my hat to all those Jodrell Bank and around the world who are involved. For those who’s curiosity isn’t satisfied by writings on this page (I can’t begin to imagine why!), this website has great videos and images that help to clear things up.
Enjoy.
Saturn’s tiny moon Daphnis making ripples in the rings last Saturday
From Riding with Robots. Details of the Cassini Mission can be found here.
CNN has come up trumps. This article about Louise Ciccone’s orbital aspirations is worth it just for the headline;
Lawmaker wants to shoot Madonna into space
…he’s not the only one…
If you were to take a jaunt 2000 light-years away towards the Puppis constellation, you’d find one of Astronomy’s most intriguing phenomena. Although only 20 kilometers each in diameter, the two neurton starts that make up the universe’s only observable double pulsar system provide the perfect playground in which to test Einstein’s General Theory of Relativity.
That’s just what an international team led by Prof. Michael Kramer at the UK’s Jodrell Bank Observatory have been up to.
The stars orbit each other once every 2.4 hours at the relatively miniscule distance of a million kilometers. With each more massive than our Sun, the gravitational force they exert on one another is enormous. As the two pirouette around each another, they emit pulses of radio signals that can be likened to the ticking of two highly accurate, astronomical clocks. Over the past three years, it is data collected from these pulses that has allowed researchers to put Einstein to the test.
“This is the most stringent test ever made of General Relativity in the presence of very strong gravitational fields – only black holes show stronger gravitational effects, but they are obviously much more difficult to observe”, says Kramer.
In addition to finding evidence of ‘gravitational waves’ and ‘time dilation’, of particular interest was the observation of a predicted effect known as ‘The Shapiro Delay’. With such a high gravitational field surrounding the double pulsar, space-time is warped. As radio pulses from one pulsar pass through the curved space-time encircling the other, they are delayed by about 90 millionths of a second. It is this measurement, published today in the journal Science, that is within 0.05% of Einstein’s predicted value.
“The double pulsar is really quite an amazing system. It not only tells us a lot about general relativity, but it is a superb probe of the extreme physics of super-dense matter and strong magnetic fields [and] is also helping us to understand the complex mechanisms that generate the pulsar’s radio beacons.” Prof. Kramer concludes, “We have only just begun to exploit its potential!”
With potable water becoming an ever more pressing issue on the global agenda, the World Bank appears to be showing increasing support for controversial dam-building projects. Having bowed to pressure from ecologists in the 90′s, the bank has, up until recently, steered clear of high profile damming projects, according to an article to be published this week in New Scientist magazine. However, things look set to change:
The World Bank is showing a growing enthusiasm for funding new large dams, especially in Africa. Yet according to a leading ecologist at an organisation part-funded by the bank, this policy threatens to drive parts of the world back into poverty.
Max Finlayson of the International Water Management Institute told the 2006 International River Symposium conference, held in Brisbane, Queensland, last week that many large dams exacerbate poverty by damaging the fisheries and wetlands on which the poorest people depend most. “A quarter of the world lives in river basins where the water is already fully or over-allocated,” Finlayson adds. New developments in these areas “will only take water from some users and give it to others”. He says investment should go instead into using water more efficiently.
The balance between ecology and economy has always been a tricky one, and as it stands, it looks like the situation won’t get any less complex, any time soon.
It’s the classic symptom of schizophrenia that has embedded itself deep within popular culture. Books, movies, even jokes are all found to reference ‘the voices in your head’. Far from being restricted to Hollywood’s serial killers, however, Dutch findings estimate that as many as 4% of the general population could be hearing voices, but that for many, it is a positive experience, and goes unreported.
A new study to be launched tomorrow on ‘World Hearing Voices Day’, hopes to investigate what makes certain people more vulnerable to negative experiences.
“We know that many members of the general population hear voices but have never felt the need to access mental health services; some experts even claim that more people hear voices and don’t seek psychiatric help than those who do.” says Aylish Campbell, from the University of Manchester group carrying out the research in the UK.
“In fact, many of those affected describe their voices as being a positive influence in their lives, comforting or inspiring them as they go about their daily business. We’re now keen to investigate why some people respond in this way while others are distressed and seek outside help.”
“If a person is struggling to overcome a trauma or views themselves as worthless or vulnerable, or other people as aggressive, they may be more likely to interpret their voices as harmful, hostile or powerful.
“Conversely, a person who has had more positive life experiences and formed more healthy beliefs about themselves and other people might develop a more positive view of their voices.
“People being treated for hearing voices are usually given medication in an attempt to eliminate the problem. By investigating the factors influencing how voices are experienced we hope to contribute to the development of psychological therapies to help people better understand and cope with their voices.”
Anyone in the Manchester area who would like to take part in this research is encouraged to email voicesresearch@hotmail.co.uk.
With one of the highest life expectancies in the world, it’s no wonder researchers are directing their scientific gaze at the Japanese. Newly published results suggest one key to the nation’s longevity may be its love affair with Green Tea.
A group at the Tohoku University School of Public Policy found that Green Tea consumption is inversely correlated with death. Over the course of 11 years, Dr. Shinichi Kuriyama led the study of 40,530 older adults. Those who drank more than five cups of Green Tea a day were found to have 16% less risk of death than people who consumed less than one cup a day.
The researchers are quick to point out that these results shed no light on how drinking Green Tea may be advantageous:
“Clinical trials are ultimately necessary to confirm the protective effect of green tea on mortality.”
Still, I’ll take any excuse for encouraging a 4 o’clock tea break on this side of the pond!
Filed under: Comment
It looks like Russia and China could be teaming up for future lunar missions, CNN.com reports. Representatives from both countries have been meeting in recent months to discuss increased collaboration. According to Anatoly Perminov, Russian Federal Space Agency chief,
“This is a serious and quite promising field of cooperation. In the past the Russian-Chinese cooperation have been mostly limited to the sales of Russian equipment, but now we are considering the development and implementation of joint projects.”
With such international efforts, perhaps manned missions will finally live up to the early promise of the mid 20th Century.
Filed under: Comment
Biking fans who know me personally may be tired of hearing my dogmatic insistence on the use of helmets. After the death of a school friend knocked from her bike, I’ve become a firm advocate of what I regard as a life-saver.
Dr. Ian Walker, from the University of Bath, UK, would probably disagree with me. He measured the distance from 2,500 overtaking vehicles using an ultrasonic sensor attached to his bike. While wearing a helmet, cars, buses and trucks passed, on average, 8.5 cm (3 1/3 inches) closer than when his skull was left unprotected.
“We know helmets are useful in low-speed falls, and so definitely good for children, but whether they offer any real protection to somebody struck by a car is very controversial,” says Dr. Walker, “either way, this study suggests wearing a helmet might make a collision more likely in the first place… The idea that helmeted cyclists are more experienced and less likely to do something unexpected would explain why drivers leave less space when passing.
“In reality, there is no real reason to believe someone with a helmet is any more experienced than someone without. The best answer is for different types of road user to understand each other better. Most adult cyclists know what it is like to drive a car, but relatively few motorists ride bicycles in traffic, and so don’t know the issues cyclists face.”
Dr. Walker also found that the average truck passed 19 centimetres (7.5 inches) closer, and the average bus 23 centimetres (9 inches) than cars. In addition, when wearing a long wig and appearing as a female, motorists gave him 14 centimetres (5.5 inches) extra while passing.
Interesting stuff, but not quite enough to make me give up my helmet just yet. Dr. Walker’s work fails to show causation. Who’s to say that his own riding style wasn’t affected by knowledge of the hypothesis, either consciously or unconsciously? It may be tricky to implement, but it would be more compelling if these results could be replicated in some kind of double-blind trial, with a larger and more variable group of cyclists.
Filed under: Comment, Sci@Night
Cities across the US are using the commonly found Bluegill fish as an early warning system to warn of chemical attacks on municipal water supplies, according to this Associated Press report.
Similar systems have been used in the mining industry for over a hundred years: the canaries have just learned to swim…