Archive for the ‘Science & nature’ Category
A team of geophysicists has solved a 40-year-old mystery about Mars / NASA image
Source: NASA
A team of geophysicists has solved a 40-year-old mystery about Mars / NASA image
Source: NASA
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ASTRONOMERS said they could explain a nearly four-decade-old enigma surrounding rugged troughs and a chasm in the northern ice cap of Mars that could comfortably house the Grand Canyon.
The Red Planet’s northern cap measures around 1000 kilometres across, with layers of ice and dust stacked up to three kms deep. It also has two remarkable features that have puzzled scientists ever since they were exposed in detail by US probes almost 40 years ago.
One is the Chasma Boreale, a depression 500 kms long, up to 100 kms wide and two kms deep.
Many experts have surmised that the Chasma Boreale was created by volcanic action that melted the bottom of the ice sheet, triggering a flood that gouged out this mighty gash in Mars’ surface.
Another mystery is a spiral of troughs that radiate out through the polar cap, rather like a pinwheel. Its strange symmetry caused some experts to wonder whether the troughs were formed by a centrifugal force caused by the spinning of the planet.
According to this theory, ice that is closest to the pole moves slower than ice that is further from the pole. As a result, the semi-fluid ice tensed and broke, twisting into spirals as it did so.
But papers published in the journal Nature say both hunches are wrong – and the answer to the riddle is both simple and complex at the same time.
A team led by geophysicists Jack Holt and Isaac Smith of the University of Texas at Austin used radar data from a latter-day NASA scout, the Mars Reconnaissance Orbiter, that probed the cap’s subsurface topography.
The picture that emerges is a lost landscape that sweeps aside the idea of the northern polar cap as neat, cake-layered geology.
Instead, the subsurface is riddled with many complicated features, ranging widely in thickness and orientation. It points to an ancient process, over millions of years, by which the ice and dust stuck together while at they same time were sculpted by a powerful, persistent force: the Martian wind.
“Nobody realised that there would be such complex structures in the layers,” Dr Holt said.
“The layers record a history of ice accumulation, erosion and wind transport. From that we can recover a history of climate that’s much more detailed than anybody expected.”
The Chasma Boreale, far from being born in a catastrophic event, occurred through an aeons-long process, the scientists said. Wind eroded a gap in a base layer of soft sand and ice, rather like a river on Earth cuts its way through a valley, relentlessly exploiting the softest rock.
Further deposits of ice and dust then accumulated on either side of the gap, creating the slopes of the canyon.
As for the spiral troughs, the distinctive swirl was created by the Coriolis force, a well-known phenomenon on Earth in which winds are deflected by the planet’s spin.
Article source: http://www.news.com.au/technology/forty-year-mystery-of-mars-solved/story-e6frfro0-1225871836064?from=public_rss
TINY magnetic discs just a millionth of a metre in diameter could be used to kill cancer cells, according to a study.
Laboratory tests found the so-called “nanodiscs”, around 60 billionths of a metre thick, could be used to disrupt the membranes of cancer cells, causing them to self-destruct.
The discs are made from an iron-nickel alloy, which move when subjected to a magnetic field, damaging the cancer cells, according to the study, published in Nature Materials yesterday.
One of the study’s authors, Elena Rozhlova of Argonne National Laboratory in the United States, said subjecting the discs to a low magnetic field for around ten minutes was enough to destroy 90 per cent of cancer cells in tests.
In a commentary on the report, Jon Dobson of Keele University in Britain said antibodies could be used to direct the discs towards tumour cells.
“This provides an elegant and rapid technique for targeting tumour destruction without the side effects associated with systemic treatments such as chemotherapy,” Mr Dobson wrote.
Article source: http://www.news.com.au/breaking-news/world/magnetic-discs-could-kill-cancer/story-e6frfkui-1225805187798?from=public_rss
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A Google Earth image of Chile, where a massive earthquake has affected the Earth’s axis / Google Earth
Source: Supplied
THE earthquake that has killed over 700 Chileans and displaced over two million more has now caused our days to be shorter.
The earthquake that struck Chile measured at an 8.8 magnitude and put the entire Pacific on tsunami alert.
But scientists say the shifting in the tectonic plates has also shifted the Earth’s axis.
The Earth’s overall mass distribution has likely been altered which has made the length of a day 1.26 microseconds shorter, NASA scientists say.
“The axis about which the Earth’s mass is balanced should have moved by 2.7 milliarcseconds (about 8 centimetres or 3 inches),” NASA told Bloomberg.
“It’s what we call the ice-skater effect,” David Kerridge, head of Earth hazards and systems at the British Geological Survey in Edinburgh told Bloomberg.
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“As the ice skater puts when she’s going around in a circle, and she pulls her arms in, she gets faster and faster. It’s the same idea with the Earth going around if you change the distribution of mass, the rotation rate changes.”
The last time a day was shortened was after the 9.1 magnitude earthquake that sparked the Boxing Day tsunami.
That shift in the tectonic plates that lie underneath the ocean surface caused days to shorten by 6.8 microseconds, scientists say.
Article source: http://www.news.com.au/features/earth-days-039shortened039-by-earthquake/story-e6frflor-1225836120460?from=public_rss
The dinosaurs may have died because an invisible brown dwarf star is throwing snowballs at us / AFP
Source: AFP
AN invisible star responsible for the extinction of dinosaurs may be circling the Sun and causing comets to bombard the Earth, scientists said.
The brown dwarf – up to five times the size of Jupiter – could be to blame for mass extinctions that occur here every 26 million years, The Sun reports.
The star – nicknamed Nemesis by NASA scientists – would be invisible as it only emits infrared light and is incredibly distant. Nemesis is believed to orbit our solar system at 25,000 times the distance of the Earth to the Sun.
As it spins through the galaxy, its gravitational pull drags icy bodies out of the Oort Cloud – a vast sphere of rock and dust twice as far away as Nemesis.
These “snowballs” are thrown towards Earth as comets, causing devastation similar to the asteroid that wiped out the dinosaurs 65 million years ago.
Now NASA scientists believe they will be able to find Nemesis using a new heat-seeking telescope that began scanning the skies in January.
The Wide-Field Infrared Survey Explorer – expected to find a thousand brown dwarf stars within 25 light years of the Sun – has already sent back a photo of a comet possibly dislodged from the Oort Cloud.
Scientists’ first clue to the existence of Nemesis was the bizarre orbit of a dwarf planet called Sedna. Scientists believe its unusual, 12,000-year-long oval orbit could be explained by a massive celestial body.
Mike Brown, who discovered Sedna in 2003, said: “Sedna is a very odd object – it shouldn’t be there.
“The only way to get on an eccentric orbit is to have some giant body kick you – so what is out there?”
Professor John Matese, of the University of Louisiana at Lafayette, said most comets come from the same part of the Oort Cloud.
He added: “There is statistically significant evidence that this concentration of comets could be caused by a companion to the Sun.”
Article source: http://www.news.com.au/features/invisible-star-shooting-comets-at-earth/story-e6frflor-1225840140357?from=public_rss
How Sydney could look if the world ended in 2012. Picture: Sony Pictures Home Entertainment
Source: Supplied
How Bondi Beach could look if the world ended in 2012. Picture: Sony Pictures Home Entertainment
Source: Supplied
How Sydney, and the iconic Opera House, could look if the world ended in 2012. Picture: Sony Pictures Home Entertainment
Source: Supplied
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BETTER mark December 20, 2012 in your calendar, there’s a chance of showers and possibly the apocalypse.
Incredible images show what an Earth-ending event might look like if the world ends in 2012.
Massive tidal waves and ground-shattering earthquakes are just some of the things Aussies have to look forward to if Mayan predictions come true, according to Australian mythology expert Dr Julian Droogan.
Do you think the world will end? Tell us below.
Based on the ancient civilisation’s calendar, the planet is supposed to face a disaster that will destroy all of humanity, leaving an empty world for a new Earth to be created.
Mayans follow a calendar called the “Long Count”, based on the year in which the world was recreated from the last time it was cataclysmically destroyed, approximately 5123 years ago.
According to Dr Droogan, the Mayan gods, who he called “a nasty lot”, would bring down fire from heaven. But what happens from that point has been a point of conjecture for historians, and even the Mayans themselves.
“Some Mayans believed the world would end, while some others thought it would be a period of renewal,” he said.
While doom-saying is not exactly an exact science; the world failing to collapse around us at the end of the millennium or after the Y2K bug, Prof. Droogan says it’s a myth that will be prevalent for a long time.
But don’t be in too much of a hurry to get your bomb shelters and non-perishables ready, Dr Droogan believes we will make it past December 20, 2012 unharmed.
“I think we live in very concerning times. I think there’s a lot of alienating and there’s a lot of fear out there and that’s why prophecies such as the Mayan calendar are so prevalent,” he said.
“I think the fears are real, but I don’t think the world will necessarily end.”
But should humanity manage to survive this cataclysmic event, don’t fret. According to Dr Droogan, the next apocalyptic prediction is not due till 3100, when the Hindus believe the world will end.
Article source: http://www.news.com.au/features/look-out-it039s-the-end-of-the-world/story-e6frflor-1225842356810?from=public_rss
An academic says food portion sizes have grown by biblical proportions, as shown by the painting of the Last Supper / AP
Source: AP
WE’VE been overeating our way through ever-larger portions over the past 1000 years, a US study revealed after studying more than 50 paintings of the Biblical Last Supper.
The study, by a Cornell University professor and his brother who is a Presbyterian minister and a religious studies professor, showed that the sizes of the portions and plates in the artworks, which were painted over the past millennium, have gradually grown by between 23 and 69 per cent.
This finding suggests that the phenomenon of serving bigger portions on bigger plates, which pushes people to overeat, has also occurred gradually over the same time period.
“The last thousand years have witnessed dramatic increases in the production, availability, safety, abundance and affordability of food,” Brian Wansink, author of Mindless Eating: Why We Eat More Than We Think, said.
“We think that as art imitates life, these changes have been reflected in paintings of history’s most famous dinner.”
The researchers analysed 52 paintings depicting the Last Supper which were featured in the 2000 book Last Supper by Phaidon Press, and used computer-aided design technology to analyse the size of the main meals, or entrees, bread and the plates relative to the average size of the disciples’ heads.
The study found that, over the past 1000 years, the size of the main meal has progressively grown 69 per cent; plate size has increased 66 per cent and bread size by about 23 per cent.
The research, conducted with Mr Wansink’s brother, Craig Wansink, a professor of religious studies at Virginia Wesleyan College, was published in the April edition of The International Journal of Obesity.
Article source: http://www.news.com.au/features/jesus-returns-for-last-supper-upsize/story-e6frflor-1225844639953?from=public_rss
Stephen Hawking says to a mathematician, the possibility of alien life is
a “perfectly rational” concept / AP
Source: AP
MANKIND must look to colonize outer space within the next century or it will become extinct, renowned British astrophysicist Stephen Hawking warned the Big Think website yesterday.
Professor Hawking said the human race is entering an increasingly dangerous period of its history.
“Our population and our use of the finite resources of planet Earth, are growing exponentially, along with our technical ability to change the environment for good or ill,” he said.
“But our genetic code still carries the selfish and aggressive instincts that were of survival advantage in the past. It will be difficult enough to avoid disaster in the next hundred years, let alone the next thousand or million.
“Our only chance of long-term survival, is not to remain inward looking on planet Earth, but to spread out into space. We have made remarkable progress in the last hundred years. But if we want to continue beyond the next hundred years, our future is in space.”
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Hawking cited the Cuban missile crisis in 1963 as one of many times in the past when mankind’s survival has been a question of touch and go.
“The human race shouldn’t have all its eggs in one basket, or on one planet. Let’s hope we can avoid dropping the basket until we have spread the load,” he said.
Hawking’s comments come after he warned in April of the dangers of communicating with aliens.
He told the Discovery Channel that extra-terrestrials are almost certain to exist – and humanity should be wary of contact in case they are not friendly.
Hawking’s research and his best-seller “A Brief History of Time” have made him an academic celebrity and in 2009 he was awarded the Presidential Medal of Freedom, the highest civilian award in the US.
The 68-year-old has neuro-muscular dystrophy, a condition that has left him almost completely paralyzed.
Article source: http://www.news.com.au/features/colonise-space-or-else-face-039extinction039/story-e6frflor-1225903485158?from=public_rss
Alan Rickman, Rupert Grint and Daniel Radcliffe wear capes in Harry Potter and the Goblet of Fire, but how do you show a picture of something invisible?
Source: News Limited
US-based scientists claim to have reached a significant milestone in their efforts to create the world’s first invisibility cloak.
Researchers at Boston University and Tufts University, both based in Massachusetts, have developed a new silk-based material that can bend light around solid objects, Discovery News said.
So far the “meta-material” only works for the terahertz range of light, which is outside the visible spectrum.
But the team are convinced it could one day be refined to produce the sort of miraculous garment more reminiscent of something from a Harry Potter movie.
The silk’s special powers come from a pattern of tiny gold devices, known as “split ring resonators,” weaved into the fabric.
The resonators, 10,000 of which are embedded into square centimeter, can absorb, reflect or bend light at a particular wavelength.
While the potential for an invisibility cloak has fascinated humanity for centuries, the greatest impact of the new device could be felt in the medical world, researchers suggest.
Radiologists, for example, could use it to examine hard-to-access parts of the body by effectively “cloaking” any organs that get in the way.
Experts point out that a “meta-material” that works in the terahertz range is nothing new, however adapting it to silk is significant because the human body does not reject the fabric.
“This means it can be implanted directly into the human body without reactions,” Fiorenzo Omenetto, one of the scientists based at Tufts University, told Italian news agency ANSA.
Article source: http://www.news.com.au/features/boffins-focus-on-first-invisibility-cloak/story-e6frflor-1225904784732?from=public_rss
A scientist warns Australia is due a volcanic explosion with hundreds of volcanoes potentially due to erupt/ AP
Source: AP
AS if bushfires, drought and floods aren’t enough, Australians have now been warned to watch out for volcanoes.
A scientist has warned an eruption is “well overdue” and says there are hundreds of volcanoes that could cause trouble, from South Australia and Victoria through to Queensland.
But it doesn’t seem too urgent – an eruption is already 3000 years overdue.
Melbourne geologist Bernie Joyce wants “eruption response plans” drawn up. He says there are 400 volcanoes in Victoria and South Australia, and almost as many in Queensland.
“A significant eruption seems well overdue,” said Prof Joyce, who has been associated with the University of Melbourne.
“These geo-hazards are real and they must be given much more focus by emergency management authorities.
“We can’t say with 100 per cent certainty that a significant volcano will strike tomorrow, next week, next year, or even 100 years down the track.”
Prof Joyce takes a long-term view, as geologists tend to do. He says there has been a volcanic eruption about every 2000 years in Australia, but the last one was 5000 years ago.
Prof Joyce will on Thursday be awarded the Geological Society of Australia (Victoria Division)’s Selwyn Medal.
Article source: http://www.news.com.au/features/volcano-we039re-3000-years-overdue/story-e6frflor-1225777277029?from=public_rss
THE winners of this year’s Australian Research Council’s competitive grants scheme have been announced, with 1145 projects to receive $394 million.
The Federal Government will hand out $760,000 to the University of New South Wales to research the effects of parents providing alcohol to children.
The Australian National University will receive $347,000 to study the ancestors of the recently discovered species of hominids, Homo floresiensis (also known as hobbits), in Indonesia.
La Trobe University will receive $220,000 over three years to help develop a new type of honey bee with no sting.
Nine indigenous Australian researchers will share $1.8 million in grants through the Discovery Indigenous Researchers Development Scheme to further research areas of importance to indigenous Australia.
NSW researchers were the big winners, claiming over $133 million in grants, followed by Victoria $103 million, Queensland $61 million, the ACT $40 million, WA $27 million, SA $21 million, Tasmania $4 million and the Northern Territory with $1.5 million.
Science Minister Kim Carr announced the funding today.
“The research that is being supported will lead to the discovery of new ideas and the advancement of knowledge that will help Australia tackle current and future economic, health and environmental challenges,” he said.
Article source: http://www.news.com.au/breaking-news/national/sting-free-honey-bee-gets-federal-funding/story-e6frfku9-1225791444768?from=public_rss
