Peru meteorite may rewrite rules

A meteorite which ploughed into the Peruvian countryside last year should have shattered and dispersed long before reaching the ground.
That is the conclusion of scientists who have been examining samples of the space rock and the 15m-wide crater it dug out in Carancas last September.
The discovery of a water-filled hole, following reports of a fireball in the sky, made headlines around the world.
Now experts say the event challenges conventional theories about meteorites.
This has nothing to do with the mass panic that famously followed the impact; rather it has to do with the science of space impacts.
Usually, only meteorites made of metal survive the passage through Earth's atmosphere sufficiently intact to scoop out a crater.
But the object which came down in the Puno region of Peru was a relatively fragile stony meteorite. During the fiery descent through Earth's atmosphere, these are thought to fragment into smaller pieces which then scatter over a wide area.
Yet pieces of the estimated 1m-wide meteorite are thought to have stayed together during entry, hitting the ground as one.
Details of the work were unveiled at the Lunar and Planetary Science Conference in Houston, Texas.
Surprising speed
Peter Schultz told the conference that the meteorite was travelling at about 24,000km/h (15,000mph) at the moment of impact - much faster than would be expected.
"This just isn't what we expected," said Professor Schultz, from Brown University in Providence, US. "It was to the point that many thought this was fake. It was completely inconsistent with our understanding of how stony meteorites act."
Typically, fragments shoot off in many directions as the meteorite hurtles towards the ground - the so-called "pancake" model of atmospheric descent.
Professor Schultz believes fragments from the Carancas meteorite, which crashed to Earth on 15 September last year, may have stayed within the speeding fireball until they struck the ground.
This might have been due to the meteorite's high speed.
At the velocity it was travelling, fragments could not escape the "shock-wave" barrier which accompanies the meteorite's passage through the atmosphere.
Instead, the fragments may have reconstituted themselves into another shape, which made them more aerodynamic. Consequently, they encountered less friction during their plunge to Earth, holding together until they reached the ground.
"Although [the meteorite] is quickly broken up, it is behaving like a solid mass," Professor Schultz told the conference.
Dr Thomas Kenkmann, from Humboldt University in Berlin, Germany, offered an alternative view of the Carancas impact. His modelling of the event suggests it was probably caused by a meteorite travelling at low speed and a slanting angle.
Under this scenario, the space rock would have broken into just a few pieces rather than many - the largest of which would have gouged the crater.
Some scientists, however, remain doubtful of either interpretation. After his conference talk, Dr Kenkmann was pressed by one scientist on whether a magnetic survey of the crater had been carried out to look for signs of an iron, rather than a stony, projectile.
Fact and fiction
The crater is located on a dry riverbed near Lake Titicaca, on the border with Bolivia. The 3m-deep depression filled with water from below ground in the first 15-30 minutes after the impact.
At the time, scores of local people who visited the crater complained of headaches, vomiting and nausea. Some commentators had speculated that a chemical reaction might have released toxins such as sulphur and arsenic. But mass hysteria is thought to be the most likely explanation.
Professor Schultz said he hoped his work would "distinguish fact from fiction".
He commented: "Reports about arsenic, bubbling [of water in the crater] and sickness were probably overblown. People were frightened, but some were also afraid they were under attack from a nearby country."
Eyewitnesses reported a cloud of dust travelling outwards from the impact site after the meteorite fell.
Reports of numerous livestock deaths are believed to have been exaggerated, though the researchers confirm that a bull's horn was ripped off in the impact.
Professor Schultz added that the Carancas event raised the possibility there were many other small craters caused by stony meteorites which go unrecognised.
Large buried iron meteorites are easier to detect, while pieces of stony meteorite become intimately mixed with terrestrial soil.
"Maybe there are more of these things and we just don't recognise them because they're rock. When these things get pounded into cement, you won't see them," Professor Schultz explained.

Giant telescope opens both eyes

LBT has 10 times the resolution of the Hubble Space Telescope
Enlarge ImageThe world's most powerful optical telescope has opened both of its eyes.
Astronomers at the Large Binocular Telescope (LBT) in Arizona have released the first images taken using its two giant 8m diameter mirrors.
The detailed pictures show a spiral galaxy located 102 million light-years away from the Milky Way.
LBT has been 20 years in the making but promises to allow astronomers to probe the Universe further back in time and in more detail than ever before.
"The amount of time and work that was put into this project to reach the point where we are today is immense," said LBT Director Richard Green. "To see the telescope operational with both mirrors is a great feeling."
The $120m (£60m) telescope uses two mirrors in tandem to maximise the amount of light it gathers, which allows astronomers to look deep into the Universe.
Using two 8.4 m (27ft) mirrors will give LBT the equivalent light-gathering capacity of a single 11.8m (39ft) instrument and the resolution of a 22.8m (75ft) telescope.
Impressive detail
The resolution is 10 times greater than the space-based Hubble telescope, which has a 2.4m (8ft) mirror.
"The images that this telescope will produce will be like none seen before," said Professor Peter Strittmatter of the University of Arizona.
The first pictures are false-colour images of the spiral galaxy NGC 2770. The pictures show what is a flat disc of stars and glowing gas.

In graphics: LBTThe images - which take advantage of the telescope's ability to view the same point in space with multiple wavelengths of light - emphasise different features of the galaxy.
Combining ultraviolet and green light shows up clumpy regions of newly formed hot stars in the spiral arms, whilst a combination of red wavelengths highlights older, cooler stars.
The images were taken on 11 and 12 January but have only just now been released.
The LBT is located on Mount Graham in southeastern Arizona. It achieved "first light" with one mirror on 12 October 2005 when it imaged a spiral galaxy in the constellation of Andromeda.

South Korea swaps first astronaut

South Korea says its first astronaut will now be a female engineer, after Russian officials rejected the initial candidate over a breach of rules.
Yi So-yeon, 29, is to replace Ko San, 31, on a Russian flight to the International Space Station in April.
Russia's Federal Space Agency requested the change because Mr Ko broke training centre rules, a senior official said.
South Korean officials played down the breaches, which involved removing reading material from the centre.
On one occasion, Mr Ko sent a training book back to South Korea - something he said was by mistake.
On another, he received a book from a Russian colleague that he was not meant to read, said Lee Sang-mok of South Korea's Ministry of Education, Science and Technology.

Mr Ko was replaced at the request of Russia
"The Russians emphasised the importance of abiding by the rules, as even small mistakes can bring about grave consequences in space," Mr Lee said.
Mr Ko, who beat more than 36,000 other applicants to the position, has been training in Russia since last year.
He will now serve as the back-up astronaut when Ms Yi flies with two Russian cosmonauts to the International Space Station in early April.
Ms Yi will spend seven or eight days there, conducting a series of scientific tests.
The mission will make South Korea the sixth Asian country to put an astronaut in space.

Camera 'looks' through clothing

A camera that can "see" explosives, drugs and weapons hidden under clothing from 25 metres has been invented.
The ThruVision system could be deployed at airports, railway stations or other public spaces.
It is based on so-called "terahertz", or T-ray, technology, normally used by astronomers to study dying stars.
Although it is able to see through clothes it does not reveal "body detail" or subject people to "harmful radiation", according to the designers.
"It is totally and utterly passive - it receives only," said a spokesperson for Thruvision.
The portable camera, which has already been sold to the Dubai Mercantile Exchange and Canary Wharf in London, will be shown off at the Home Office scientific development branch's annual exhibition later this week.
Body glow
Unlike current security systems that use X-rays, the ThruVision system exploits terahertz rays, or T-rays.
This electromagnetic radiation is a form of low level energy emitted by all people and objects.
These are able to pass through clothing, paper, ceramics and wood but are blocked by metal and water.
The system works by collecting these waves and processing them to form an image which can reveal concealed objects.
"If I were to look at you in terahertz you would appear to glow like a light bulb and different objects glow less brightly or more brightly," said the firm's spokesperson.
"You see a silhouette of the form but you don't see surface anatomical effects."
In addition, the system does not involve any of the "harmful radiation associated with traditional X-ray security screening", according to the firm.
The company has made previous versions of the camera, but the T5000, as it is known, is the first that works both indoors and out.
The system exploits technology originally developed at the government owned Rutherford Appleton Laboratory (RAL) in Oxfordshire.
"Astronomers use T-ray cameras that can see through dust and clouds in space, revealing what lies beyond," explained Dr Liz Towns-Andrews, of the Science and Technology Facilities Council which runs RAL.
Other terahertz systems, developed by companies such as TeraView, are used to probe the structure of pharmaceutical compounds.

Blue Butterfly

A butterfly reserve in southern England has recorded a "spectacular resurgence" in the number of the winged insects, says Butterfly Conservation. Magdalen Hill Down, Hampshire, has seen a sharp rise in common blue butterflies (above), and chalkhill blues are up by as much as 700% in recent years.

World's first six-legged octopus discovered

(CNN) -- English marine experts have laid their hands on an octopus that's missing two of its own: a six-limbed creature that they have dubbed 'hexapus.'

Henry the 'hexapus' photographed by staff at Blackpool's Sea Life Centre, in northwest England.

Ordinarily, octopodes have eight arms and legs. And should they lose one or more in an accident, they can grow the limbs back.
Which is what makes 'Henry' -- as staffers at Blackpool Sea Life Centre in northwest England have dubbed their find -- so unique.
His missing limbs stem from a birth defect.
"If you look closer between the legs, there's webbing that attaches each of the arms together," John Filmer of the Sea Life Centre told CNN Tuesday. "You'd assume if he'd lost one of his legs in an accident, there would be space for an arm to grow back.
"But there's no space for two extra legs to grow back. That's just how he is."
Staffers called others zoos and aquariums and scoured the Internet to see if there were records of similar creatures.
"No one has ever heard of another case of a six-legged octopus," said display superviser Carey Duckhouse.
'Henry' was picked up from a local zoo along with seven other octopodes for a new exhibit at the center. No one noticed his missing legs until he attached himself to the inside of his glass tank.
They named him 'Henry' because it alliterated well with 'hexapus.'
"It has also been mentioned in the grapevine that he was named after King Henry the VIII who had six wives when he should have had eight," Filmer, the centre's marketing director, said.
Until Henry, the most famous six-legged octopus was one that appeared in a 1955 B-movie, 'It Came From Beneath The Sea.'
As was common of many science fiction movies of the era, the film was made on a shoestring budget -- and designers left off two legs from the creature because of budget contraints.
Octopuses are renowned for having three hearts, blue blood and the ability to alter their skin complexion in the blink of an eye.
But, said the center, "(e)ven these astonishing characteristics however are commonplace compared to Henry's unique tally in the leg department." E-mail to a friend

Photo shows avalanche on Mars

PASADENA, California (AP) -- A robotic spacecraft circling Mars has snapped the first image of a series of active avalanches near the planet's north pole, scientists said Monday.

A false color image from NASA taken February 19, 2008, shows an active avalanche on Mars.

The image, taken last month, reveals at least four avalanches of fine ice and dust breaking off from a steep cliff and settling on the slope below. The cascade kicked up massive debris clouds, with some measuring more than 590 feet across.
The landslides were spied by the Mars Reconnaissance Orbiter during a routine tracking of seasonal changes. The probe arrived at the planet in 2006.
It is rare for scientists to catch a natural event in action on the surface of Mars. Most of the landscape that has been recorded so far has not changed much in millions of years.
The avalanches occurred near the north pole and broke part of a 2,300-foot cliff.
"We were checking for springtime changes in the carbon-dioxide frost covering a dune field and finding the avalanches was completely serendipitous," Jet Propulsion Laboratory scientist Candice Hansen said in a statement.
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Scientists were unsure what set off the avalanches and whether they occur frequently or only during the spring. E-mail to a friend