Un'italiana trova acqua e metano su un pianeta extrasolare

ROMA - Per la prima volta nella storia dell’astronomia è stata individuata una molecola organica, il metano, nell’atmosfera di un pianeta esterno al sistema solare: un passo decisivo verso la possibile scoperta di forme di vita su mondi distanti . Il pianeta, che non ha ancora un nome ed è indicato con la sigla HD189733b, è un gigante gassoso simile a Giove, si trova a 63 anni luce dalla terra nella costellazione della “Vulpecula” (Volpetta), e si tratta dello stesso corpo celeste su cui a luglio lo stesso team che ha individuato il metano scoprì tracce di acqua, anche se sotto forma di vapor acqueo visti i 1.000 gradi di temperatura di HD189733b.

Co-autrice della scoperta, pubblicata oggi su Nature, la giovane astronoma italiana Giovanna Tinetti dell’University College di Londra, che sottolinea come in questo caso, «non si può pensare ad un’origine biologica del metano», perchè, «è altamente improbabile che delle mucche (fisiologiche fonti naturali di metano) possano sopravvivere li», ha ironizzato Tinetti. La ricercatrice ritiene che in ogni caso ci siano le basi per sperare di fare osservazioni analoghe su altri pianeti extrasolari più ospitali per la vita. La ricerca, condotta in collaborazione con Mark Swain e Gautam Vasisht, del Jet Propulsion Laboratory (Jpl) della Nasa, e stata effettuata grazie allo spettroscopio di Hubble.

Il pianeta, uno dei 271 finora individuati nell’universo, era stato scoperto nel 2005 quando, passando davanti alla sua stella, ne affievolì la luce del 3% circa. Al contrario dei pianeti terrestri, come il nostro, il pianeta HD 189733b è di grandi dimensioni e la sua massa è 1,15 volte quella di Giove. Si trova a soli 4,5 milioni di km dalla sua stella intorno alla quale compie un’orbita in 2,2 giorni. La Terra, al confronto, si trova a 150 milioni di km dal sole e persino Mercurio, il più vicino alla nostra stella, è distante 70 milioni di km.

Fonte - La Stampa, 20 Marzo 2008

"Chupacabra" test results update

Chupacabra update: Mystery grows with new test results

03:21 PM CST on Wednesday, February 6, 2008

By Joe Conger / KENS 5 Eyewitness News

Who isn't interested in their family tree?

But for Phylis Canion, it's a search for the lineage of a beast living under the oak trees of her Cuero ranch.

"The interest in the chupacabra has been overwhelming," said the Cuero rancher.

At least, that's the name the strange creature has been given in the last year.

Its DNA has been flown across the continent as Cuero residents search for a final answer about their mysterious, blood-sucking beast.

The much-anticipated results are back from experts at the University of California at Davis.

Last year, the KENS I-Team had scientists from Texas State University evaluate DNA from the animal Canion found.

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The animal was one of three peculiar, lavender-colored, dog-like animals Cuero residents found last July.

Results from Texas State University stated the animal is from the coyote family.

But Canion wanted to know more, so she sent more DNA, tooth and tissue samples, off to California.

Results from the University of California at Davis show the animal is in fact a mutt: on the mother's side it is part coyote.

"On the paternal side, it had Mexican wolf in it," said Canion.

Scientists from the University of California at Davis say they can't tell when the Mexican wolf heritage made its way into the gene pool.

It could be generations ago, but Canion believes the father's genes are important and can explain some of the odd characteristics of the creature.

"It was a hybrid, because it has this other breed in it," she said.

Canion is referring to the hairless, odd-colored skin originally thought to be caused by parasites or disease. Now, experts aren't so sure.

The Cuero rancher said she expects further testing to find out where all the hair has gone and why the animal, she says, seems to crave just blood from its victims.

"We still can't figure that one out," she said.

Meantime, an international media storm continues to descend on the small Texas town.

Italy's popular Voyager TV show spent an hour on the story of Canion and her creature.

Japan is sending a television crew this month, too, as the legend continues to grow.

E-mails and letters to Canion at her shop certainly haven't slacked, either.

"It may be quiet out here in rural Cuero, Texas, but the drama still continues. There are still sightings of the animal, and chickens? They keep disappearing, too. Some of it captured in footage by the Discovery Channel," she said.

They had cameras running, heat-seeking cameras, six cameras that ran for 31 days and took over a thousand shots, and in that it also picked this animal up.

That's a lot of images to comb through and may give even more insight into the creature's habits.

Together with the new DNA results, the Cuero rancher is reassured the animal is not a fluke of nature. Canion firmly believes a family of the Cuero creatures are living — and hunting — her property.

T-shirt sales of the chupacabra are still going strong, with more than 16,000 sold already.

There's even been legal action to keep some knock-offs from being sold on eBay where they were going for three times the price.

Mars Surface Too Acidic for Life To Exist

Martians may be more in the realm of science fiction than astronomical research.

Published On Friday, February 29, 2008 3:36 AM

By Kevin C. Leu

Crimson Staff Writer

NASA researchers, including one Harvard professor, have found that the surface of Mars has been too acidic to sustain life for the past four billion years, suggesting that Martians are more the realm of science fiction than astronomical research.

Clues found in the rocks by two NASA space rovers—Opportunity and Spirit—have led researches to conclude that the concentrations of minerals in Mars’s water makes the planet inhospitable for even the heartiest of organisms, according to Andrew Knoll, a professor of natural history in the Earth and planetary sciences department and a member of NASA’s Mars Exploration Rover science team.

“One particular iron sulfate mineral called jarosite forms only under strongly acidic conditions,” Knoll said. “Its identification in the Martian rocks provides a smoking gun for strongly acidic conditions.”

Knoll said that differences in size and distance from the sun caused Earth and Mars to become distinct early in their lives.

“About 3.8 billion years ago—the age of the sedimentary rocks collected by Opportunity—Earth had oceans, life, and an atmosphere capable of sustaining greenhouse warmth but without oxygen,” said Knoll, who added that the calculations on ancient water activity on Mars were performed by Harvard postdoctoral fellow Nicholas J. Tosca. “Mars was dry, acidic, and at least mildly oxidizing.”

Despite the evidence collected by the rovers, there still may be some opportunity to find evidence of life on Mars.

“Most of Mars remains unvisited by rovers, although orbiting satellites are providing good maps of surface conditions across the planet,” Knoll said.

Two rovers, the Phoenix lander and the Mars Science Laboratory, will be landing on Mars in the near future for evidence of the planet’s suitability for life.

The Phoenix lander, which is set to land on Mars on May 25, will be looking at a region farther to the north where there is permafrost.

“We’re going to places where there is kind of evidence that could support life and checking them out in greater detail,” said Diana Blaney, a member on the science team for the Phoenix lander. “Phoenix starts that process.”

Meanwhile, the Mars Science Laboratory is scheduled to leave Earth in the fall of 2009 and land on Mars in the summer of 2010. According to Joy A. Crisp, a Mars Science Laboratory scientist, it has capabilities that Spirit and Opportunity did not have, like the ability to analyze drilled powders from rocks for organic compounds.

“We will be looking at the oldest part of Mars, four to 4.5 billion years old Mars,” Crisp said. “This might be a different kind of environment that might be more suitable for life.”

—Staff Writer Kevin C. Leu can be reached at kleu@fas.harvard.edu.

Fonte - The Crimson