Showing posts with label science news. Show all posts
Showing posts with label science news. Show all posts

Sunday, December 12, 2010

Now playing in a sky near you: Winter meteor show


Flaming rocks are hurtling toward the Earth upon the arrival of the annual Geminid meteor shower, one of the biggest of the year.

The peak of the week-long shower will come just before dawn Tuesday, but the shooting stars were visible across the world late this past weekend, says Rebecca Johnson, editor of StarDate magazine, which is published by the McDonald Observatory, the University of Texas research unit near Fort Davis, Texas.

Where skies are clear, the viewing will be best before dawn Tuesday. "It starts to get light an hour before sunrise, so any time before that is going to be a good time to look," Johnson says.

Those who'd rather stay up late than get up early might want to wait until the moon sets around midnight on each night during the shower.

"You can still see meteors when the moon is up, but it will be better when the moon has set," Johnson says.

The peak will hit at 6 a.m. ET on Tuesday, Johnson says.

"If you're brave enough to brave the frigid, arctic cold that's prevailing in most of the Eastern part of the country, that's when you'll see them," says Bill Cooke, an astronomer at NASA's Marshall Space Flight Center, in Huntsville, Ala.

Meteor showers can be unpredictable in the number of fiery paths sketched across the sky, but the Geminids are among the most consistent. They're expected to generate between 60 to 80 meteors an hour, "about one a minute," Cooke says.

Meteors aren't really falling stars. In the case of the Geminid shower, they're tiny pieces of debris breaking off an asteroid called 3200 Phaethon as it orbits the sun. Although the shower was first seen in the 1860s, the asteroid wasn't discovered until 1983.

The Geminids carry a whiff of mystery. Most well-known meteor showers, such as the Perseids and the Leonids, come from comets, which are "big, dirty snowballs," in Cooke's words.

When comets get near the sun, the heat turns the ice into gas, freeing some of that dirt, which is then pulled into Earth's orbit and falls through the atmosphere. As the debris burns up, it creates the brilliant streaks we see as meteors.

The Geminids come not from a comet but an asteroid, "a big hunk of rock," Cooke says.

Exactly why 3200 Phaethon has so much material trailing behind it to burn up in our atmosphere is unclear.

Even if 3200 Phaethon is a clump of rock bits, which is one kind of asteroid, the Geminids are many hundreds of years old, so those bits should have long since been lost, "and yet (they are) still throwing stuff off. It's a weird meteor shower," Cooke says.

For those who can't make it out Tuesday morning, the meteors will be visible tonight and a day or two after the peak, just not as plentiful.

It's "a great shower that many people never see" because they come during cold weather, Cooke says. "The Perseids get all the press. It's much nicer to be out on a warm August night than to be freezing your rear in December."



Read More

http://www.usatoday.com/tech/science/space/2010-12-13-Geminids13_ST_N.htm

Thursday, December 9, 2010

Commercial rocket launch, splashdown a success





The first of what NASA hopes will become a fleet of privately built rockets and capsules successfully launched from Cape Canaveral on Wednesday morning in a major test for the commercial space industry. After twice circling the globe, the capsule landed in the Pacific as planned three hours later.

The successful splashdown marks the first time that a commercial company launched a rocket and capsule into space and brought the spacecraft safely back to Earth.

The landing was announced on the Twitter account of Space Explorations Technologies Inc., or SpaceX, the start-up company that has pioneered the new era of commercial space travel. A recovery team was at the capsule - built to be reusable - within 20 minutes of splashdown, suggesting that it was on target for its landing.

The Falcon 9 rocket built by SpaceX was on its first full test flight. Its Dragon capsule was empty and unmanned, but plans are to fill it in the months ahead with cargo - and ultimately with astronauts - to transport to the International Space Station.

NASA's deputy administrator, Lori Garver, said after the splashdown that the administration was delighted by the success and that "the path to and from the space station is going to be this: a partnership between private companies and government to get the job done most effectively."

The flight is an important moment for President Obama and his administration's hopes to expand commercial space efforts in low-Earth orbit as a way to free up NASA funds for missions to send astronauts much deeper into space and ultimately to Mars.

SpaceX, founded in 2002 by Elon Musk and run from California, successfully launched a Dragon 9 rocket in June, but that test was done without a real capsule. Musk, who founded and sold the online payment company PayPal and is also behind development of the Tesla electric car, said before launch that he rated the chances for a successful mission at about 60 percent.

After the splashdown, Musk said he was in "semi-shock."

"There's so much that can go wrong and it all went right," Musk said. His next challenge is a Dragon capsule rendezvous with the space station that is scheduled for next year.

The Falcon 9 rocket is a pipsqueak compared with the space shuttle it will partially replace - measuring 157 feet with the capsule and weighing 735,000 pounds. The much larger shuttle was needed to fly parts up to the $100 billon international space station, but the fleet is being retired because of its age and because its job is largely done. Each shuttle flight costs about $1 billion, while the entire NASA contribution so far to SpaceX has been $253 million, according to NASA officials.


Read more:
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2010/12/08/MN0G1GNUHS.DTL#ixzz17bNf5g6y

Tuesday, November 30, 2010

Secret Military Mini-Shuttle Headed Back to Earth





A miniature robotic space shuttle launched from Cape Canaveral in April has completed a nine-month classified mission for the military and will be headed for a landing as early as Friday, Air Force officials said on Tuesday.

The vehicle, known as the Orbital Test Vehicle or X-37B, is expected to land at Vandenberg Air Force Base in California between Friday and Monday, depending on weather and technical considerations, the Air Force said in a statement.

The project, started by NASA in the late 1990s and later adopted by the military, is intended to test technologies for a next-generation space shuttle.

The military is looking at the space plane as a way to test new equipment, sensors and material in space, with the intention of incorporating successful technologies into satellites and other operational systems.

The Air Force imposed a news blackout on the X-37B's activities while in orbit, though it was tracked by amateur satellite-watchers throughout its nine-month mission.

The X-37B looks like a space shuttle orbiter, with a similar shape and payload bay for cargo and experiments.

But it measures 29 feet, 3 inches in length and has a 15-foot (4.5-meter) wing span, compared to the 122-foot (37-meter) orbiters with wing spans of 78 feet.

Unlike NASA's space shuttles, which can stay in orbit about two weeks, X-37B is designed to spend as long as nine months in space, then land autonomously on a runway.

The Air Force plans to fly its second X-37B vehicle this spring. The vehicles were built by Boeing Co's advanced research lab, Phantom Works.

Read More

http://abcnews.go.com/Technology/wireStory?id=12280571

Monday, November 29, 2010

Scientists find way to reverse aging in mice

Scientists in Boston have made an astounding discovery, taking aging mice and turning them young again, like tiny little Benjamin Buttons.




Scientists in Boston have made an astounding discovery, taking aging mice and turning them young again, like tiny little Benjamin Buttons.

Just like the title character in the Hollywood film version of "The Curious Case of Benjamin Button," the mice appeared to not only stop aging but grow younger.

Molecular biologist Dr. Ronald DePinho at Harvard Medical School in Boston was able to pull off the feat by playing with "telomeres" -- the protective DNA caps on the ends of our chromosomes.

The caps, which have long been implicated in aging, prevent our chromosomes from "fraying" and the genes inside them from "unravelling."

Scientists have long known that a little bit of our telomeres erodes each time our cells divide. Previous research has shown that people with longer telomeres tend to live longer, whereas those with shorter telomeres suffer more from age-related diseases, such as Alzheimer's.

A few years ago, DePinho and his research team devised a way to engineer mice so that they lacked a working copy of the gene that regulates the production of telomerase, which is an enzyme that strengthens telomeres and whose production declines over time.

Instead of dying at three years old, the genetically engineered mice died at about six months. By the time they died, they had become infertile, their coat hair had turned grey and they had developed age-related conditions such as osteoporosis.

DePinho wondered whether he could reverse the aging in the mice if they suddenly began making telomerase again.

So he took a group of engineered mice and added back the telomerase gene, but left it inactive. His team then allowed the mice to age for six months, until they were the equivalent of 80-year-old humans. They then gave the mice a drug that "switched on" the telomerase gene.

One month later, not only did the new production of telomerase stop the aging process in the mice, it appeared to actually undo the premature aging so that the mice became the physiological equivalent of young adults.

Even DePinho was surprised at how effective the experiment was.

"We expected to see a slowing or a stabilization of aging. Instead, what we found was a dramatic reversal in aging," he told CTV.

"The shrunken brains increased, new neurons were formed, the coat hair was restored to a new sheen."

DePinho notes that the treated mice went on to have a normal lifespan. They were simply healthier and biologically younger.

DePinto and his colleagues stress that the study was a "proof-of-concept" experiment, designed to show that changes to telomerase can affect aging. There are still many questions to answer before an experiment can be tried on humans.

For example, some research has shown that telomerase seems to help cancer tumours grow faster. DePinho says his team didn't observe any cancers in the mice, but then the telomerase was activated for only one month.

"This teaches us something fundamental about aging: that aged tissue -- even very aged tissue -- retains the ability to rejuvenate itself," he said.

DePinho says it's possible the method could be used to treat people with rare genetic premature aging syndromes. Whether the technique could help reverse normal aging still remains to be seen. Still, he says the findings were worth sharing and appear in the journal Nature.

"The results were so dramatic that we wanted to get them out to the research community as soon as possible so we could inspire the research community to move forward on these findings," DePinho said.


Read More

http://www.ctv.ca/CTVNews/Health/20101129/reversing-aging-mice-101129/

Thursday, November 25, 2010

Mammals Grew Big After Dinosaurs Died Off: Analysis





Mammals began to grow much larger after dinosaurs became extinct 65 million years ago, a new study suggests.

An international team of researchers analyzed the fossils of major groups of land mammals on each continent and found that their size increased from a maximum of about 10 kilograms (22 pounds) when they shared the Earth with dinosaurs to a maximum of 17 tonnes (18.7 U.S. tons) after dinosaurs became extinct.

"Basically, the dinosaurs disappear and all of sudden there is nobody else eating the vegetation. That's an open food source and mammals start going for it, and it's more efficient to be an herbivore when you're big," study co-author Jessica Theodor, an associate professor in the biological sciences department at the University of Calgary, said in a university news release.

The findings also show that the global ecosystem is able to reset itself relatively quickly.

"You lose dinosaurs 65 million years ago, and within 25 million years the system is reset to a new maximum for the animals that are there in terms of body size. That's actually a pretty short time frame, geologically speaking. That's really rapid evolution," Theodor said.


Read More
http://www.businessweek.com/lifestyle/content/healthday/646543.html

Thursday, November 18, 2010

Surprise at a Comet Visited by NASA: A Snowstorm



A peanut-shaped comet was spewing hundreds of tons of fluffy ice chunks every second as a NASA spacecraft swung by it two weeks ago.

“To me, this whole thing looks like a snow globe that you’ve simply just shaken,” Peter H. Schultz, a Brown University professor working on the mission, said Thursday during a news conference.

The Deep Impact spacecraft passed within 435 miles of Comet Hartley 2 two weeks ago, producing a series of photographs that showed bright jets coming off a rough surface.

What fascinated the mission scientists most was that the chunks of water ice in the jets were not being lifted off the surface by the force of water vapor heated by the sun, but rather by jets of carbon dioxide. This was the first time that such carbon dioxide jets had been observed at a comet.

Frozen carbon dioxide — dry ice — turns to carbon dioxide gas at a temperature of about minus 100 degrees Fahrenheit. Water ice stays frozen until it reaches much higher temperatures. Thus, it appears that the carbon dioxide gas on the comet is blowing apart the still-frozen water ice, along with dust particles, and sending it into space.

The scientists who analyzed the photos of Hartley 2 said that the frozen carbon dioxide within the comet must date from the beginnings of the solar system, because once it turns to gas, it disperses into space. “If it’s there, it’s primordial,” Lori M. Feaga, another member of the science team, said in an interview.

While the bright specks seen in the images ranged in size from golf balls to perhaps basketballs, the spacecraft did not suffer any damage as it flew through the storm at a speed of 27,000 miles an hour.

From the absorption of light by the specks, the scientists deduced that the chunks were not solid ice.

“We’re not seeing hail-size softballs or even ice cubes,” said Jessica M. Sunshine, a deputy principal investigator on the mission. “What we’re seeing are fluffy aggregates of very small pieces of ice. And so, they’re akin more to maybe a dandelion puff that is very empty air that can be easily broken apart.”

The carbon dioxide jets are coming off the two lobe-shaped ends of the comet, which is just three-quarters of a mile long. The spacecraft also found large amounts of water vapor — and not carbon dioxide — emanating from the central narrow waist region between the two lobes. This may mean that, for reasons not yet deciphered, the middle part of the comet does not contain much carbon dioxide, and thus the water ice in it can warm into vapor.

“We wouldn’t expect this at all,” Dr. Sunshine said. “This comet is doing two things at once.”

The Hartley 2 findings differ significantly from what the Deep Impact spacecraft found when it visited Comet Tempel 1 five years ago. At Tempel 1, Deep Impact found water vapor emissions similar to those coming from the middle of Hartley 2, but no carbon dioxide jets and no visible chunks of water ice.

After the Tempel 1 visit, NASA decided to reuse the spacecraft, which still had ample maneuvering fuel left, to head to a second comet. The mission was renamed Epoxi, an amalgamation of two acronyms: Epoch, or Extrasolar Planet Observation and Characterization, which has been using one of the spacecraft’s cameras to look at stars known to have planets, and Dixi, or Deep Impact Extended Investigation, for the second comet fly-by.

“It has emphasized how different comets are from one another and how understanding them is a much more complex problem than the rather simplistic approach I like to normally take,” said Michael F. A’Hearn, Epoxi’s principal investigator.

Read More

http://www.nytimes.com/2010/11/19/science/space/19comet.html?partner=rss&emc=rss


Light at night puts you in dark mood





A new study has shown that exposure to even dim light at night is enough to cause physical changes in the brains of hamsters that may be linked to depression.

Scientists found that female Siberian hamsters exposed to dim light every night for eight weeks showed significant changes in a part of the brain called the hippocampus.

This is the first time researchers have found that light at night, by itself, may be linked to changes in the hippocampus.

These alterations may be a key reason why the researchers also found that the hamsters exposed to dim light at night showed more depressive symptoms when compared to hamsters in a standard light-dark cycle.

"Even dim light at night is sufficient to provoke depressive-like behaviours in hamsters, which may be explained by the changes we saw in their brains after eight weeks of exposure," said Tracy Bedrosian, co-author of the study and doctoral student in neuroscience at Ohio State University.

The results were presented in San Diego at the annual meeting of the Society for Neuroscience.




Read more:
http://timesofindia.indiatimes.com/life-style/health-fitness/health/Light-at-night-puts-you-in-dark-mood/articleshow/6947098.cms#ixzz15dCf9E3C