Warp Drive May Be More Feasible Than Thought, Scientists Say

HOUSTON — A warp drive to achieve faster-than-light travel — a concept popularized in television's Star Trek — may not be as unrealistic as once thought, scientists say.

A warp drive would manipulate space-time itself to move a starship, taking advantage of a loophole in the laws of physics that prevent anything from moving faster than light. A concept for a real-life warp drive was suggested in 1994 by Mexican physicist Miguel Alcubierre, however subsequent calculations found that such a device would require prohibitive amounts of energy.

Now physicists say that adjustments can be made to the proposed warp drive that would enable it to run on significantly less energy, potentially brining the idea back from the realm of science fiction into science.

"There is hope," Harold "Sonny" White of NASA's Johnson Space Center said here Friday (Sept. 14) at the 100 Year Starship Symposium, a meeting to discuss the challenges of interstellar spaceflight.

Warping space-time

An Alcubierre warp drive would involve a football-shape spacecraft attached to a large ring encircling it. This ring, potentially made of exotic matter, would cause space-time to warp around the starship, creating a region of contracted space in front of it and expanded space behind. [Star Trek's Warp Drive: Are We There Yet? | Video]

Meanwhile, the starship itself would stay inside a bubble of flat space-time that wasn't being warped at all.

"Everything within space is restricted by the speed of light," explained Richard Obousy, president of Icarus Interstellar, a non-profit group of scientists and engineers devoted to pursuing interstellar spaceflight. "But the really cool thing is space-time, the fabric of space, is not limited by the speed of light."

With this concept, the spacecraft would be able to achieve an effective speed of about 10 times the speed of light, all without breaking the cosmic speed limit.

The only problem is, previous studies estimated the warp drive would require a minimum amount of energy about equal to the mass-energy of the planet Jupiter.

But recently White calculated what would happen if the shape of the ring encircling the spacecraft was adjusted into more of a rounded donut, as opposed to a flat ring. He found in that case, the warp drive could be powered by a mass about the size of a spacecraft like the Voyager 1 probe NASA launched in 1977.

Furthermore, if the intensity of the space warps can be oscillated over time, the energy required is reduced even more, White found.

"The findings I presented today change it from impractical to plausible and worth further investigation," White told SPACE.com. "The additional energy reduction realized by oscillating the bubble intensity is an interesting conjecture that we will enjoy looking at in the lab."

Laboratory tests

White and his colleagues have begun experimenting with a mini version of the warp drive in their laboratory.

They set up what they call the White-Juday Warp Field Interferometer at the Johnson Space Center, essentially creating a laser interferometer that instigates micro versions of space-time warps.

"We're trying to see if we can generate a very tiny instance of this in a tabletop experiment, to try to perturb space-time by one part in 10 million," White said.

He called the project a "humble experiment" compared to what would be needed for a real warp drive, but said it represents a promising first step.

And other scientists stressed that even outlandish-sounding ideas, such as the warp drive, need to be considered if humanity is serious about traveling to other stars.

"If we're ever going to become a true spacefaring civilization, we're going to have to think outside the box a little bit, were going to have to be a little bit audacious," Obousy said.

You can follow SPACE.com assistant managing editor Clara Moskowitz on Twitter @ClaraMoskowitz. Follow SPACE.com on Twitter @Spacedotcom. We're also on Facebook & Google+.

Copyright 2012 SPACE.com, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

View the original article here

T. rex bigger than thought, and very hungry

Visitors watch a full body scan of a Tyrannosaurus rex skeleton nicknamed ''Sue''.

Credit: Reuters/Handout/The Field Museum

By Ben Hirschler

LONDON | Wed Oct 12, 2011 9:39pm EDT

LONDON (Reuters) - Tyrannosaurus rex grew faster and weighed more than previously thought, suggesting the fearsome predator would have been a ravenous teen-ager, researchers said Wednesday.

Using three-dimensional laser scans and computer modeling, British and U.S. scientists "weighed" five T. rex specimens, including the Chicago Field Museum's "Sue," the largest and most complete T. rex skeleton known.

They concluded that Sue, who roamed the Great Plains of North America 67 million years ago, would have tipped the scales at more than 9 tons, or some 30 percent more than expected.

Intriguingly, the smallest and youngest specimen weighed less than thought, shedding new light on the animals' biology and indicating that T. rex grew more than twice as fast between 10 and 15 years of age as suggested in a study five years ago.

"At their fastest, in their teenage years, they were putting on 11 pounds or 5 kilograms a day," John Hutchinson of the Royal Veterinary College in London told Reuters.

"Just think how much meat that is. That's a hell of a lot of cheeseburgers ... it's a whole lot of duck-billed dinosaurs they needed to be chowing down on."

Hadrosaurs or duck-billed dinosaurs were common plant-eaters that lived alongside T. rex, making them an obvious meal for the giant meat-eaters.

A huge appetite means T. rex would have needed extensive territory and they were probably relatively rare. Their rapid teenage growth spurt also suggests they must have had a high metabolic rate, fuelling the idea they were warm-blooded.

A large body mass would have come at the expense of agility and the lower-leg muscles of T. rex were not as proportionately large as those of modern birds, indicating a top speed of about 10-25 miles per hour. "It's not super-fast but they were no slouches," Hutchinson said.

The latest research, published online in the journal PLoS ONE, adds to the body of evidence that has made T. rex among the most intensively studied of all dinosaurs.

The researchers, led by Hutchinson and Peter Makovicky of the Field Museum, used scans of skeletons to build digital models and then added flesh using the structure of soft tissues in birds and crocodiles as a guide.

(Reporting by Ben Hirschler; Editing by Matthew Jones)

View the original article here

Benefit of mammograms even greater than thought

A doctor exams mammograms, a special type of X-ray of the breasts, which is used to detect tumours as part of a regular cancer prevention medical check-up at a clinic in Nice, south eastern France January 4, 2008.

Credit: Reuters/Eric Gaillard

By Julie Steenhuysen

CHICAGO | Tue Jun 28, 2011 1:35am EDT

CHICAGO (Reuters) - The longest-running breast cancer screening study ever conducted has shown that regular mammograms prevent deaths from breast cancer, and the number of lives saved increases over time, an international research team said on Tuesday.

The study of 130,000 women in two communities in Sweden showed 30 percent fewer women in the screening group died of breast cancer and that this effect persisted year after year.

Now, 29 years after the study began, the researchers found that the number of women saved from breast cancer goes up with each year of screening.

"We've found that the longer we look, the more lives are saved," Professor Stephen Duffy of Queen Mary, University of London, whose study was published in the journal Radiology, said in a statement.

Dr. Stamatia Destounis, a radiologist at Elizabeth Wende Breast Care in Rochester, New York, who was not involved in the study, said radiologists have been quoting results of the Swedish study for years and the new findings show breast cancer screening is "even more of a benefit than we understood."

She said sweeping changes in the U.S. screening guidelines two years ago that scaled back recommendations on breast cancer screening caused a lot of confusion among doctors and patients about the benefits of mammograms.

"We've had to do a lot of education of the patients and their doctors. This will help for that," Destounis said.

In the study, women were divided into two groups, one that received an invitation to have breast cancer screening and another that received usual care.

The screening phase of the trial lasted about seven years. Women between 40 and 49 were screened every two years, and women 50 to 74 were screened roughly every three years.

"Our results indicate that in 1,000 women screened for 10 years, three breast cancer deaths would be prevented," Duffy said, adding that most of the deaths prevented would have occurred more than a decade after the screening had started.

"This indicates that the long-term benefits of screening in terms of deaths prevented are more than double those often quoted for short-term follow-up."

The new data adds to evidence on the long-term benefits of regular mammography screening.

SCREENING CONTROVERSY

New breast screening recommendations issued in 2009 by the U.S. Preventive Services Task Force, an influential advisory group, recommended against routine mammograms for women in their 40s and said women in their 50s should get mammograms every other year instead of every year.

The guidelines contradicted years of messages about the need for routine breast cancer screening starting at age 40, eliciting protests from breast cancer experts and advocacy groups who argued the recommendation for fewer screenings would confuse women and result in more deaths from breast cancer.

The changes were meant to spare women some of the worry and expense of extra tests needed to distinguish between cancer and harmless lumps. But the latest results from the Swedish study show the rate of false positive results was low.

"We saw the actual number of overdiagnosed cases was really very small -- less than 5 percent of the total," Robert Smith, director of cancer screening at the American Cancer Society and one of the study's authors, said in a telephone interview.

Many groups, including the American Cancer Society, have stuck by their long-standing recommendations of a yearly breast exam for women starting at age 40, stressing that the breast X-rays have been proven to save lives by spotting tumors early, when they are most easily treated.

"I think for anybody who was beginning to have their faith shaken in the value of mammography, these data show mammography is quite valuable as a public health approach to reducing deaths from breast cancer," Smith said.

Duffy said he thinks screening women 40 to 54 every 18 months and screening women 55 and older every two years would be a reasonable schedule.

He said the new findings do not speak to the frequency of screening issue, but they do make clear that screening works.

"Everyone must make up their own mind, but certainly from combined results from all the screening trials, mammography in women aged 40-49 does reduce deaths from breast cancer," he said.

Breast cancer is the second-leading cause of cancer death among U.S. women, after lung cancer. It kills 500,000 people globally every year and is diagnosed in close to 1.3 million people around the world.

(Editing by Todd Eastham)

View the original article here