The habitable zone around sun-like stars might be a little wider – or thinner – depending on how big you thought the habitable zone was in the first place, suggests new research in the journal Nature.

The findings, based on 3-D models of the runaway greenhouse gas effect, may alter the estimated number of habitable planets around sun-like stars in our galaxy — and they may also may affect how future planet-hunting space telescopes are designed and built.

The habitable zone is the doughnut-shaped "Goldilocks" region around a star where a planet would be warm enough to have...

Space rock, or space rocks? A new study of asteroid 4179 Toutatis suggests the large asteroid that zips past Earth every four years is actually a collection of rocky fragments held together by gravity.

"We may conclude that Toutatis is not a monolith, but most likely a coalescence of shattered fragments," the researchers wrote in a paper in Scientific Reports. 

The study, published Thursday, is based on images of the asteroid collected by the Chinese space probe Chang'e-2 (see above).

After completing its primary mission to study the moon in 2011, Chang'e-2 was positioned to take images of...

The phrase "we've found something unexpected" is the kind of broadside a patient or research subject should never have to hear for the first time after the discovery is made. That is the overriding message of a report by a presidential panel on the ethics of "incidental findings" in medical treatment, biomedical research and commercial testing aimed at health-conscious consumers.

Before performing a scan, ordering a tissue analysis or selling a customer a screening test, the physicians, researchers and companies delivering these services should have prepared patients, research subjects and...

Scientists have succeeded in greatly extending the lifespan of a simple worm through "genetic trickery" and hope to begin similar experiments on mammals, they say.

In a paper published Thursday in the journal Cell Reports, researchers at the Buck Institute for Research on Aging in Novato, Calif., said they had extended the lifespan of tiny Caenorhabditis elegans to the human equivalent of 400 or 500 years.

Normally, the 1-millimeter-long, translucent nematode lives just several weeks. However, by combining two genetic mutations that inhibit key molecules involved in insulin signaling, or IIS,...

Scientists know that the best way to make a vodka martini is to mix the ingredients with a thin wooden spoon -- it combines the ingredients effectively without raising the drink’s temperature the way a metal stirrer would. So why would James Bond, the world’s most sophisticated martini drinker, routinely order his cocktail “shaken, not stirred”?

A trio of British medical researchers believe they have the answer: The heavy-drinking 007 most likely suffered from an alcohol-induced tremor that forced him to shake his martinis. In fact, they argue, the British Secret...

Jupiter’s icy moon Europa squirts water like a squishy bath toy when it’s squeezed by the gas giant’s gravity, scientists say. Using NASA’s Hubble Space Telescope, they caught two 124-mile-tall geysers of water vapor spewing out over seven hours from near its south pole.

The discovery, described in the journal Science and at the American Geophysical Union meeting in San Francisco, shows that Europa is still geophysically active – and that this world in our own solar system could hold an environment friendly to life.

"It’s exciting," said Lorenz Roth, a...

The hole in the ozone layer is stabilizing but will take until about 2070 to fully recover, according to new research by NASA scientists.

The assessment comes more than two decades after the Montreal Protocol, the international treaty that banned chlorofluorocarbons and other compounds that deplete the ozone layer, which shields the planet from harmful ultraviolet rays.

Levels of chlorine in the atmosphere are falling as a result of the treaty, but have not yet dropped below the threshold necessary to have a shrinking effect on the ozone hole that forms each year over Antarctica, according to...

The risk that an American male will commit violence with a firearm is no easy thing to measure, says a comprehensive new report issued on the eve of the Sandy Hook Elementary School shooting's first anniversary.

If he is to become the perpetrator in one of the 109,000 gun-related deaths and injuries that occur each year in the United States, this male (and in more than 90% of cases, it is a male) is likely to have been dealt a lifelong series of toxic exposures and steady challenges, and to have gotten little help in dealing with them.

His setbacks may start in utero, with drug exposure, poor...

Up to a fifth of U.S. service members who served in Iraq and Afghanistan have come home with a blast-related concussion or post-traumatic stress disorder — or both.

A study published Wednesday in the journal JAMA Psychiatry helps detail the relationship between the two conditions.

Marines who suffered mild traumatic brain injuries while deployed were roughly twice as likely to get PTSD, researchers found.

One likely explanation is that the bomb blasts, the most common cause of brain injuries during the wars, are psychologically traumatizing as well.

In addition, structural changes in the...

What does it matter if you were cute in high school? More than you might think.

A new study undertaken by researchers from the University of Illinois at Chicago and the University of Texas at Austin finds that teens rated as good-looking in high school got higher grades and were ultimately more likely to graduate college and get bigger paychecks as adults.

Well into adulthood, “people’s personal appearance has powerful effects on their life chances,” sociologists Rachel A. Gordon and Robert Crosnoe wrote in a briefing paperprepared for the Council on Contemporary Families....

The video above, taken by NASA's Juno spacecraft as it zipped past Earth on Oct. 9, may be imperfect, but it will give you chills.

Captured with sensors designed to track faint stars rather than rocky planets, the video begins just as the Earth-and-moon system has come into Juno's view, 600,000 miles in the distance. 

As Juno flies in closer, you can see the small white dot of the moon gliding silently around a fuzzy blue Earth. Closer still, and the moon moves off into the margins as our spinning planet takes up more of the field of view.

PHOTOS: Moons of the solar system

"If Captain Kirk of...