Mobile phone cancer link unclear, study

The largest study to date on the safety of mobile phones has found no clear link to brain cancer, but researchers say further research is needed given the increasingly intensive use of the technology.

The study, by the World Health Organization's International Agency for Research on Cancer (IARC), appears this week in International Journal of Epidemiology.

"The results really don't allow us to conclude that there is any risk associated with mobile phone use, but... it is also premature to say that there is no risk associated with it," says IARC's director Dr Christopher Wild.

The study looked at almost 13,000 mobile phone users, including 2,708 people with glioma tumours and 2,409 people with meningioma tumours in 13 countries.

It found no increased risk of glioma or meningioma tumours after 10 years of using a mobile phone, although it found "suggestions of higher risk" for the heaviest users.

The heaviest users who reported using their phones on the same side of their heads had a 40% higher risk for gliomas and 15% for meningiomas, but the researchers said "biases and errors" prevent making a causal link.

Given that the heaviest users in the study talked an average of half an hour per day on their mobile phones, a figure which is not heavy by today's standards, the researchers recommend further research.

The research, involved 21 scientists from the Interphone International Study Group, which received 19.2 million euros (A$27 million) in funding, around 5.5 million euros (A$7.7) of which came from industry sources.

Water Discovered on an Asteroid—A First

Water has been spotted on an orbiting asteroid for the first time, according to a new study of a space rock that appears to be coated with frost.

What's more, the frost seems to be mixed with carbon-bearing material, according to results from two independent teams studying the asteroid, which is known as 24 Themis.

"We report the first detection of water ice and of organic molecules on an asteroid, and they are both on the same asteroid," said Humberto Campins of the University of Central Florida, leader of one of the teams.

Both teams used NASA's Infrared Telescope Facility in Hawaii to watch how sunlight reflected off the asteroid at different wavelengths, revealing the watery signature.

A closer look at similar asteroids, perhaps during a proposed NASA mission, could help reveal whether the water we drink—and maybe even the building blocks of life—were delivered to Earth by impacting space rocks. (See "Comet Swarm Delivered Earth's Oceans?")

Asteroid Water Ice Exposed by "Impact Gardening"?

Asteroids are believed to be the leftovers of planet formation, with compositions that have remained almost pristine for 4.6 billion years.

The asteroid 24 Themis orbits about x million miles (480 million kilometers) from the sun. It's one of the largest asteroids in the main asteroid belt, which lies between the orbits of Mars and Jupiter. (Explore an interactive solar system).

Unlike comets, which originate from beyond the orbit of Neptune, asteroids are thought to be relatively dry, since they orbit much closer to the sun.

But previous theories have suggested that ice could still exist in the main asteroid belt if it's buried below the surfaces of the space rocks. (See asteroid and comet pictures.)

In fact, two nearby "relatives" of 24 Themis are members of a strange group called main-belt comets, which are known to leave dust tails that may be fueled by water ice sublimating, or turning directly from a solid into a gas. (Related: "Strange 'Comet' May Be Asteroid Collision Debris.")

The discovery of frost on 24 Themis means that the asteroid "represents a 'living' window into the early solar system in the form of ice that, according to conventional wisdom, should have been long gone," astrophysicist Henry Hsieh, of Queen's University Belfast, wrote in a commentary on the new study.

On 24 Themis, the frost might be coming from subsurface ice that sublimates when sunlight warms up the asteroid, sending vapor to the surface. The gas then recondenses on the surface when darkness falls and temperatures dip, study author Campins said.

Or micrometeorites may practice "impact gardening," churning the surface enough to gradually uncover a layer of preserved subsurface ice.

Or the answer may be something else entirely, Campins admits: "One of the fun things about having so little information is how much one can speculate," he said.

Hubble Telescope Catches Superfast Runaway Star

A stellar speed demon racing away from its home may be a never before seen type of runaway star, astronomers have announced.

Dubbed 30 Dor 016, the massive star is whipping through space at a record-breaking 250,000 miles (400,000 kilometers) an hour. The fugitive already appears to have traveled 375 light-years from its birthplace: a star cluster called R136 deep in the Tarantula Nebula.

(Related: "Mystery Space Object May Be Ejected Black Hole.")

Astronomers caught the stellar runaway in Hubble Space Telescope data taken shortly after the last space shuttle servicing mission in May 2009. (See pictures taken by the upgraded Hubble.)

The team chose the star as a target to help calibrate the newly installed Cosmic Origins Spectrograph (COS), an instrument designed to look at the light signatures—or spectra—of very distant, faint objects.

After looking at the light coming from 30 Dor 016, the scientists "knew immediately that it was a massive star that had stellar winds blowing at breakneck speeds," said study co-author Danny Lennon, an astronomer at the Space Telescope Science Institute in Baltimore, Maryland.

"Given that the mass of the star is proportional to the velocity of the material being expelled, we knew right away that its wind was the fastest ever seen."

Such powerful wind means that the star is incredibly massive: Lennon and colleagues calculate that the runaway is roughly 90 times the mass of our sun.

Mystery Space Object May Be Ejected Black Hole

Then again, the strange body could be a rare type of supernova or an oddball "midsize" black hole—more massive than black holes born when single stars explode but "lighter" than the supermassive ones at the centers of galaxies.

"All three of those [options] are exotic and have something peculiar to them," said study co-author Peter Jonker, an astronomer with the Netherlands Institute for Space Research in Utrecht.

Off-center Black Holes Wanted

Jonker and his colleagues found the mystery object while on the hunt for off-center supermassive black holes that are thought to form when two galaxies merge. (Related: "Colossal Four-Galaxy Collision Discovered.")

Most, if not all, galaxies are thought to have supermassive black holes at their cores. Recent computer simulations suggest that when two galaxies merge, so do their central black holes.

But the newly formed black hole combo "actually receives a kick" from gravitational forces generated by the galactic merger, Jonker said. The kick, according to the models, "launches this newly formed black hole out of the center of the galaxy." (See "Hundreds of 'Rogue' Black Holes May Roam Milky Way.")

Sorting through archived data from the Chandra X-ray Observatory, the team found an interesting candidate in a galaxy half a billion light years away from Earth. The extremely bright x-ray object is about ten thousand light-years from its galactic center.

Based on the Chandra data, however, the astronomers couldn't rule out the possibility that the newfound object actually lies behind the galaxy in question.

So the team compared their x-ray information with archived optical data from the Hubble Space Telescope. They found that the mystery object emits a bright blue light in visible wavelengths. (See NASA astronomer's picks for the top Hubble pictures of the past 20 years.)

Hole in Space Found by Orbiting Telescope

The hole lies in a nebula called NGC 1999, a bright cloud of dust and gas in the constellation Orion. The nebula glows with light from a nearby star.

The Hubble Space Telescope first snapped a picture of the nebula in December 1999. Astronomers assumed that an inky spot in the cloud was a blob of cooler gas and dust that's so dense it blocks visible light from passing through. (See a Hubble picture that shows dark globs in another nebula.)

But new pictures from the European Space Agency's Herschel Space Observatory show that the blob really is an empty void. That's because Herschel sees in infrared, which should allow the telescope to peer through dense dust and see any objects inside.

Even to Herschel, however, the blob looked black.

Astronomers think that the 0.2-light-year-wide hole was made by the fitful birthing process of a nearby stellar embryo called V380 Ori. (Related: "Big Bang Ripples Formed Universe's First Stars.")

The protostar is already 3.5 times the mass of our sun. The team thinks the newborn is signaling its near maturity by shooting out superfast columns of gas from its poles that are blasting away any leftover material from the star's formation.

"We think the star is launching a bipolar jet at hundreds of kilometers per second that is punching a gigantic hole in the surrounding cloud," said team leader Tom Megeath of the University of Toledo in Ohio. "Essentially these bolts of gas are being shot forward and are sweeping away all the gas and dust."

Herschel, the Astronomer, Also Saw Space Holes

Megeath added that the telescope that found the hole is named after 19th-century astronomer William Herschel. In his calalogs of the night sky, Herschel recorded several black patches that he thought were holes but which turned out to be dark clouds.

Ball Lightning May Be All in Your Head

For hundreds of years eyewitnesses have reported brief encounters with the golf ball- to tennis ball-size orbs of electricity. But scientists have been unable to agree on how and why ball lightning forms, since the phenomenon is rare and very short-lived. (See "Ball Lightning: A Shocking Scientific Mystery.")

Ball lightning is often reported during thunderstorms, and it's known that multiple consecutive lightning strikes can create strong magnetic fields. So Joseph Peer and Alexander Kendl at the University of Innsbruck in Austria wondered whether ball lightning is really a hallucination induced by magnetic stimulation of the brain's visual cortex or the eye's retina.

In previous experiments, other scientists had exposed humans to strong, rapidly changing magnetic fields using a medical machine called a transcranial magnetic stimulator, or TMS. The machine's magnetic fields are powerful enough to induce electric currents in human brain cells without being harmful.

Focusing magnetic fields on the visual cortex of the brain caused the subjects to see luminous discs and lines. When the focus was moved around within the visual cortex, the subjects reported seeing the lights move.

In their paper, which appeared online May 7 on the physics research website, Peer and Kendl argue that magnetic fields made by lightning could have the same effect as TMS machines on nearby humans.

In fact, the pair thinks about half of all ball lightning reports are actually tricks of the mind induced by magnetism.

Jupiter Loses Big Belt

Two wide stripes—known as the equatorial belts—normally circle the huge planet, products of the fast-moving jet streams that roar through Jupiter's atmosphere.

But pictures of Jupiter taken by an amateur astronomer show that sometime during the past couple weeks, the south equatorial belt completely faded from view.

"The basic view of Jupiter is of two dark belts. Now there is only one," said Alan MacRobert, senior editor of Sky & Telescope magazine.

"This is the most obvious change on Jupiter that I can recall," he said, adding that anyone with a backyard telescope should be able to see the difference. "Any instrument powerful enough to show any of Jupiter's surface features will easily reveal the change."

However, the planet's "belt buckle" remains: The lost stripe "means that Jupiter's Great Red Spot is now floating all alone in whiteness, whereas usually it is in an indentation in the south equatorial belt," MacRobert said.

The spot—actually a raging storm three times bigger than Earth—is rarely brick red, he added, and often becomes quite pale. MacRobert characterizes its current color as "somewhat orangy." (Find out why the Great Red Spot has been shrinking.)

Jupiter's Dark Belt Lost to Light Cloud Cover?

Despite the dramatic change on Jupiter, the lost belt doesn't concern experts. The planet has lost this stripe before, most recently in the 1970s and the early '90s. So far, the stripe has always reappeared.

Astronomers are, however, somewhat stumped for a complete explanation.

A dozen or so jet streams move alternately east-west and west-east on Jupiter, said planetary scientist Andrew Ingersoll of the California Institute of Technology. The clouds in between these jet streams create the planet's multicolored stripes and swirls.