But there is evidence of a warmer and wetter past – features resembling dry riverbeds and minerals that form in the presence of water indicate water once flowed through Martian sands. Since liquid water is required for all known forms of life, scientists wonder if life could have risen on Mars, and if it did, what became of it as the Martian climate changed.

New research reveals there is hope for Mars yet. The first definitive detection of methane in the atmosphere of Mars indicates the planet is still alive, in either a biologic or geologic sense, according to a team of NASA and university scientists.

“Methane is quickly destroyed in the Martian atmosphere in a variety of ways, so our discovery of substantial plumes of methane in the northern hemisphere of Mars in 2003 indicates some ongoing process is releasing the gas,” said Dr. Michael Mumma of NASA’s Goddard Space Flight Center in Greenbelt, Md.

“At northern mid-summer, methane is released at a rate comparable to that of the massive hydrocarbon seep at Coal Oil Point in Santa Barbara, Calif.”

Methane – four atoms of hydrogen bound to a carbon atom – is the main component of natural gas on Earth. It’s of interest to astrobiologists because organisms release much of Earth’s methane as they digest nutrients. However, other purely geological processes, like oxidation of iron, also release methane.

“Right now, we don’t have enough information to tell if biology or geology – or both – is producing the methane on Mars,” said Mumma.

“But it does tell us that the planet is still alive, at least in a geologic sense. It’s as if Mars is challenging us, saying, hey, find out what this means.” Mumma is lead author of a paper on this research appearing in Science Express Jan. 15.

If microscopic Martian life is producing the methane, it likely resides far below the surface, where it’s still warm enough for liquid water to exist. Liquid water, as well as energy sources and a supply of carbon, are necessary for all known forms of life.

“On Earth, microorganisms thrive 2 to 3 kilometers (about 1.2 to 1.9 miles) beneath the Witwatersrand basin of South Africa, where natural radioactivity splits water molecules into molecular hydrogen (H2) and oxygen.

The organisms use the hydrogen for energy. It might be possible for similar organisms to survive for billions of years below the permafrost layer on Mars, where water is liquid, radiation supplies energy, and carbon dioxide provides carbon,” said Mumma.

“Gases, like methane, accumulated in such underground zones might be released into the atmosphere if pores or fissures open during the warm seasons, connecting the deep zones to the atmosphere at crater walls or canyons,” said Mumma.

“Microbes that produced methane from hydrogen and carbon dioxide were one of the earliest forms of life on Earth,” noted Dr. Carl Pilcher, Director of the NASA Astrobiology Institute which partially supported the research.

“If life ever existed on Mars, it’s reasonable to think that its metabolism might have involved making methane from Martian atmospheric carbon dioxide.”

However, it is possible a geologic process produced the Martian methane, either now or eons ago. On Earth, the conversion of iron oxide (rust) into the serpentine group of minerals creates methane, and on Mars this process could proceed using water, carbon dioxide, and the planet’s internal heat. Although we don’t have evidence on Mars of active volcanoes today, ancient methane trapped in ice “cages” called clathrates might now be released.

The team found methane in the atmosphere of Mars by carefully observing the planet over several Mars years (and all Martian seasons) with NASA’s Infrared Telescope Facility, run by the University of Hawaii, and the W. M. Keck telescope, both at Mauna Kea, Hawaii.

The team used spectrometer instruments attached to the telescopes to make the detection. Spectrometers spread light into its component colors, like a prism separates white light into a rainbow.

The team looked for dark areas in specific places along the rainbow (light spectrum) where methane was absorbing sunlight reflected from the Martian surface.

They found three such areas, called absorption lines, which together are a definitive signature of methane, according to the team.

They were able to distinguish lines from Martian methane from the methane in Earth’s atmosphere because the motion of the Red Planet shifted the position of the Martian lines, much as a speeding ambulance causes its siren to change pitch as it passes by.

“We observed and mapped multiple plumes of methane on Mars, one of which released about 19,000 metric tons of methane,” said Dr. Geronimo Villanueva of the Catholic University of America, Washington, D.C. Villanueva is stationed at NASA Goddard and is co-author of the paper.

“The plumes were emitted during the warmer seasons – spring and summer – perhaps because the permafrost blocking cracks and fissures vaporized, allowing methane to seep into the Martian air. Curiously, some plumes had water vapor while others did not,” said Villanueva.

According to the team, the plumes were seen over areas that show evidence of ancient ground ice or flowing water. For example, plumes appeared over northern hemisphere regions such as east of Arabia Terra, the Nili Fossae region, and the south-east quadrant of Syrtis Major, an ancient volcano 1,200 kilometers (about 745 miles) across.

It will take future missions, like NASA’s Mars Science Laboratory, to discover the origin of the Martian methane. One way to tell if life is the source of the gas is by measuring isotope ratios. Isotopes are heavier versions of an element; for example, deuterium is a heavier version of hydrogen. In molecules that contain hydrogen, like water and methane, the rare deuterium occasionally replaces a hydrogen atom.

Since life prefers to use the lighter isotopes, if the methane has less deuterium than the water released with it on Mars, it’s a sign that life is producing the methane. The research was funded by NASA’s Planetary Astronomy Program and the NASA Astrobiology Institute.

Dr Andy Ridgwell and colleagues at the University of Bristol argue that we should select crop varieties in order to exert a control on the climate, in the same way that we currently cultivate specific varieties to maximize and fine-tune food production.

Dr Ridgwell said: “We have evaluated the effect of our approach in a global climate model. By choosing from among current crop varieties, our best estimate for how much reflectivity might be increased leads us to predict that summer-time temperatures could be reduced by more than 1°C throughout much of central North America and mid-latitude Eurasia. Ultimately, further regional cooling of the climate could be made through selective breeding or genetic modification to optimise crop plant albedo.”

The team emphasised that unlike growing biofuels, such a plan could be achieved without disrupting food production, either in terms of yield or the types of crops grown. “We propose choosing between different varieties of the same crop species in order to maximize solar reflectivity rather than changing crop type, although the latter could also produce climatic benefits,” explained Ridgwell.

Over the next hundred years, making these kinds of decisions would be equivalent to averting the carbon footprint of 195 billion tonnes of CO2 emitted into the atmosphere. Farmers could be encouraged to grow such crops by issuing them with carbon credits. Ridgwell has calculated that if such a mechanism were in place farmers might expect to earn in the region of 23 euros per hectare per year for the warming averted. Biofuels currently earn 45 euros per hectare per year, but take up valuable agricultural land needed for growing crops.

Plants differ in their albedo because of differences in the properties of the leaf’s surface and how the leaves are arranged (called ‘canopy morphology’). The team therefore propose that the varieties grown should be chosen for their reflective properties alongside other considerations already made when planting crops, such as the food processing characteristics of a grain.

Since society has so far remained unwilling to make the drastic reductions in fossil fuel use needed to cut carbon dioxide emissions, simple alternatives such as growing more reflective crops are a realistic way of helping reduce the severity of heat waves and droughts in these regions. Results could be achieved very quickly and at very little cost.

“There is a clear need for more research into characterising the variability in albedo that currently exists between the different variants and strains of common crop plants,” commented Ridgwell. “We are applying for funding that will enable us to better quantify what is possible now, what variability there is for future selective breeding, and whether there is a need for genetic modification in the future”.

A new comprehensive scientific synthesis of past Arctic climates demonstrates for the first time the pervasive nature of Arctic climate amplification.

The U.S. Geological Survey led this new assessment, which is a synthesis of published science literature and authored by a team of climate scientists from academia and government. The U.S. Climate Change Science Program commissioned the report, which has contributions from 37 scientists from the United States, Germany, Canada, the United Kingdom and Denmark.

The new report also makes several conclusions about the Arctic:

* Taken together, the size and speed of the summer sea-ice loss over the last few decades is highly unusual compared to events from previous thousands of years, especially considering that changes in Earth’s orbit over this time have made sea-ice melting less, not more, likely.
* Sustained warming of at least a few degrees (more than approximately 4° to 13°F above average 20th century values) is likely to be sufficient to cause the nearly complete, eventual disappearance of the Greenland ice sheet, which would raise sea level by several meters.
* The current rate of human-influenced Arctic warming is comparable to peak natural rates documented by reconstructions of past climates. However, some projections of future human-induced change exceed documented natural variability.
* The past tells us that when thresholds in the climate system are crossed, climate change can be very large and very fast. We cannot rule out that human induced climate change will trigger such events in the future.

“By integrating research on the past 65 million years of climate change in the entire circum-Arctic, we have a better understanding on how climate change affects the Arctic and how those effects may impact the whole globe,” said USGS Director Mark Myers. “This report provides the first comprehensive analysis of the real data we have on past climate conditions in the Arctic, with measurements from ice cores, sediments and other Earth materials that record temperature and other conditions.”

“Obviously, the sun is Earth’s life blood,” said Richard Fisher, director of the Heliophysics division at NASA Headquarters in Washington. “To mitigate possible public safety issues, it is vital that we better understand extreme space weather events caused by the sun’s activity.”

Besides emitting a continuous stream of plasma called the solar wind, the sun periodically releases billions of tons of matter called coronal mass ejections. These immense clouds of material, when directed toward Earth, can cause large magnetic storms in the magnetosphere and upper atmosphere. Such space weather can affect the performance and reliability of space-borne and ground-based technological systems.

Space weather can produce solar storm electromagnetic fields that induce extreme currents in wires, disrupting power lines, causing wide-spread blackouts and affecting communication cables that support the Internet. Severe space weather also produces solar energetic particles and the dislocation of the Earth’s radiation belts, which can damage satellites used for commercial communications, global positioning and weather forecasting. Space weather has been recognized as causing problems with new technology since the invention of the telegraph in the 19th century.

A catastrophic failure of commercial and government infrastructure in space and on the ground can be mitigated through raising public awareness, improving vulnerable infrastructure and developing advanced forecasting capabilities. Without preventive actions or plans, the trend of increased dependency on modern space-weather sensitive assets could make society more vulnerable in the future.

NASA requested the study to assess the potential damage from significant space weather during the next 20 years. National and international experts from industry, government and academia participated in the study. The report documents the possibility of a space weather event that has societal effects and causes damage similar to natural disasters on Earth.

“From a public policy perspective, it is quite significant that we have begun the extremely challenging task of assessing space weather impacts in a quantitative way,” said Daniel Baker, professor and director of the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. Baker chaired the panel that prepared the report.

“Whether it is terrestrial catastrophes or extreme space weather incidents, the results can be devastating to modern societies that depend in a myriad of ways on advanced technological systems,” said Baker. “We were delighted that NASA helped support bringing together dozens of world experts from industry and government to share their experiences and begin planning of improved public policy strategies.”

The sun is currently near the minimum of its 11-year activity cycle. It is expected that solar storms will increase in frequency and intensity toward the next solar maximum, expected to occur around 2012.

The Heliophysics Division of NASA’s Science Mission Directorate in Washington provided funding for the study. The division seeks to understand the sun, its solar processes and the interaction of solar plasma and radiation with Earth, other planets and the universe. Understanding the connections between the sun and its planets will allow better prediction on the impacts of solar activity on humans, technological systems and even the presence of life itself in the universe.

The National Academies are chartered by Congress to provide independent technical and scientific advice to the federal government.

The eclipse was due to begin in Canada at 0804 GMT, track across Greenland and eastern Russia and end around sunset on Friday to the east of Xi’an, China‘s ancient imperial capital.

Eclipses were dangerous omens for ancient Chinese astronomers, but this one comes exactly a week before the torch is lit in Beijing for the opening ceremony of Games designed to restore China’s pride and showcase its achievements.

Planeloads of cheerful foreign eclipse chasers converged on Jiayuguan, in Gansu Province, and in the hot deserts of Xinjiang, to watch the sky go dark and a halo wreathe the hidden sun.

“I’ve come all the way from California for this. It’s going to be my 11th eclipse, I try to see them all,” said Dave Balch, a cancer care advisor wearing an eclipse T-shirt.

Scientists studying the sun’s surface prepared for a brief glimpse of the faint outer corona that is normally obscured by the sun’s brightness.

“Nowadays, the equipment works well enough that we do have time to look up at the eclipse,” said Jay Pasachoff, a professor at Williams College who traveled to Novosibirsk, Russia for his 47th eclipse.

“It’s very dramatic and awe-inspiring when the darkness suddenly comes. That’s why thousands of tourists go to see.”

Hundreds of millions of people won’t have to go any further than their front doors on July 22, 2009, when the next solar eclipse will cross India and northern Bangladesh, then run along the Yangtze River from Chongqing to Shanghai in the most populated path ever.

OMEN

Chinese hope that the Olympics will usher in a new era where China is once more as modern, wealthy and important as it was more than 10 centuries ago, when imperial astronomers were among the world’s best scientists and camel caravans carried riches along the pass guarded by Jiayuguan.

Chinese astronomers in the state of Lu, present day Shandong, carefully recorded solar eclipses that can be dated as far back as 720 BC. Earlier than that, inscriptions on oracle bones asked what eclipses might portend.

Eclipses were sometimes linked to the subsequent deaths of emperors and empresses, said F. Richard Stephenson, professor emeritus at Durham University in northern England.

Chinese astronomers understood what caused eclipses and could predict them very accurately by AD 300, but superstitious courtiers and peasants still banged drums to scare away the dragon they thought was eating the sun.

People still find their lives can be touched by eclipses, but the modern view is a little more philosophic.

“I was born during an eclipse, and I have always felt that’s made my life more fortunate,” said a driver named Zhou. “But I didn’t turn out to have any special genius, so I can’t say the eclipse left any mark of fate or destiny on me.”

source: http://news.yahoo.com/s/nm/20080801/sc_nm/eclipse_dc;_ylt=AuvYTvTtjfxb7Srhpx39VHWHgsgF

The Body/Mind Connection

Medical science is only beginning to understand the ways in which the mind influences the body. The placebo effect, for example, demonstrates that people can at times cause a relief in medical symptoms or suffering by believing the cures to be effective – whether they actually are or not. Using processes only poorly understood, the body’s ability to heal itself is far more amazing than anything modern medicine could create.

Psychic powers and ESP

Psychic powers and extra-sensory perception (ESP) rank among the top ten unexplained phenomena if for no other reason than that belief in them is so widespread. Many people believe that intuition (see #3) is a form of psychic power, a way of accessing arcane or special knowledge about the world or the future. Researchers have tested people who claim to have psychic powers, though the results under controlled scientific conditions have so far been negative or ambiguous. Some have argued that psychic powers cannot be tested, or for some reason diminish in the presence of skeptics or scientists. If this is true, science will never be able to prove or disprove the existence of psychic powers.

Near-Death Experiences and Life After Death

People who were once near death have sometimes reported various mystical experiences (such as going into a tunnel and emerging in a light, being reunited with loved ones, a sense of peace, etc.) that may suggest an existence beyond the grave. While such experiences are profound, no one has returned with proof or verifiable information from “beyond the grave.” Skeptics suggest that the experiences are explainable as natural and predictable hallucinations of a traumatized brain, yet there is no way to know with certainty what causes near-death experiences, or if they truly are visions of “the other side.”

There is no doubt that UFOs (Unidentified Flying Objects) exist – many people see things in the skies that they cannot identify, ranging from aircraft to meteors. Whether or not any of those objects and lights are alien spacecraft is another matter entirely; given the fantastic distances and effort involved in just getting to Earth from across the universe, such a scenario seems unlikely. Still, while careful investigation has revealed known causes for most sighting reports, some UFO incidents will always remain unexplained

Deja vu

Deja vu is a French phrase meaning ‘already seen,’ referring to the distinct, puzzling, and mysterious feeling of having experienced a specific set of circumstances before. A woman might walk into a building, for example, in a foreign country she’d never visited, and sense that the setting is eerily and intimately familiar. Some attribute deja vu to psychic experiences or unbidden glimpses of previous lives. As with intuition (see #3), research into ,human psychology can offer more naturalistic explanations, but ultimately the cause and nature of the phenomenon itself remains a mystery.

Ghosts

From the Shakespeare play “MacBeth” to the NBC show “Medium,” spirits of the dead have long made an appearance in our culture and folklore. Many people have reported seeing apparitions of both shadowy strangers and departed loved ones. Though definitive proof for the existence of ghosts remains elusive, sincere eyewitnesses continue to report seeing, photographing, and even communicating with ghosts. Ghost investigators hope to one day prove that the dead can contact the living, providing a final answer to the mystery.

Mysterious Disappearances

People disappear for various reasons. Most are runaways, some succumb to accident, a few are abducted or killed, but most are eventually found. Not so with the truly mysterious disappearances. From the crew of the Marie Celeste to Jimmy Hoffa, Amelia Earhart, and Natalee Holloway, some people seem to have vanished without a trace. When missing persons are found, it is always through police work, confession, or accident never by ‘psychic detectives’). But when the evidence is lacking and leads are lost, even police and forensic science can’t always solve the crime.

Intuition

Whether we call it gut feelings, a ‘sixth sense,’ or something else, we have all experienced intuition at one time or another. Of course, gut feelings are often wrong (how many times during aircraft turbulence have you been sure your plane was going down?), but they do seem to be right much of the time. Psychologists note that people subconsciously pick up information about the world around us, leading us to seemingly sense or know information without knowing exactly how or why we know it. But cases of intuition are difficult to prove or study, and psychology may only be part of the answer.

Bigfoot

For decades, large, hairy, manlike beasts called Bigfoot have occasionally been reported by eyewitnesses across America. Despite the thousands of Bigfoot that must exist for a breeding population, not a single body has been found. Not one has been killed by a hunter, struck dead by a speeding car, or even died of natural causes. In the absence of hard evidence like teeth or bones, support comes down to eyewitness sightings and ambiguous photos and films. Since it is logically impossible to prove a universal negative, science will never be able to prove that creatures like Bigfoot and the Loch Ness monster do not exist, and it is possible that these mysterious beasts lurk far from prying eyes.

The Taos Hum

Some residents and visitors in the small city of Taos, New Mexico, have for years been annoyed and puzzled by a mysterious and faint low-frequency hum in the desert air. Oddly, only about 2 percent of Taos residents report hearing the sound. Some believe it is caused by unusual acoustics; others suspect mass hysteria or some secret, sinister purpose. Whether described as a whir, hum, or buzz and whether psychological, natural, or supernatural no one has yet been able to locate the sound’s origin.

The star-shaped bacterium was isolated from mine-slime, 1.7 km below the surface. The ruler shown for scale is in centimetres.

The cell membrane of the bacterium twists and turns to provide its unique shape.

Researchers studying life in the deep subsurface of our planet have discovered a unique bacterium living 1 mile (1.7 km) below the Earth’s surface. The tiny bacteria live in a community of subsurface microbes inhabiting a South African platinum mine.

The deep subsurface of Earth harbors many unique microbes that are only accessible through large scale drilling projects or mining. By trekking into the ultra-deep mines of South Africa, researchers are getting a rare glimpse into this unique habitat. In the depths of South Africa’s Northam Platinum mine, scientists from the University of Western Ontario and Princeton University have gained access to many previously undiscovered microbial communities.

While mining and drilling allow scientists to sample the unique environment below the Earth’s soil, these activities obviously disturb the subsurface of the planet. Digging into the ground disrupts the microbial communities that live there. When people enter mines and caves, they bring with them a massive number of non-native microbes. Because of this, it’s difficult to get uncontaminated samples.

The team from the recent study decided to test samples from mines in order to determine just how contaminated they really are. They collected samples from slime, or biofilm, growing on the walls of the Northam mine in South Africa. An explosion of life occurs where subsurface water leaks out of the mine walls and meets with oxygen, leading to films of microscopic organisms.

Previously, researchers overlooked these biofilms because they thought the films would be too heavily contaminated. To test this theory, the team determined whether or not their biofilms were formed by contaminant organisms from the surface, or by unique subsurface organisms.

The study, by Greg Wanger, Tullis Onstott and Gordon Southam, was published in a recent edition of the journal Geobiology.

The authors showed that the biofilms contained a number of unique organisms associated with the deep subsurface, and therefore such films might be an excellent place to search for new and unusual species of microbes. In fact, in their study the team came across one particularly strange microbe shaped like a tiny, microscopic star.

Shaping up bacteria

Microbes come in a number of shapes and sizes, but most of these shapes are rather uncomplicated. The easiest shape for a microbe to make is a sphere. Like a soap bubble, the cell membranes of microbes tend to naturally form this simple structure due to forces such as surface tension.

According to the research team, “the diversity of all bacterial shapes is more difficult to explain.” Other shapes often seen in microbes include rods and spirals, but these take a bit of extra work on the part of the microbe. To make more complicated shapes, microbes have to use extra energy to fight against the natural forces that favor the sphere. According to the research team, the biofilms from Northam mine “contained a morphologically diverse assortment of bacteria.”

Some rare microbes go beyond the common and form radically unique shapes. The microbe discovered in the depths of the Northam mine is one such microbe. Using high-powered microscopes, the team captured images that show star-shaped cells with four to nine points. It’s a unique structure for a microbe and one that has not been witnessed before.

So why would a microbe want to take the shape of a star?

As living organisms, every microbe needs food. When we need food, we can simply pick it up and put it in our mouths. That’s not the case for most microbes. Many microbes simply float about in their environment in the hope that they’ll be able to absorb the nutrients they need to survive

Many microbes “eat” by letting nutrients diffuse through their cell membrane. A sphere may be easy to form, but it doesn’t provide the largest surface area for a cell. By forming a more complicated shape, with a cell wall that folds and bends, the surface area of the cell is increased in relation to its interior volume. This means there’s more cell wall through with the microbe can absorb its food.

The new microbe discovered by the researchers in South Africa has likely developed its unique shape in response to its unique environment. The deep subsurface of the planet is thought to be quite “nutrient poor” — there’s not a lot of food to go around. Microbes need to develop clever strategies to out-compete their neighbors. The surface-area-to-volume ratio for the star-shaped cells is thought to be as much as ten times better than common bacteria like e. coli. This advantage may help the stars survive amidst a neighborhood of microbes competing for the same food.

Inside planets

Scientists are just beginning to understand the unique types of life beneath the surface of our planet. Astrobiologists are particularly interested in the subsurface because it can help them understand how microbes might survive deep beneath the topsoil of other planets.

Upcoming and current missions to search for signs of past or present life on Mars are focusing on life beneath the martian soil. Right now, NASA’s Phoenix Lander is using a scoop to dig on Mars. Recent images returned from Phoenix are already revealing clues about subsurface ice on the red planet.

The European Space Agency’s ExoMars rover may take the exploration of Mars’ subsurface one step further. Current plans are to place a drill on ExoMars that could allow the rover to dig up to 12 feet.

NASA has also been developing prototype drills for use by human explorers on Mars. Drilling technologies have already been tested by NASA researchers in extreme environments on Earth, including the Canadian high arctic.

Microbes use many methods to survive in the nutrient-poor, oxygen-free, pitch-black world deep beneath our feet. Studying these microbes might provide clues about how organisms could live in harsh environments on other planets like Mars. Because of this, unique microbes like the “stars” of Northam mine may shed a bit of light on the future of planetary exploration.

Astronomers have determined how far away from its hot stellar neighbors a star must be if a swirling disk of dust around it is to stand a chance of forming planets.

Using NASA’s Spitzer Space Telescope, scientists created the first maps of so-called planetary “danger-zones,” areas where winds and radiation from super-hot stars can strip younger, cooler stars like our Sun of their planet-forming materials.

The findings suggest that so long as cool stars lie beyond about 1.6 light years, or nearly 10 trillion miles, of any hot stars, they can form planets.

“Stars move around all the time, so if one wanders into the danger zone and stays for too long, it will probably never be able to form planets,” said study leader Zoltan Balog of the University of Arizona.

The study, to be detailed in the May 20 issue of Astrophysical Journal, will help astronomers pinpoint the types of cosmic environments conducive for planet formation.

Planets are created in flat disks of gas and dust, called protoplanetary disks, which swirl around young, cool stars. According to standard planet-formation theory, over millions of years the particles clump together and grow in size like dust bunnies.

Previous studies found that the fragile protoplanetary disks can be destroyed by radiation from the most massive, hottest stars in the universe, called O-stars, in a process called photoevaporation. Ultraviolet radiation from an O-star heats and evaporates the dust and gas in the disk, while stellar winds blow the material away.

A stellar danger-zone

The team used Spitzer to search for disks around 1,000 stars in the Rosette Nebula, a turbulent star-forming region located 5,200 light-years away. The stars range from one-tenth to five times the mass of the Sun and are between 2 to 3 million years old. All are located close to at least one O-star.

The scientists found that the closer the cool stars were to their O-stars, the less likely they were to have disks. Beyond 1.6 light-years of an O-star, about 45 percent of the stars had disks, while only 27 percent of those located within the danger zone of an O-star had disks.

“The edges of the danger zone are sharply defined,” Balog said. “It is relatively safe for protoplanetary disks outside it, whereas a disk that gets dragged along by its star to be really close to an O-star could disappear in as fast as a hundred thousand years.”

That could put the brakes on just-developing planets. However, if a planet were already fully-formed when its star drifted into the danger zone of an O-star, it could potentially survive, astronomers say.

The new findings also have implications for planet formation around O-stars themselves, said study team member George Rieke, also of the University of Arizona.

“They would have to form pretty quickly,” Rieke told SPACE.com. “It doesn’t rule out the possibility completely. There are planets around pulsars, for example, but they must have formed by some rather different mechanisms.”

Pulsars are spinning stellar corpses that also emit large amounts of radiation.

The sound is awful, a new recording from space reveals.

Scientists have known about the radiation since the 1970s. It is created high above the planet, where charged particles from the solar wind collide with Earth’s magnetic field. It is related to the phenomenon that generates the colorful aurora, or Northern Lights.

The radio waves are blocked by the ionosphere, a charged layer atop our atmosphere, so they do not reach Earth. That’s good, because the out-of-this-world radio waves are 10,000 times stronger than even the strongest military signal, the researchers said, and they would overwhelm all radio stations on the planet.

Theorists had long figured the radio waves, which were not well studied, oozed into space in an ever-widening cone, like light from a torch.

But new data from the European Space Agency’s Cluster mission, a group of four high-flying satellites, reveals the bursts of radio waves head off to the cosmos in beam-like fashion, instead.

This means they’re more detectable to anyone who might be listening.

The Auroral Kilometric Radiation (AKR), as it is called, is beamed out in a narrow plane, as if someone had put a mask over a torch and left a slit for the radiation to escape.

This flat beam could be detected by aliens who’ve figured this process out, the researchers say. The knowledge could also be used by Earth’s astronomers to detect planets around other stars, if they can build a new radio telescope big enough for the search. They could also learn more about Jupiter and Saturn by studying AKR, which should emit from the auroral activity on those worlds, too.

“Whenever you have aurora, you get AKR,” said Robert Mutel, a University of Iowa researcher involved in the work.

The AKR bursts — Mutel and colleagues studied 12,000 of them – originate in spots the size of a large city a few thousand miles above Earth and above the region where the Northern Lights form.

“We can now determine exactly where the emission is coming from,” Mutel said.

Our planet is also known to hum, a mysterious low-frequency sound thought to be caused by the churning ocean or the roiling atmosphere.

This cacophony of radio static from Earth is known as Auroral Kilometric Radiation (so-called because the wavelength of the emission is typically kilometers long). AKR is generated when fast-moving particles boil off the sun, gush into space, and then get manhandled by Earth’s magnetic field. The same circumstance accounts for the aurora borealis — those ghostly celestial displays that quietly amuse bored Canadians and insomnious polar bears.

But AKR, which has been in the news lately, has caught the notice of many space fans. They see it as just the sort of signal that could tip off aliens about Earth’s existence, a kind of radio fingerprint of our world. And if that’s possible, then perhaps we might use our radio telescopes to detect the AKR billowing off ET’s planet.

Adding to the allure, AKR is no pipsqueak signal: The power involved is measured in millions of watts.

So, could aliens be tuning into this, the most powerful radio transmitter on Earth?

In principle they could, but in practice this would be tougher than a three-dollar steak. One problem for any extraterrestrial listeners is confusion with other solar system emitters. Both the sun and Jupiter — each of which have magnetic fields many thousands of times stronger than Earth’s — belch more powerful natural signals into space than we do. (Mercury, Saturn, Uranus and Neptune are also members of this cosmic chorus.) The aliens would have to wield highly directional antenna arrays to pick out Earth from this noisy crowd.

Of course, the aliens may have such sophisticated instruments. But we don’t. Our best low-frequency radio telescopes couldn’t find an alien Earth’s AKR emissions. Even so, radio astronomers are still hoping to detect the static from so-called “hot Jupiters” around nearby stars. Being so close to their suns, these blistering behemoths would be showered by charged particles. The particles would twist and shout once they got embroiled in the planet’s magnetic field, producing signals that are many thousands of times more powerful than the AKR from our own planet. But hot Jupiters are a special case.

So you might wonder, if finding multi-megawatt natural transmissions from Earth-like worlds is difficult, why do we bother to look for ET’s radio broadcasts with our SETI experiments? The answer is two-fold: First, deliberate transmissions could be far more tightly beamed (thereby wasting less energy on a signal that largely dissipates into empty space). Second, an intentional radio ping might be narrow-band.

The last point is important. Nature, lacking a degree in electrical engineering, produces radio signals that are wastefully wide-band. Think of lightning: the color is close to white (in other words, the light’s spread over all wavelengths), and if you have your AM radio on during a storm, you’ll note that the associated radio crackle is also wide-band. You can hear it no matter where you tune. While there are exceptions to this general behavior (both interstellar masers and the 21 cm emission from neutral hydrogen come to mind), it’s usually the case that nature’s radio transmissions — from quasars to pulsars to AKR — are spread all over the dial.

On the other hand, ET, benefitting from higher education, could build a transmitter capable of corralling a lot of energy into a very narrow band. This would produce a signal that’s far easier to detect than nature’s broadcast splatter. If you do the numbers, you’ll see that — at light-years distance – AKR, despite all the megawatts, is enormously harder to find than even a modest radar installation.

So yes, it’s interesting that an Earth-like planet will have its own, thoroughly natural radio signature. Indeed, as our radio telescopes improve, this is one more phenomenon that legions of grad students will no doubt study. But it is the deliberate, carefully-engineered signal — a signal able to stand head and shoulders above this noisy background — that could reveal something far more precious than the rowdy interplay of magnetic fields and charged particles: the presence of intelligent life.