Oil price 'may hit $200 a barrel'

The price of crude oil could soar to $200 a barrel in as little as six months, as supply continues to struggle to meet demand, a report has warned.

Goldman Sachs energy strategist Argun Murti made the warning as benchmark US light crude passed the $123 mark for the first time.

Surging demand was increasingly likely to create a "super-spike" past $200 in six months-to-two years' time, he said.

Oil prices have now risen by 25% in the

last four months and 400% since 2001.

US sweet, light crude hit an all-time peak of $123.53 (£63.25) on Wednesday, while London Brent crude jumped to $122.32.

Mr Murti correctly predicted three years ago - when oil was about $55 a barrel - that it would pass $100, which it reached for the first time in January of this year.

Chinese demand

Soaring global demand for oil is being led by China's continuing economic boom and, to a lesser extent, by India's rapid economic expansion.

Both are now increasingly competing with the US, the European Union and Japan for the lion's share of global oil production.

This additional demand comes at a time of continuing production problems in a number of oil-producing nations.

Production is down in Nigeria after the latest attacks on pipelines this week by anti-government militants, while Iraqi exports through the north of the country have been hit by renewed cross-border raids by Turkish forces against Kurdish insurgents.

Oil prices are also rising as the key US summer driving season approaches.

Economists warn that continuing high oil prices will impact on the global economy, hitting growth and fuelling inflation.

Serbia poll fuels Kosovo tension

Serbia is holding an early general election on Sunday - and 300 polling stations will open in Kosovo, despite the declaration of independence in February.

The Serbs insist that Kosovo is still part of Serbia, and that no-one has the right to stop them flexing their democratic muscles.

The Kosovan government and the UN mission in Kosovo protest that only the UN has the right to organise local elections in Kosovo - and will not recognise the results. But they have pledged not to stop the elections taking place.

"Kosovo is an independent state and we act according to that position," deputy prime minister Hajredin Kuci told the BBC.

"Unfortunately people in Serbia, especially the government of Serbia, are trying to use Serbs in Kosovo not as a bridge for co-operation between Serbia and Kosovo, but as a movement for the integration of Kosovo into Serbia...

"In any case, we will not give them the chance to build up new institutions according to the result."

But that is exactly what the Serbs intend to do.

"These elections are important for us for many reasons," said Jovan Stojanovic, a candidate of the Movement for the Survival of Serbs, in Caglavica.

"For the first time in nine years (since Nato replaced Serbian security forces in the province in 1999) we are going to choose legitimate local representatives."

Displaced communities

One of the many strange features about this election is that they are being organised according to the old, pre-1999 municipal boundaries.

So Mr Stojanovic is standing for a position on the Pristina city council, which will sit in exile in Gracanica - a parallel institution to the Albanian city council of Pristina elected in the Kosovan local elections last November. Kosovan Serbs boycotted that vote.

"In the local elections we're choosing people who will organise all the main areas of our lives," said Zvonimir Stevic, candidate for the Socialist Party of Serbia in the same region.

"They are the people who will represent us in negotiations with the international community, and with our neighbours the Albanians as well."

Many Serbs in Kosovo's enclaves say that whatever the disagreements over the territory's status, whether it is now independent or not, it is high time Albanians and Serbs sat down and solved the real problems together - local problems like the daily power cuts, rubbish collection, water supply, sewage.

Serb refugees from Kosovo are being encouraged to vote for the council of the town and village they fled from.

There are only a few hundred Serbs still living in Pristina. But there are around 6,000 Serbs displaced from Pristina on the voting register in central Kosovo, and a further 25,000 Serbs from Pristina now living in Serbia who can vote for the Pristina city council.

Deepening split?

Another oddity is that Albanians who fled to Kosovo from the Presevo Valley in southern Serbia in 2001, and now live as refugees in Kosovo, are being encouraged to cross back into Serbia this weekend, to vote for ethnic Albanian parties standing in the Serbian election. They currently have only one deputy in the Serbian parliament. Special buses are being laid on for the Albanians to go and vote in Serbia.

No one appears quite sure what happens when the voting dies down.

The biggest challenge to Kosovan independence would come if an idea put forward by Marko Jaksic, a prominent Serb nationalist standing for the Serbian Radical Party in northern Kosovo, is adopted by the new government in Belgrade.

He has proposed the formation of a Serbian parliament in Kosovo, made up of those elected this weekend. "Serbs in Kosovo need a representative body through which they will realise their legal and legitimate rights," he told the Reuters news agency this week.

In Pristina a rally against the Serbian elections, organised by student leader Albin Kurti's Self-determination movement, passed off peacefully on Friday.

Participants dumped rubbish outside the government building, to demonstrate their anger at what they see as the failure of both the government and UN mission to prevent the Serb voting.

They say the elections will serve to further partition Kosovo into Serb and Albanian areas, and will strengthen Serb ties to Belgrade, while weakening and undermining their ties to Pristina.

Olympic flame lit at Everest peak

Chinese climbers bearing the Olympic flame have reached the summit of Everest, the world's highest mountain.

Chinese television showed the team of climbers, carrying special high-altitude torches, reaching the summit at 0920 local time (0120 GMT).

Huddled in the snow they unfurled flags and cheered for the cameras.

Correspondents say China is hoping the dramatic feat will counter some of the damaging publicity from the protests during the torch's international relay.

Perfect conditions

The team - made up of both Tibetans and Han Chinese - set off several hours before dawn from their camp at 8,300m.

Everest Olympic torch diary Nepal lifts Everest ban

Low winds and a clear sky provided perfect climbing conditions for the six-hour ascent of the 8,848m (29,030 feet) high summit.

At the weekend heavy snowfall had prevented a previous attempt, and badly damaged several of the high-altitude camps.

The climbers, dressed in red padded anoraks bearing the Beijing Olympic logo, passed the flame between several torches as they traversed the icy slopes on the final steps to the summit.

Holding up Chinese and Olympic flags, they cheered "Beijing welcomes you!" and "One World, One Dream", the official slogan of the Beijing Olympics.

The first and last of the torch-bearers were Tibetan women.

CHINA RELAY CITIES IN FOCUS Use the map to see the full Olympic torch relay route or read about some of the key cities: Full route map, Hong Kong, Guangzhou, Xiamen, Jinggangshan, Shanghai, Nanjing, Huangshan, Three Gorges, Kaili, Lhasa, Urumqi, Xian, Yanji, Weihai, Qufu, Anyang, Beijing.

"We have lit this torch on the top of the world for harmony and peace," said one of the mountaineers.

Security was very tight for the event, with other climbers being banned from the top of Mount Everest, which is known in China as Mount Qomolangma.

Both China and Nepal sealed off their sides of the mountain and the ascent organisers kept the exact plans a secret because of fears it might draw protests from pro-Tibet activists.

Human rights activists have been angered by the crackdown on anti-Beijing protests in Tibetan areas of China in March that turned violent.

The main Olympic torch, which is running separately, is continuing its relay through China.

It was carried through the southern city of Guangzhou on Wednesday past cheering crowds with no reports of disruptions.

It is scheduled to visit every province in China before arriving in Beijing several days before the Olympics begin on 8 August.

The international leg of the torch's tour was marred by protests in several cities - including London, Paris and San Francisco - by activists critical of China's human rights record.

Obama takes super-delegate lead

Democratic presidential candidate Barack Obama has overtaken his rival Hillary Clinton for the first time in endorsements from super-delegates.

Four super-delegates - party and elected officials - pledged to support Mr Obama, including two who previously supported Mrs Clinton.

Mr Obama also has a strong lead in delegates won in state primary and caucus votes.

The Democratic super-delegates look set to decide who wins the nomination.

Added to the nine who came out in support of Barack Obama on Friday, he now has 275 super-delegates to Mrs Clinton's 271.

'Likely nominee'

Mr Obama won a convincing victory in Tuesday's North Carolina primary; while Mrs Clinton narrowly won in Indiana.

Six more states hold primaries before the Democratic Party officially declares at its nominating convention in August who will take on presumptive Republican candidate John McCain.

The nearly 800 super-delegates automatically attend the Denver convention and can vote for whomever they choose.

Mrs Clinton held a massive lead in super-delegate support before the party's first primary in Iowa in January.

But a string of wins for Mr Obama has convinced many of them to come out in his favour.

Unity stressed

On Friday, former Democratic US presidential hopeful John Edwards said that Mr Obama is now the party's "likely presidential nominee".

But he stopped short of actually endorsing Mr Obama.

With fears mounting that the long, indecisive campaign may be fatally dividing the party, both candidates have been careful to say that they will work to unify Democrats before November's election.

"I want to go into the general election... with the party unified and ready to take on what I think is a wrong-headed vision of where the country should go," said Mr Obama from Bend, Oregon.

Although Mrs Clinton has said the nominating race is not over, she also said Democrats would come together against the Republicans no matter who wins.

"What I hear and what I see is all about how we're going to finish this nominating contest which we will do," she said at a New York fund-raiser.

"Then we will have a nominee, and we will have a unified democratic party, and we will stand together and we will defeat John McCain in November and go on to the White House."

Mrs Clinton is favoured to win the next primary in West Virginia on Tuesday. Then Oregon and Kentucky vote on 20 May.

All About Supernovas

A supernova is essentially the explosion of a star in outer space. During a supernova occurrence, a star’s luminosity is increased by as much 20 times as the bulk of the star’s mass is blown away at an extremely high velocity. Supernova remnants, including the signature bright light they leave behind, can often be seen in the night sky by the naked eye for several weeks as it gradually diminishes.

There are several different kinds of supernovae, which are believed to be caused by two distinct sources. One possible cause for Supernova occurrences results from a star halting its generation of fusion energy from fusing the nuclei of atoms in its core, causing it to collapse under the force of its own gravity. Another possible source occurs when a white dwarf star accumulates material from another nearby star until it nears its Chandrasekhar limit and undergoes runaway nuclear fusion in its interior, ultimately leading to its destruction.

Supernovas are generally classified according to the lines of different chemical elements that appear in their spectra, the first of which is hydrogen. If a supernova's spectrum contains a hydrogen line, it is classified as Type II, if this line of hydrogen is not present the Supernova is Type I. Within the Type I and Type II classifications are five sub-classifications that include Type Ia, Type Ib, Type Ic, Type II-P and Type II-L, each having its own distinct chemical and physical characteristics.

Latest Sun Flare Put at X28, Strongest on Record

NOAA's Space Environment Center (SEC) has classified this flare as an X28, making it in fact the strongest ever recorded. A source told SPACE.com that the SEC is aware other scientists still think the flare was even stronger. The article below remains as it originally appeared. - RRB

A flare released by the Sun on Tuesday could be the most powerful ever witnessed, a monster X-ray eruption twice as strong as anything detected since satellites were capable of spotting them starting in the mid-1970s

The strongest flares on record, in 1989 and 2001, were rated at X20. This one is at least that powerful, scientists say. But because it saturated the X-ray detector aboard NOAA's GOES satellite that monitors the Sun, a full analysis has not been done.

The satellite was blinded for 11 minutes.

Craig DeForest, a solar physicist at the Southwest Research Institute, said others in his field are discussing the possibility that Tuesday's flare was an X40.

"I'd take a stand and say it appears to be about X40 based on extrapolation of the X-ray flux into the saturated period," DeForest told SPACE.com.

That estimate may even be conservative, he said.

The flare leapt from a sunspot that is rotating off the visible face of the Sun, so its effects were not directed squarely at Earth. Nonetheless, a radio blackout occurred at many wavelengths as the storm's initial radiation arrived just minutes after the eruption. Radio blackouts are ranked from R1 to R5 by NOAA's Space Environment Center, the space counterpart to the National Weather Service.

"This is an R-5 extreme event," said SEC forecaster Bill Murtagh. "They don't get much bigger than this."

Paal Brekke, deputy project scientist for the SOHO spacecraft, which monitors the Sun, also told SPACE.com the outburst could be as strong as X20 "or much higher."

At least X20

The SEC is still evaluating the flare's ranking. For now, they are calling it an X20+, indicating that it is indeed the most powerful on record. The only known event that might outrank it is an 1859 solar storm that zapped telegraph lines in an era when solar monitoring could not provide an evaluation of a flare's strength.

The radiation flare was accompanied by a coronal mass ejection (CME), an expanding cloud of charged particles -- actual matter that moves at supersonic speeds but not as fast as light. Had this CME been aimed at Earth, scientists would have feared a potential space storm unlike anything seen in the Space Age.

As it is, the expanding cloud is expected to provide a glancing blow sometime Thursday.

The storm, if it arrives, will not likely be major, forecasters say. But as with all space weather, satellites and communication systems will be at risk of disruption or damage. Colorful sky lights called auroras may be active at high latitudes and possibly into northern U.S. states and Europe.

More to come?

Tuesday's flare was generated by Sunspot 486, which is about 15 times the size of Earth.

Sunspots are dark, cooler regions of the solar surface, areas of pent-up magnetic activity. They're a bit like caps on a shaken soda bottle, and upwelling matter and energy can blow at any moment. Scientists cannot predict when a flare will occur.

During the past two weeks, number 486 and two other large sunspots set off nine other major flares. It was one of the stormiest periods of activity ever witnessed, all experts agree. The number of intense flares, some shooting out within a day of another, was unprecedented. Auroras were seen as far south as Texas and Florida.

The second strongest flare in this historic two-week series was an X17 event on Oct. 28. It was aimed at Earth and generated severe geomagnetic storming when it blew past the planet less than 24 hours later.

A period of relative calm is now expected on the solar surface. But another round is possible.

The Sun spins once on its axis once every 25 days at its equator, carrying sunspots around. Sunspots can last days or weeks. Any of the three that have rotated off the right side of the Sun could return in about two weeks on the left side and, possibly, send more major storms toward Earth.

Solar Surprise: Electrified Wind Has Deep Origins

Constantly buffeting the Earth and its satellites, the solar wind can gust from 750,000 to 1.5 million mph. Astronomers would like to predict the dramatic changes in this constant barrage of charged particles so as to better protect the craft that orbit Earth.

Recent research shows that the solar speeds can be accurately measured by observing a relatively deep layer of the Sun's atmosphere - far beneath where the winds are thought to originate.

In what could be a boon to space weather forecasts, scientists discovered a relation between solar wind speed and fluctuations in the chromosphere - a region a few thousand miles thick on the outer surface of the Sun.

The findings were a surprise because the solar wind appears to blow out of the lower portions of the hot, wispy corona, which extends for millions of miles above the chromosphere.

"It's like discovering that the source of the river Nile is another 500 miles inland," said Scott McIntosh of the Southwest Research Institute.

The solar wind is composed of electrically charged particles that are partly accelerated by magnetic fields that permeate the corona.

The magnetic field is called "closed" when it curls back onto the Sun's surface. The solar wind is slower and denser coming out of a closed region.

But the fastest wind particles are channeled down "coronal holes" - places where the magnetic field lines point out into space, in a configuration called "open." Coronal holes can be seen as large, dark spots in X-ray images of the corona, which generally emits copious amounts of X-rays because it is millions of degrees Fahrenheit.

The chromosphere is much cooler than the corona and can only be seen during an eclipse. The other times it is overwhelmed by the bright photosphere - the layer just below the chromosphere, where majority of sunlight comes from.

Using NASA's Transition Region and Coronal Explorer (TRACE) spacecraft, McIntosh and his collaborators measured stellar sound waves traveling through the chromosphere and determined that this layer was stretched thin just below coronal holes.

"This kind of flummoxed us," McIntosh told Space.com. "We thought the chromosphere shouldn't know anything about the coronal hole above it."

To further investigate this correlation, the scientists compared the chromosphere structure to the speed of the corresponding wind as it whisked by the Earth. It turned out the solar wind velocity could be estimated accurately just by measuring the chromosphere below which it originated.

The discovery is expected to improve space weather forecasts. This is vital to communication satellites, which are vulnerable to space storms. In the future, if humans venture back to the Moon and on to Mars, broader and better cosmic storm predictions will be necessary.

The worst radiation events arise out of coronal mass ejections (CMEs) - when the Sun expels billions of tons of solar wind particles in one blast. A CME can accelerate particles as it plows through the solar wind in front of it. By knowing the speed and density of solar wind "fronts" around the Sun, scientists may predict how severe the eventual storm will be.

"Just as knowing more details about the atmosphere helps to predict the intensity of a hurricane, knowing the speed of the solar wind helps to determine the intensity of space radiation storms from CMEs," said Robert Leamon of NASA's Goddard Space Flight Center.

McIntosh and Leamon are the authors of a paper describing the research in the May 10 issue of the Astrophysical Journal.

Until now, much of our information about the solar wind and storms has come from relatively nearby spacecraft like ACE, WIND, and SOHO.

"This spacecraft fleet was placed along the Earth-Sun line because we need to know about the space weather coming our way," said Joe Gurman from Goddard. "However, compared to the size of our solar system, this is a very narrow range; it's like looking through a soda straw."

But with the correlation between the solar wind and the chromosphere, scientists will be able to use the data from TRACE to forecast the weather in half of the solar system, they said.

Shock to the (Solar) System: Coronal Mass Ejection Tracked to Saturn

in a dramatic proof that solar coronal mass ejection (CME) events affect even the outermost portions of the Solar System, scientists have traced an interplanetary shock from the Sun to Earth to Jupiter to Saturn.

They report the discovery of a strong transient polar emission on Saturn, tentatively attributed to the passage of an interplanetary shock. The shock-triggered events were first seen here on Earth, where auroral storms were recorded. Next, auroral activity on Jupiter was seen to be strongly enhanced. Finally, the unusual polar emission on Saturn was noted. This sequence of events establishes that shocks retain their ability to trigger planetary auroral activity throughout the Solar System.

In their 1992 science fiction book Flare, Roger Zelazny and Thomas T. Thomas chronicle the effects of a huge solar flare as it wreaks havoc across the inhabited worlds and space stations of the solar system. The effects of this event on the orbiting EverRest Cryotorium were described as follows:

The EverRest Cryotorium orbited low over the Earth ... forgotten by a handful of individuals ... some who worked daily in the NASA Department of Decaying Orbital Artifacts - the "Trash Squad."

However, with the unaccustomed surge of electromagnetic noise that was echoing throughout the inner solar system, and with the ensuing panic as normmaly talkative human beings discovered that their multiplex communications system was effectively blanked out, no one happened to be looking at the sky.

Unappreciated by these people, for the past twenty minutes the ionosphere 500 kilometers uner the EverRest's keel had been absorbing huge blasts of intense radiation from the solar flare.

The air density at such a height above the Earth's surface is quite thin: ranging from two millionths down to five billionths of a gram per cubic meter... the molecular fragments remain at their current altitude because the collective collisions of their gas pressure, energized by the sun's radiation, propel them upwards against the pull of gravity... heat the gas and you increase its pressure. Without confining walls or a steel tank to contain it, the volume of gas expands.

...the continuous influx of high-energy radiation had trippled the ambient temperature of the lower ionosphere. The resulting swell in the volume of gas pushed upward, increasing the density of material in EverRest's immediate vicinity by about fifty times.

The effect was immediate.

The orbiting hull reacted as if it had hit a wall.
(Read more from Flare)

Solar flares occur when magnetic energy built up in the solar photosphere is suddenly released. Radiation across the entire electromagnetic spectrum is released; the energy released can equal that of a million 100 megaton hydrogen bombs exploding at the same time. The first flare recorded occurred in 1859. A solar flare in 1989 blacked out all of Quebec, Canada. Solar flares in 1998 knocked out the Galaxy 4 satellite, causing eighty percent of the pagers in North America to fall silent.

The sun's corona is highest region of the solar atmosphere; it can be seen during a total eclipse as a large halo of white, glowing gas extending several solar radii from the solar disk. A special telescope called a coronagraph that artificially eclipses the sun's disk is used to study the solar corona on a regular basis. A coronal mass ejection (CME) can occur without a flare, although they are often associated. A CME can carry up to 10 billion tons of electrified gas traveling at speeds of up to 2,000 kilometers per second. Fortunately, our planet's magnetic field serves as shield against these storms.

The results were published in a letter to the journal nature by Renee Prange, Laurent Pallier and Regis Courtin (LESIA, Observatoire de Paris); Kenneth C. Hansen (Department of Atmospheric, Oceanic and Space Sciences, University of Michigan); Russ Howard and Angelos Vourlidas (Naval Research Laboratory); and Chris Parkinson (California Institute of Technology, JPL and the NASA Astrobiology Institute). Read An interplanetary shock traced by planetary auroral storms from the Sun to Saturn.

Inside the Sun: What Triggers Major Eruptions

A detailed study of a huge solar eruption reveals that a series of smaller explosions combined in a domino effect to fuel the blast.

The findings improve understanding of the Sun's most powerful events and could lead to better forecasting of the tempests, researchers said.

Scientists studied data collected from a radiation flare on the Sun on July 15, 2002. The eruption, ranked as an X-7, was one of the most powerful in recent times. The flare was accompanied by a coronal mass ejection, which is a colossal discharge of electrified gas called plasma. The event was 5,000 million times more powerful than an atomic bomb.

Scientists don't know exactly what triggers such eruptions. They are associated with strong magnetic fields, however, and emanate from sunspots, which are cooler regions of the Sun that correspond to bottled-up magnetic energy.

"Sunspots are at the surface of the Sun, and are essentially the footprints of the magnetic field," explained Louise Harra of the Mullard Space Science Laboratory at University College London. "The magnetic field reaches into the outer atmosphere in the same way as for example a bar magnet has a magnetic field around it."

Researchers had thought the big eruptions are created when magnetic field lines from the core of a sunspot become tangled and reconnect high in solar atmosphere, or corona. The new study contradicts that assumption.

X-7 flare started when plasma from below the Sun's surface broke suddenly through.

"Below the surface of the Sun a dynamo process is working creating magnetic field," Harra explained in an email interview. "When this becomes buoyant it can rise to the surface of the Sun, and into the atmosphere."

The plasma collided with a strong magnetic field at the surface, and the interaction triggered release of "phenomenal amounts of energy," the researchers concluded. There were three eruptions, each triggering the next.

The gas was heated to 36 million degrees Fahrenheit (20 million Celsius) before being flung up into the solar atmosphere at 90,000 mph (40 kilometers per second).

"We have observed the flows of hot gas for the first time, enabling us to see that several small flares combine to create a major explosion," Harra said. "This may eventually enable us to predict large flares before they erupt."

Not all solar flares are accompanied by coronal mass ejections, and nobody knows for sure why.

"It must be a combination of the magnetic field strength and the magnetic configuration that will allow field lines to be opened and hence the release of gas," Harra said.

The observations were made with SOHO spacecraft, a joint project of NASA and the European Space Agency. The results were presented last week at a meeting of the Royal Astronomical Society.

Solar Flare Hits Earth and Mars

Powerful radiation bursts from solar flares unleashed by the Sun in 2001 struck Earth and Mars within minutes of each other and affected the upper atmospheres of both planets in similar ways, a new study finds.

The solar flare measurements were made by NASA's Mars Global Surveyor (MGS) spacecraft, which has orbited the red planet since 1999, and by satellites circling Earth.

The finding, detailed in the Feb. 24 issue of the journal Science, could have implications for future Mars missions, since solar flares striking Earth have been known to affect communication and navigation satellites and are often followed by other types of space particle storms that are potentially dangerous for astronauts.

Double bombardments

On April 15, 2001, satellites around Earth recorded the creation of large amounts of electrons and charged particles, called ions, in the planet's ionosphere from ultraviolet radiation and X-rays unleashed by a solar flare. The same thing happened again on April 26.

The ionosphere is the part of a planet's upper atmosphere that absorbs solar radiation.

"The energy of the X-ray photons is so great that once absorbed by the molecule they eject an electron from the atom, leaving an ion behind," explained study member Paul Withers from Boston University.

During both solar flare events, the MGS spacecraft recorded similar alterations in the Martian ionosphere just minutes after the flares struck Earth.

The finding confirms that solar flare radiation affects the ionospheres of Earth and Mars in similar ways, despite the different chemical compositions of the planets' atmospheres. Earth's ionosphere is populated largely by oxygen and nitrogen, while the Martian ionosphere contains mostly carbon dioxide.

"Since the Martian atmosphere is different in some ways, we can take theories that have been developed in the terrestrial case and test whether they work on Mars as well or whether there are areas that need improving," Withers told SPACE.com.

"If you study the effect exclusively on terrestrial conditions, you might not understand the general physical principle underlying [solar flares] but only a specific case of how it works," he said.

Implications for Mars missions

Work on solar flares could prove important for future missions to Mars that might eventually be part of a plan outlined by President Bush in 2004. On Earth, solar flares have been known to damage or skew results from satellites such as those making up the Global Positioning System (GPS).

"If humans go to Mars and have a similar positioning system there, knowing about ionosphere effects will be important," Withers said.

While solar flare radiation is typically not dangerous to humans if they are are at Earth's surface or have proper protection, the flares can be followed by streams of high-speed particles called protons. These "proton storms" are potentially lethal to astronauts and have been known to reach Earth in as little as 15 minutes.

Solar flares can also fuel giant clouds of electrified gas, called coronal mass ejections, which can billow into the solar system and overtake Earth in a matter of hours or days.

These two space phenomena are harder to shield against and can be dangerous to astronauts. On Jan. 20, 2005, the International Space Station was struck by a proton storm so powerful that its crew had to take shelter in the bulkier Russian side of the station, in a section designed with such storms in mind.

Also, radiation from solar flares, combined with the normal doses of radiation that astronauts are routinely exposed to while in space, could put astronauts over the estimated limit as outlined under NASA guidelines.

Unlike Earth, which has a strong magnetic field and a dense atmosphere to deflect most solar flare radiation, Mars is relatively naked to space weather.

Sun's Activity Increased in Past Century, Study Confirms

The energy output from the Sun has increased significantly during the 20th century, according to a new study.

Many studies have attempted to determine whether there is an upward trend in the average magnitude of sunspots and solar flares over time, but few firm conclusions have been reached.

Now, an international team of researchers led by Ilya Usoskin of the Sodankylä Geophysical Observatory at the University of Oulu, Finland, may have the answer. They examined meteorites that had fallen to Earth over the past 240 years. By analyzing the amount of titanium 44, a radioactive isotope, the team found a significant increase in the Sun's radioactive output during the 20th century.

Over the past few decades, however, they found the solar activity has stabilized at this higher-than-historic level.

Prior research relied on measurements of certain radioactive elements within tree rings and in the ice sheets covering Greenland and Antarctica, which can be altered by terrestrial processes, not just by solar activity. The isotope measured in the new study is not affected by conditions on Earth.

The results, detailed in this week's issue of the journal Astronomy & Astrophysics Letters, "confirm that there was indeed an increase in solar activity over the last 100 years or so," Usoskin told SPACE.com.

The average global temperature at Earth's surface has risen by about 1 degree Fahrenheit since 1880. Some scientists debate whether the increase is part of a natural climate cycle or the result of greenhouse gases produced by cars and industrial processes.

The Sun's impact on climate has only recently been investigated. Recent studies show that an increase in solar output can cause short-term changes in Earth's climate, but there is no firm evidence linking solar activity with long-term climate effects.

The rise in solar activity at the beginning of the last century through the 1950s or so matches with the increase in global temperatures, Usoskin said. But the link doesn't hold up from about the 1970s to present.

"During the last few decades, the solar activity is not increasing. It has stabilized at a high level, but the Earth's climate still shows a tendency toward increasing temperatures," Usoskin explained.

He suspects even if there were a link between the Sun's activity and global climate, other factors must have dominated during the last few decades, including the increase of greenhouse gases in the atmosphere.

Sun's Next Stormy Cycle Starts

Astronomers say the Sun has begun its next cycle of activity, part of an 11-year ebb and flow in sunspots and solar flares.

Solar activity is near the low point in the cycle now. Few sunspots appear and solar flares are rare. But on July 31, a tiny sunspot appeared and then vanished after a few hours. It was a normal event, except that it was magnetically backward.

"We've been waiting for this," said David Hathaway, a solar physicist at the Marshall Space Flight in Huntsville, Alabama. "A backward sunspot is a sign that the next solar cycle is beginning."

Two lines of evidence

Sunspots are areas of strong magnetic activity, where material wells up from below. The dark spots are like tops on a soda bottle, and sometimes they erupt and send bubbles of superheated gas, called plasma, into space.

This sunspot had a south-north orientation in a region of the Sun where spots would normally be oriented north-south.

"We're near the end of Solar Cycle 23, which peaked way back in 2001," Hathaway said. Cycle 24 should begin "any time now," he said, adding that it might have begun on July 31.

The tiny, backward sunspot was at 13-degrees south latitude. Cycle-heralding sunspots are usually closer to the Sun's midsection, between 30 degrees North and 30 degrees South. So Hathaway is not certain the new cycle has begun. "But it looks promising," he said.

Another group of researchers today announced that the cycle had indeed begun. That team, using the Synoptic Optical Long-term Investigations of the Sun (SOLIS) facility built by the National Solar Observatory at Kitt Peak, Arizona, detected small magnetic eruptions near the Sun's poles that they say signal the new cycle's stars.

Storminess ahead

The peak of Cycle 23 was not particularly noteworthy, though a record-setting solar flare came as part of a string of storms struck our planet in November of 2003-actually well past the peak of the cycle.

Astronomers think Cycle 24 could be a strong one based on historical records and computer projections.

Enhanced activity means satellites and even power grids on Earth are at risk of electrical malfunction. Solar storms spew charged particles into space, and when they interact with Earth's protective magnetic field, electrical charges can dip into the lower atmosphere and even to the ground.

It will likely be many months and perhaps years before the new cycle builds steam and serious storminess ensues.

NASA plans later this month to launch a new pair of probes, called STEREO, to better monitor solar activity through the next cycle.

All About Solar Flares

A solar flare is a thunderous explosion that occurs in the solar corona and chromosphere within the atmosphere of the Sun. The incredible energy level of a solar flare is equivalent to tens of millions of atomic bombs exploding at the same time!

Solar flares were first known to be occurring in 1859. Solar flare activity can vary from several per day to only a few a month, depending mostly upon the overall activity of the Sun as a whole. Solar activity generally varies on an 11-year cycle. At the peak of this “solar cycle” there are typically more sunspots on the surface of the Sun, which ultimately leads to more frequently occurring solar flares.

Solar flares are typically classified as A, B, C, M or X, depending upon the degree of their peak flux. Most solar flares occur in or around sun spots as the result of intense magnetic fields emerging from the Sun’s surface into the corona. The powerful energy commonly associated with solar flares can take as long as several days to build up, but only minutes to release.

During the occurrence of a solar flare, plasma is heated to tens of millions degrees Kelvin, while electrons, protons and heavier ions are accelerated to near the speed of light. Solar flares produce electromagnetic radiation across the electromagnetic spectrum at all wavelengths from long-wave radio to the shortest wavelength Gamma rays. Solar flares cannot typically be detected by the naked eye from the surface of the earth.

UFO Mysteries

A UFO is a general term used for any “unidentified flying object” in the sky which cannot be discerned by an observer . Most UFOs remain classified as so even after they have been investigated. The UFO phenomenon dates back as far as the beginning of recorded history, but UFO sightings have significantly increased since the mid 1940s.

From UFO videos to UFO pictures, stories and other real life accounts, thousands of people from all walks of life claim to have seen these mysterious aerial phantoms. Many UFO sightings turn out to be nothing at all, mere airplanes, meteors or comets; however, many sightings have gone unsolved for decades or even centuries.

The term “flying saucer” came into popular use after American Kenneth Arnold claimed a UFO sighting on June 24, 1947 near Mount Rainier, Washington. Arnold claimed to have seen as many as nine brightly lit objects soaring across the sky at speeds he estimated as up to 1200 miles per hour. Arnold also reported that the objects appeared to have a disc or “saucer” appearance. No final conclusion has ever been reached in the case.

One of the most famous UFO incidents to date also occurred in 1947 in Roswell, New Mexico. After unidentified debris was recovered from the property of a Roswell ranch, the Roswell Army Airfield issued a statement saying that a “flying disk” had been discovered. The airfield retracted the statement just hours later, claiming it was just a weather balloon. This sparked local and nation-wide rumors of an alleged government cover-up of an alien UFO that had crashed in the New Mexico desert. No definitive proof has been produced to this day to support that theory.

Huge Black Hole Catapulted Through Space

A colossal black hole has been spotted exiting its home galaxy, kicked out after a huge cosmic merger took place.

The event, seen for the first time, was announced today.

When two colliding galaxies finally merge, it is thought that the black holes at their cores may fuse together too. Astronomers have theorized that the resulting energy release could propel the new black hole from its parent galaxy out into space, but no one has found such an event.

"We have observed the pre-merger stages of black holes," said Stefanie Komossa of the Max Planck Institute for extraterrestrial Physics, part of the team that made the new discovery. "But we haven't seen the actual merger event."

Komossa and her team have now detected the consequences of such a merger: a 100-million-solar mass black hole in the process of leaving its home galaxy.

"The consequence was that the merged black hole, the final product, the new black hole was expelled from the galaxy," Komossa said. The team's results are detailed in the May 10 issue of the journal Astrophysical Journal Letters.

Black holes get a kick

Komossa explained that the theory behind these mergers follows from the observations that many galaxies have very massive black holes at their cores. If two galaxies with these black holes collide, "then it's sort of inevitable that these two black holes will come very close to each other."

The black holes may not merge right away though.

"One possibility is that for a long time they just orbit each other," like binary stars, Komossa told SPACE.com.

Eventually, the orbiting black holes might interact with a star or surrounding gas which could cause them to lose angular momentum. "That would be a way to push them ever-closer towards each other," Komossa said.

Eventually, the black holes would fuse, and "in the final coalescence, or merger, of these two black holes, a giant burst of gravitational waves is emitted," she said. "Since these waves are generally emitted in one preferred direction, the black hole is then kicked in the other direction."

The "kick" the black hole receives is akin to the recoil of a rifle. It can propel the black hole to speeds of up to several thousand kilometers per second, according theoretical simulations. The escaping black hole Komossa and her team observed was racing along at 5,900,000 mph (2,650 kilometers per second).

The pull of the galaxy's gravity is no match for these incredible speeds, and the black hole, "will inevitably go to intergalactic space," Komossa said.

Galactic evolution

In theory, these mergers and escapes would leave several black holes without galaxies and galaxies without black holes out in space.

Detecting black holes at the center of galaxies is a difficult process. Because their gravity is so powerful, light is trapped, which is why they're black. Only by looking at their effects on surrounding material are they presumed to exist, and this is typically done only with relatively nearby galaxies, so looking for a missing black hole in the center of a distant galaxy is a tricky prospect.

The evolution of black holes and galaxies is very closely linked, so what exactly the effect would be on the separated partners is uncertain and the subject of further research.

In simulations where a black hole receives a slightly weaker kick, it can't escape the galaxy's gravity, so it falls back and oscillates until it comes to rest again at the galaxy's core. Recent simulations of this situation showed that stellar orbits adjust to the yo-yoing black hole, "so it clearly has an effect on the core of the galaxy," Komossa said.

Young Galaxies Surprisingly Packed with Stars

Several newfound galaxies seen as they existed when the universe was young are packed with improbable numbers of stars.

Astronomers don't know what's going on.

The nine galaxies are 11 billion light-years away, which means the light astronomers are looking at left the galaxies 11 billion years ago, when the universe was less than 3 billion years old.

Each of the newly studied galaxies weighs about 200 billion times the mass of the sun yet is a mere 5,000 light-years across. Our Milky Way Galaxy stretches across 100,000 light-years of space.

The compact galaxies have been furiously forming stars; each contains as many stars as a typical large galaxy of today, the new observations reveal.

"Seeing the compact sizes of these galaxies is a puzzle," said Pieter G. van Dokkum of Yale University, who led the study. "No massive galaxy at this distance has ever been observed to be so compact."

Since no modern galaxies, that is galaxies in the nearby universe, are so compact, the scientists assume compact galaxies from the early universe must have gotten much larger as they matured beyond the snapshots of ancient time now being studied. But nobody knows how.

"They would have to change a lot over 11 billion years, growing five times bigger," van Dokkum said. "They could get larger by colliding with other galaxies, but such collisions may not be the complete answer."

Astronomers used NASA's Hubble Space Telescope and the W.M. Keck Observatory on Mauna Kea, Hawaii to make the new observations, which were announced today and were detailed in the April 10 issue of the Astrophysical Journal Letters.

Van Dokkum and his colleagues had previously studied the galaxies in 2006 with the Gemini South Telescope to determine their distances, and showed that the stars are a half a billion to a billion years old. The most massive stars had already exploded as supernovae.

One reason these galaxies were so dense, van Dokkum suggested, involves the interaction of dark matter and hydrogen gas in the nascent universe. Dark matter is an invisible form of matter that accounts for most of the universe's mass. Shortly after the theoretical Big Bang, the universe contained an uneven landscape of dark matter. Hydrogen gas became trapped in puddles of the invisible material, the thinking goes, and began spinning rapidly in dark matter's gravitational whirlpool, forming stars at a furious rate.

Based on the galaxies' mass, the astronomers estimated that the stars are spinning around their galactic disks at roughly 890,000 to 1 million mph (400 to 500 kilometers a second). Stars in today's galaxies, by contrast, are traveling at about half that speed because the setups are larger and rotate more slowly.

Hubble Photographs Dozens of Colliding Galaxies

A huge set of new Hubble Space Images show galactic collisions in action and the variety of peculiar forms that merging galaxies can take.

The series of 59 new photographs, released today on the 18^th anniversary of the Hubble Space Telescope's launch, are the largest collection of Hubble images ever released together.

Galaxy mergers are now known to be more common than was previously thought. They were even more common in the early universe than they are today. The early universe was smaller, so galaxies were closer together and therefore more prone to smash-ups. Even apparently isolated galaxies can show signs of past mergers in their internal structure.

Our own Milky Way contains the debris of the many smaller galaxies it has brushed against and devoured in the past. And it hasn't stopped munching away at its neighbors: It is currently absorbing the Sagittarius dwarf elliptical galaxy.

The Milky Way isn't the top predator though, as our giant neighbor, the Andromeda galaxy, is expected to devour the Milky Way in about two billion years. The future resulting elliptical galaxy has already been dubbed "Milkomeda."

Though colliding galaxies rush towards each other at hundreds of kilometers per hour, the interactions can take hundreds of millions of years to complete.

This game of celestial bumper cars is driven by the gravitational pulls that galaxies exert on one another. Typically the first sign of a collision is a bridge of matter connecting two galaxies as gravity's first gentle tugs tease out dust and gas. As the outer reaches of the galaxies begin to interact, long streamers of gas and dust, called tidal tails, sweep back to wrap around the galactic cores.

As the cores approach each other, the conflicting pull of matter from all directions can result in shockwaves that ripple through interstellar clouds. Gas and dust are siphoned off to fuel bursts of star formation that appear as blue knots of young stars. Given the vast distances between stars in a galaxy ­— the nearest star to us is 4.3 light-years away — stars rarely collide when galaxies merge.

The Hubble images capture galaxies in various stages of the collision process and show the variety of new and unusual shapes the mergers can create, including mergers that look like an owl in flight and a toothbrush.

Mars Features Resemble Hydrothermal Springs

There's a growing buzz in the astrobiology community that ancient hydrothermal springs may have been spotted on Mars.

Thanks to the eagle-eyed work of Carlton Allen and Dorothy Oehler of NASA's Johnson Space Center, "spring-like" mounds have been found in Vernal Crater in Arabia Terra on the red planet.

The high-powered zoom lens of NASA's Mars Reconnaissance Orbiter (MRO) has picked up the features - two possible ancient hydrothermal springs are viewed as light-toned, elliptical structures.

The martian features have a striking similarity to spring mounds here on Earth, such as those in Dalhousie, Australia.

The potential big news here is that, if true, hydrothermal spring deposits on Mars might preserve evidence of martian life. These features would not only have supplied energy-rich waters in which martian life may have evolved, but also would have provided warm, liquid water to martian life forms as the climate on the red planet became colder and drier.

At present, whether life has existed on Mars in the past or may still dwell there today, remains an open question.

Allen said more work is needed to better analyze these features and also look for other similar spots on Mars. In particular, use of MRO's Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) can sort out the composition of the features in Vernal Crater. However, due to the dusty nature of Arabia Terra, that has crimped mineralogical assessment of the mounds.

Meanwhile, the prospect of identifying ancient thermal springs on Mars would be a boost for astrobiologists, Allen and Oehler report.

These could be sites where martian life evolved, sought refuge as the climate on Mars became colder and drier...and where evidence of that life may be preserved.

Gasping for Breath in the Jurassic Era

The debate over climate change and its effects is often headline news. In the near future, scientists are concerned that the Earth will experience a continuing increase in global temperature. New research is showing that even if this increase is only a few degrees, it could have important repercussions for life on our planet.

Scientists from the Open University in the United Kingdom are studying climate change throughout Earth's history. Their results indicate how dangerous modern global climate change might be for the future of life on Earth. In a new study published in the journal Geology, the researchers examined layers of sedimentary rocks from the ocean floor in order to unravel the story of climate change during the early Jurassic period.

Oceans losing oxygen

During the Jurassic, abrupt global warming of between 9 and 18 Fahrenheit (5 and 10 degrees Celsius) was associated with severe environmental change. Many organisms went extinct and the global carbon cycle was thrown off balance. One of the most intriguing effects was that the oxygen content of the oceans became drastically reduced, and this caused many marine species to die off.

These intervals of reduced oxygen content in the oceans are now known as oceanic anoxic events, or OAEs. OAEs are associated with periods of global warming and have occurred a few times in Earth's history. In the recent study, researchers focused specifically on the Toarcian OAE, a well-documented OAE from the early Jurassic.

During OAEs, the remains of dead organisms and other organic matter accumulate on the ocean floor and became layers of organic-rich sediments. Today, scientists are examining the chemical and isotopic compositions of these sedimentary deposits in order to determine the actual extent to which the oceans became anoxic. By doing so, they have been able to draw connections between oxygen-depleted oceans and the disruption of Earth's carbon cycle.

The carbon cycle on Earth is one of the most important cycles for life as we know it. Carbon is a primary building block of life and is present in every living organism. In order for life to survive on our planet, carbon must cycle between the atmosphere, geosphere (land), hydrosphere (water) and biosphere (life). If the carbon cycle were to suddenly become disrupted, many forms of life on Earth would not survive. Even minor disruptions in the carbon cycle can have profound consequences for living organisms.

By studying organic-rich marine deposits from the Toarcian OAE, the Open University researchers were able to compare the oxygen levels of ancient seawater to the oceans of today. The sedimentary rocks contain molybdenum, whose isotopic composition is altered depending on how oxygenated the seawater was when the sediments formed. By studying how the isotopic composition of molybdenum changed during the Toarcian OAE, scientists have developed a unique way to trace fluctuations in the oxygen content of Earth's oceans.

The Open University team determined that major disruptions in the global carbon cycle during the Jurassic period were intimately linked with the development of anoxic oceans and with global warming. Ultimately, this ties global warming to the demise of numerous life forms on Earth millions of years ago. Additionally, the research is providing insight into how the Earth's oceans and atmosphere evolved over time.

Our climate in the balance

Modern studies of global climate change on Earth usually rely on computer modeling techniques. However, studying the history of our planet through geology can provide information on actual occurrences of climate change in the past.

Dr. Anthony Cohen, a member of the research team, commented: "The use of current computer models to try to predict the course of climate and environmental conditions in the longer term is uncertain because of our relatively poor understanding of the great complexity of the Earth's behaviour. In contrast, marine sedimentary records can provide quantifiable information about precisely how the Earth has responded to severe environmental change in the past. Therefore, these records may also provide valuable constraints for testing the reliability of predictions about environmental change that will continue to occur in the future as a result of man's activities."

Although the Toarcian OAE occurred roughly 183 million years ago, the findings of the recent study have important implications for our understanding of climate change today. The rates and magnitude of environmental change during ancient OAEs appear to have been similar to what we see occurring in modern times.

By studying OAEs, scientists are able to gain important clues about how climate change might impact life on Earth in the in the coming centuries. Hopefully, their work will lead to scientific solutions that could prevent the same devastating affects on the Earth's carbon cycle — and life itself — that were caused by global warming during the Jurassic period.

Home of Drifting Star Found

By listening to the "ringing" of a nearby planet-harboring star, astronomers have for the first time identified the birthplace of one of our galaxy's many drifting stars.

The yellow-orange star Iota Horologii, located 56 light-years away near the southern-sky constellation Horologium ("The Clock"), was discovered to harbor a planet about two times the size of Jupiter in 1999.

But until now, scientists were unable to identify the exact characteristics of the star, or where in the galaxy it had formed.

The star currently resides in the "Hyades stream," a large number of stars that move in the same direction, many of which are thought to be so-called "drifting stars" — stars that were displaced from their birthplace. The new method used by the team of astronomers to identify Iota Horologii's stellar parentage involves studying how sound waves move through a star.

The approach could be used to ID other orphaned stars — estimated to make up about 20 percent of the stars within 1,000 light-years of the sun — and shed more light on how these stars move in the galaxy.

Good vibrations

Sylvie Vauclair of the University of Toulouse in France and her team of astronomers used a technique called "asteroseismology" to unlock the elusive properties of the star.

"In the same way as geologists monitor how seismic waves generated by earthquakes propagate through the Earth and learn about the inner structure of our planet, it is possible to study sound waves running through a star," Vauclair explained.

This "ringing" of the star gives scientists information about the physical conditions in the star's interior. With observations taken from the HARPS spectrograph, which is mounted on the European Southern Observatory's 3.6-meter telescope at La Silla, Chile, up to 25 "notes" were identified by the team.

"You can analyze the sound and analyze the harmonies, and you can get the harmonies of the star," Vauclair said. "And different stars have different harmonies."

These notes gave the astronomers a precise portrait of the star: its temperature is 6,150 Kelvin, its mass is 1.25 times that of the Sun, and it is 625 million years old. It is also 1.5 times as metal-rich as the sun, which was the clue astronomers needed to figure out where the star came from — the Hyades cluster.

"Iota Horologii has the same metal abundance and age as the Hyades cluster," Vauclair said, adding that "the chance is really low that it's a coincidence."

The team's findings are detailed in a Letter to the Editor in the journal Astronomy and Astrophysics.

Drifters

Other stellar drifters inhabit these so-called "streams" that travel with the same velocity as nearby clusters, with some of them suspected to have formed in the cluster. In the Hyades stream, previous research has shown that "most of the stars have not been formed in the Hyades," Vauclair said. Only about 15 percent were estimated to come from the Hyades cluster.

"This guy [Iota Horologii] would be one of this 15 percent," Vauclair told SPACE.com. "I think it's the first star for which we have this result."

Vauclair says the star must have formed together with the other stars of the Hyades cluster, but then must have slowly drifted away, to its current spot more than 130 light-years from its birthplace.

Previous research has shown that quite a few stars follow unusual trajectories compared to most stars, which orbit the Milky Way's center. It is thought that the wanderers may be gravitationally stirred by the spiral arms of the galaxy, which could deflect the motions of the stars. The stars may eventually get sucked into other arrangements of stars with more normal paths around the galactic center, which is thought to have happened to most of the stars in the Hyades stream, Vauclair said.

Plenty of other clusters have associated streams, and the same method that Vauclair and her team used to ID Iota Horologii could be used to pinpoint where other stars came from, shedding light on how they got to where they are now, she said.

Long-Lived Lightning Storm Rages on Saturn

A monster storm spawning bolts of lightning 10,000 times more powerful than any seen on Earth is raging on the ringed planet Saturn.

The powerful electrical storm cropped up in Saturn's southern hemisphere five months ago, when it was first spotted by NASA's Cassini spacecraft, and has persevered to become the planet's longest continuously recorded tempest to date.

"We saw similar storms in 2004 and 2006 that each lasted for nearly a month, but this storm is longer-lived by far," said Georg Fischer, an associate with Cassini's radio and plasma wave science team at the University of Iowa, Iowa City, in a statement. "And it appeared after nearly two years during which we did not detect any electrical storm activity from Saturn."

Cassini's radio and plasma wave science instrument first picked up signals from the storm's lightning bursts on Nov. 27, 2007, with the probe's cameras catching their first visual glimpse on Dec. 6. Images of the storm show it as a smudge on Saturn's otherwise creamy cloud bands.

"The electrostatic radio outbursts have waxed and waned in intensity for five months now," Fischer said.

Electrical storms on Saturn are similar to thunderstorms on Earth, but much larger. They can span thousands of miles and generate radio bursts from lightning that can be thousands of times more powerful than Earthly lightning bolts, said mission scientists, who named a massive lightning storm in 2004 "Dragon."

The current electrical tempest is mired in a region of Saturn that mission scientists have dubbed "Storm Alley" because of its frequent and intense storms. Every few seconds the storm belches intense radio pulses consistent with lightning that can be detected even when the weather itself is over the horizon and out of direct view from Cassini.

Researchers hope that by tracking the Saturnian weather, they may gain new insights into the processes behind the planet's lightning, as well as how it changes as the seasons shift from summer to autumn in Saturn's southern hemisphere.

"In order to see the storm, the imaging cameras have to be looking at the right place at the right time, and whenever our cameras see the storm, the radio outbursts are there," said Ulyana Dyudina, a Cassini imaging team associate at the California Institute of Technology in Pasadena, Calif.

Cassini's onboard instruments have tracked the storm every 10 hours and 40 minutes, when Saturn's rotation brings it into view, though amateur astronomers are also watching over the tempest from Earth.

"Since Cassini's camera cannot track the storm every day, the amateur data are invaluable," said Fischer. "I am in continuous contact with astronomers from around the world."

Launched in 1997, Cassini arrived at Saturn in 2004 and has spotted a series of odd storms while studying the ringed planet and its many moons. The probe has captured views of a hurricane-like storm near the south pole of Saturn and recorded a massive lightning storm about 2,175 miles wide (3,500 kilometers) wide in 2006.

Earlier this year, managers for the international Cassini-Huygens mission, which includes NASA, and the European and Italian space agencies, extended the probe's $3.27 billion expedition by two additional years to 2010.

NASA Predicts Huge Cosmic Explosions

Astronomers are now able to predict when a certain type of star will let loose a powerful eruption.

The explosions occur on a neutron star, a city-sized remnant of a giant star that exploded in a supernova long ago and collapsed into a hyperdense ember. It now siphons material from a companion star while the two objects orbit each other every 3.8 hours.

The neutron star has incredibly strong gravity, so it sucks in some of the gas from the companion star's atmosphere. The gas spirals onto the neutron star, slowly building up on its surface until it heats up to a critical temperature. Suddenly, the gas at one small spot on the neutron star's surface ignites a powerful explosion, and the flame quickly spreads around the entire star.

"We found a clock that ticks slower and slower, and when it slows down too much, boom! The bomb explodes," said team leader Diego Altamirano of the University of Amsterdam in the Netherlands.

The explosion appears as a bright flash of X-rays.

The new study was done using NASA's Rossi X-ray Timing Explorer (RXTE) satellite.

The neutron star produces about 7 to 10 bursts per day. These explosions release more energy in 100 seconds than our sun radiates in an entire week. The energy is equivalent to 100 hydrogen bombs exploding simultaneously over each postage-stamp-size patch of the dying star's surface.

Scientists have observed thousands of similar bursts from about 80 different neutron stars, according to a NASA statement today. But until now, they had no way to predict when they would occur.

As gas gradually builds up on the neutron star's surface, the atoms that make up the gas slam together to form heavier atoms in a process known as fusion. Sometimes, the fusion occurs in a stable and almost perfectly repetitive fashion, producing a nearly regular X-ray signal known as a quasi-periodic oscillation (or QPO for short). Think of the QPO as a clock that ticks with near-perfect precision.

Scientists expect that the QPO clock should tick about once every two minutes (120 seconds). This is what Altamirano's team found when the astronomers observed the system with RXTE. But the team also found that the QPO clock starts ticking slower and slower as gas builds up on its surface. Whenever it slows down to one cycle every 125 seconds, the neutron star lets loose a powerful explosion.

"We can predict when these explosions are happening," Altamirano said.

This double-star system is called 4U 1636-53 and is about 20,000 light-years away. Of course that means the "predictions" involve explosions that actually occurred 20,000 years ago; the light is just now arriving.

"It's an exciting discovery," adds Tod Strohmayer of NASA's Goddard Space Flight Center in Greenbelt, Md. Strohmayer is an expert in neutron stars who was not involved in this study. He notes that the ticking of the QPO clock depends on the size and weight of the neutron star.

What Mars Fossils Might Look Like

Fossil microbes found along an iron-rich river in Spain reveal how signs of life could be preserved in minerals found on Mars. The discovery may help to equip the next generation Mars rover with the tools it would need to find evidence of past life on the planet.

The Rio Tinto arises from springs west of Seville. These springs percolate up through iron ores that were deposited by geothermal activity more than 200 million years ago. Spring water dissolves iron sulfide minerals from the ores, and this stains the river red. The iron sulfide minerals also dissociate to form sulfuric acid.

With a pH between 1.5 and 3, Rio Tinto is as sour as vinegar, yet it supports a surprising variety of life. Bacteria, algae, single-celled organisms called protists and fungi all thrive in the acid headwaters.

Rio Tinto has attracted the attention of exobiologists because this environment can create the iron mineral hematite, which has been found on Mars. On Earth, hematite only forms with liquid water. Since liquid water is seen as a prerequisite for life elsewhere, the mineral's presence on Mars tantalizes those who hope to find signs of life, past or present, on our neighboring planet.

By examining incipient fossils along Rio Tinto's shores and comparing them with much older fossils left on terraces now high above the river, David Fernàndez-Remolar of the Astrobiology Center in Torrejón de Ardoz, Spain and Andrew Knoll of Harvard University hope to better understand how similar minerals may have preserved a record of life on Mars.

Washed up

Pools at the edge of the river evaporate in the heat of the Spanish summer and leave behind mineral deposits. Over the years, as the river cuts down into the valley it creates rock terraces. The oldest and highest terraces formed 2 million years ago while the youngest are just a few centimeters above the surface.

When Fernàndez-Remolar and Knoll looked at those evaporating pools, they saw microbes that had become coated with nanoparticles of iron minerals that had precipitated out of the water. The most common mineral they observed was a rust-like iron oxide called goethite. Layers of fine-grained goethite surrounded the youngest fossil microbes, preserving the rod-like shapes of individual bacteria as well as filaments formed by bacterial colonies.

The minerals surrounding the fossils changed as the sediments cemented to form rock. Finely grained minerals encased fossils found in the youngest terrace, but those from a rock layer 700 to 800 years old had larger crystals. Over time, the minerals altered chemically as well. Rustlike goethite slowly loses hydrogen and oxygen atoms to become more stable hematite over time. In fossils from the oldest terraces, hematite had begun to replace the goethite. These findings were recently reported in the journal Icarus.

The iron-rich rocks of Mars's Meridiani Planum, where the rover Opportunity explores, may have formed through roughly similar geochemical processes, says planetary geologist Timothy Glotch of the State University of New York in Stony Brook.

"Rio Tinto is a decent analog for what we see on Mars," Glotch said, noting that spectral analyses suggest Martian hematite originally formed as goethite or a similar mineral that was later altered to hematite. "It's a story similar to what they see in Rio Tinto."

Visit required?

The Martian hematite rocks are far older than the Rio Tinto rocks. They may date back to as much as 3 to 4 billion years ago, a time that coincides with the earliest evolution of life on Earth. A lack of tectonic activity on Mars is likely to have left them relatively untransformed. For that reason, "Mars would be a very good place to look for preservation of microbial structures," Fernàndez-Remolar says.

Planetary scientist Carol Stoker of NASA's Ames Research Center at Moffett Field, California, agrees that if life was abundant when the Meridiani sediments formed, the fossils would likely be similarly preserved. But she isn't holding out much hope for any rover to find fossils. Successful identification of fossil life requires careful field work by geologists who select many of the most promising samples to analyze, she says.

Fernàndez-Remolar and Knoll thinly sliced the Rio Tinto rocks to see the microbial structures. Although future rovers could be equipped with more powerful micro-imagers, they still wouldn't be able to peer inside the rocks. The next generation rover is expected to pulverize samples and to analyze the dust, a process that would obliterate the shape of anything that happened to be preserved.

Even missions designed to bring samples of Martian rocks back to Earth are unlikely to be able to select and ship back enough rocks to make detection of fossils probable, says Stoker. "The missions most likely to find definitive evidence of fossil life on Mars will be those conducted by human crews," she claims.