Here's how to remember planets

At the risk of developing a Pluto fixation, it does seem to me that part of the fall-out of the International Astronomical Union's ruling is that we need a new mnemonic to help beginners remember the order of the planets. Of course, their order has not actually changed. It is simply that Pluto has been dropped. But that is enough to render the old aides memoires useless. My Very Educated Mother Just Served Us Nine Pizzas seems to have been a favourite for remembering Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. I've already heard My Very Educated Mother Just Served Us Noodles suggested as a replacement. But that seems a bit of a cop-out to me. So in tribute to those masters of the universe the IAU, who created the new order, I have my own suggestion: Many Very Eccentric Men Just Sacked Unwanted Nonentity. (And apologies to any women who were in on the vote). Of course, I just had to stick it on a T-shirt. ©PAUL SUTHERLAND, SpaceStories.com

Atlantis in about-turn surprise

Nasa took the space shuttle Atlantis off the launch pad today - then changed their minds and sent her back. The craft was a mile into the ten-hour journey to the Vehicle Assembly Building when the surprising about-turn occurred. She was being carried on a giant crawler transporter because of fears of a storm bearing down on the Kennedy Space Center from Cuba. But when forecasts of Tropical Storm Ernesto's intensity were re-evaluated, space chiefs decided to weather it out. The storm is due to pass through tomorrow night. Nasa are keen to get Atlantis into space before the current launch window closes on September 7. Atlantis was due to lift off on Sunday but that was cancelled after the launch tower was struck by lightning. ©PAUL SUTHERLAND, SpaceStories.com

Star's violent beautiful death

Tattered remains of a star that blew itself to pieces were revealed in a dramatic new photo from the Hubble space Telescope released today. Nasa's orbiting observatory pictured in astonishing detail the aftermath of a violent supernova explosion that happened 340 years ago. A mosaic built from 18 separate images shows the supernova's ejected shell as a broken ring of wispy gas and debris moving at speeds of up to 30 million mph. Huge swirls glow with the heat from the stellar suicide's shockwave. The supernova, in the northern constellation of Cassiopeia, is called Cas A. Astronomers believe the blast happened when the star, which lies ten thousand light-years from the Earth, collapsed under the weight of its own gravity. Debris ejected in the supernova blast is moving so fast that it could get from the Earth to the Moon in just 30 seconds. The suprnova images were taken with Hubble's Advanced Camera for Surveys. ©PAUL SUTHERLAND, SpaceStories.com

Mysterious clouds on Mars

The highest clouds ever spotted above a planet's surface have been detected by a European spaceprobe orbiting Mars. Scientists say the fleeting clouds, which are probably made of carbon dioxide, lie between 50 and 60 miles up (approximately 80-100km). They were discovered when an instrument aboard the European Space Agency's Mars Express observed stars dimming noticeably before they disappeared behind the red planet. Any Martians would see the clouds best after nightfall when they shine with the reflected light from the sun below the horizon, said mission scientist Franck Montmessin, of France. They resemble rare and mysterious noctilucent clouds seen in summer from the UK which also glow in the northern sky around midnight. The height of the clouds over Mars means they are unlikely to be made of water, the scientists report in the journal Icarus. Data from SPICAM, a spectrometer observing the atmosphere in the ultraviolet and infrared, shows that they form around microscopic grains of dust blown high into the atmosphere. The results have important implications for future missions sent to land on Mars because they suggest the upper layers of the Martian atmosphere can be denser previously thought. The clouds in the accompanying picture were taken by Nasa's Pathfinder rover in August 1997 and show clouds in the Martian eastern sky before sunrise. They may be of the same type as those detected by Mars Express. ©PAUL SUTHERLAND, SpaceStories.com

Lightning strike delays Atlantis

Space shuttle Atlantis's lift-off was postponed today until Tuesday at the earliest after its launch pad was hit by the biggest lightning strike ever recorded by Nasa. A camera caught the massive bolt as it hit the tower at Florida's Kennedy Space Centre during an intense thunderstorm, sending 100,000 amps of current through the conductor system. Nasa later discovered an irregularity in the shuttle's electrical circuit. An explosive bolt that separates one of the hydrogen venting lead to Atlantis was also left charred by the strike. They also want to check if the solid booster rockets were damaged by the storm. Nasa launch director Mike Leinbach said he believed the lightning strike, on Friday, was the strongest ever to strike pad 39B. Atlantis was not itself hit. But lift-off, which had been due today, was immediately postponed by at least 24 hours so that engineers could carry out a thorough safety check. Atlantis is sister ship to Discovery which returned to space last month carrying British astronaut Piers Sellers after the fleet had been grounded for a year. The crew of mission STS-115 consist of Commander Brent Jett, Chris Ferguson, Heidemarie Stefanyshyn-Piper, Joseph Tanner, Daniel Burbank and Canadian Steve MacLean. Nasa are keen to launch regularly in future to complete building of the International Space Station before the shuttle fleet is retired in 2010. During the mission, a major new truss and a second set of solar arrays to generate power from sunlight will be added to the orbiting outpost. ©PAUL SUTHERLAND, SpaceStories.com

Planets . . . if the cap fits, wear it

Pluto's demotion has certainly caused a flurry of interest throughout the news media. And the IAU's new definition of a planet is proving highly controversial, especially in the United States. In the light of the deliberations by our masters of the universe, I couldn't resist coming up with my own rather more simple definition for planets. And if you happen to think it offers a comment, too, on the ruling from Prague, then that is entirely a matter for you. It simply reads: Planets - Great balls up in space. Thanks to CafePress you can proudly display it yourselves on a T-shirt, mug, bumper sticker . . . or a cap, of course! You can see the designs here at the store. ©PAUL SUTHERLAND, SpaceStories.com

Pluto gets the boot after all

The solar system shrank a little today after the world's top astronomers voted to drop Pluto as a planet. The International Astronomical Union, meeting in Prague, created a scientific definition of a planet for the first time. The decision means that there are now eight planets known to orbit the Sun. They are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. A plan to create a new class of world called either plutons or plutonian objects was dropped. Instead, Pluto is demoted and joins its moon Charon and newly discovered 2003 UB313, nicknamed Xena, as what will be called dwarf planets. So too will Ceres, the largest of the asteroids that circle the sun between Mars and Jupiter. The IAU's resolution declares that a planet is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit. In other words, that it is large enough to have swept its region clear of smaller bodies. Robin Scagell, of the UK's Society for Popular Astronomy commented after the vote: "All the illustrations of the solar system will have to be redrawn. But Pluto was always the odd one out, and this decision clears up the 76 years of doubt since Pluto was discovered." Photo: IAU/Lars Holm Nielsen ©PAUL SUTHERLAND, SpaceStories.com

Dark matter is found at last

Space scientists have found proof of the existence of a major component of the universe - even though it can never be seen. They discovered conclusive evidence that the cosmos is filled with something called dark matter by watching the most dramatic event witnessed since the Big Bang. Observations of a tremendous collision between two large clusters of galaxies revealed dark matter and normal visible matter being wrenched apart. The Hubble telescope, Nasa's X-ray observatory in space, Chandra, and some of the biggest observatories on Earth were used to study a colection of galaxies called the Bullet Cluster, or 1E0657-56. They found a 100 million-degree hot gas cloud was bound up with the galaxies - something that would be impossible without the gravitational pull of an even greater amount of dark matter in the region. Astronomers believe that visible material such as stars, gas clouds and galaxies make up less than a 20th of the universe. They suspected the presence of a mysterious invisible component by studying the gravitational pull of galaxies on each other which are much stronger than predicted by Einstein. Dark matter is thought to be responsible and could form as much as 22 per cent of the universe. The remaining 74 per cent is believed to be something even more peculiar - dark energy. Discovery team leader Doug Clowe, of the University of Arizona, said: "A universe that's dominated by dark stuff seems preposterous, so we wanted to test whether there were any basic flaws in our thinking. These results are direct proof that dark matter exists." ©PAUL SUTHERLAND, SpaceStories.com

Meteor storm 'due next year'

A comet which last passed us nearly a century ago could produce a spectacular storm of meteors over Earth next year. Experts say our planet will sweep through a vast trail of debris left by Kiess's Comet, which only makes an appearance from the depths of the solar system about every 2,000 years. For around two hours, bright fireballs could rain down over us according to US astronomers Peter Jenniskens and Jereme Vaubaillon. The date for the predicted shower is September 1 next year with the peak happening during nighttime over the western USA. Scientists are excited because the meteors will be made up of fragments of the comet's original crust found in the Oort Cloud on the fringes of the solar system. They are more than 4.5 billion years old and older than the rocks on Earth. The comet was discovered from the Lick Observatory, California, in 1911. The scientists say it last crossed the Earth's orbit in 82 BC when Julius Caesar was a junior officer and Rome was ruled by the dictator Lucius Cornelius Sulla. Jenniskens, of the SETI Institute, and Vaubaillon, of Caltech, call the oncoming storm the Alpha Aurigids because the meteors will appear to stream in from the direction of the brightest star Capella in the constellation of Auriga, the Charioteer. They told delegates at the International Astronomical Union conference in Prague: "A two-hour outburst of Alpha Aurigids will occur. The typical meteor will be so bright that the Moon won't dim much of the display." They added: "What makes this shower so special is the opportunity to see bits and pieces of the comet's original crust. Long-period comets have just recently returned from cold storage in the Oort cloud and are still covered by a crust that resulted from 4.5 billion years of exposure to cosmic rays. "When the comet returns to the inner solar system, that crust is crumbled and creates peculiar meteors." ©PAUL SUTHERLAND, SpaceStories.com

Solar system gets bigger again

Astronomers have made another major discovery in the depths of the solar system - a billion, billion new worlds orbiting the sun. The distant space rocks are all less than a hundred metres wide and form a vast band of debris beyond Neptune. They are far too small to be seen with any telescope at that distance. But scientists have so far managed to spot 58 of them indirectly using an ingenious technique. From that small sample, they deduce that there must be around a quadrillion of the rocks - called Trans-Neptunian Objects - in orbit. The scientists discovered the rocks by examining observations of a star called Scorpius X-1 from a Nasa satellite that observes with X-ray eyes. The star is the brightest such object outside the solar system. Records from the Rossi X-ray Timing Explorer, pictured here, showed occasional, almost instantaneous fades in the star's light as one of the rocks passed in front of it. The dips are a similar effect to an eclipse of the sun and are properly called occultations. They lasted between two and seven milliseconds. Scorpius X-1 is thought to include a neutron star. The investigating astronomers, from Taiwan, ruled out any effect in the star's own neighbourhood for the fades. Team leader Hsiang-Kuang Chang tells the journal Nature: "We conclude that occultation by objects in the Solar System is the most plausible explanation to these dip events." Fortunately for astronomers, the space rocks are too small to be planets and so don't need names. ©PAUL SUTHERLAND, SpaceStories.com

Faintest stars among the jewels

The Hubble telescope has opened a cosmic jewel box to reveal a collection of stars sparkling like diamonds. Its stunning new photograph of a globular cluster called NGC 6397 is dazzling in its spendour. But it has also captured, between the brilliant jewels, what are believed to be the faintest stars ever seen in such a cluster. The light from these dim stars is as faint as the glow of a birthday cake candle on the Moon as viewed from Earth. NGC 6397 is a city of hundreds of thousands of stars and lies in the costellation of Ara. The stars look dazzling but their starlight has taken 8,500 years to cross space and reach the Earth. Hubble's picture was taken by a team led by Harvey Richer of the University of British Columbia, Vancouver, using the space telescope's Advanced Camera for Surveys. Their results were announced to an international meeting of astronomers in Prague and will appear in today's edition of the journal Science. Richer said: "There are no fainter such stars waiting to be discovered. Any less massive ones faded early in the cluster's history and by now are too faint to be observed." Globular clusters formed early in the 14 billion-year-old universe. Despite its great distance, NGC 6397 is actually one of the closest such cluster to Earth. Viewing the whole range of stars in the cluster will help astronomers to understand its age, origin and how it evolved. ©PAUL SUTHERLAND, SpaceStories.com

Jets form spiders from Mars

Powerful geysers erupt on Mars, sending jets of gas and dust hundreds of feet into the air, scientists have discovered. The dramatic event occurs every two years around the Red Planet's frozen south pole as spring sunlight warms the ice. Nasa experts say the powerful 100mph jets are caused by the release of carbon dioxide gas from beneath the martian icecap. There are thousands of the geysers every spring. Their existence solves the riddle of mysterious dark spots and spidery markings photographed by Nasa's orbiting Mars Odyssey spaceprobe. The dark features, between 50 and 150ft wide, appear for three or four months then vanish as winter forms a new layer of ice. US scientists examined images taken with a special thermal camera on Odyssey called Themis that reveals the temperature of Mars, the journal Nature reports. Phil Christensen, of Arizona State University, described the dramatic scene on Mars for any astronaut visitor. He said: "All around you, roaring jets of CO2 gas are throwing sand and dust a couple hundred feet into the air. You'd also feel vibration through your spacesuit boots. The ice slab you're standing on would be levitated above the ground by the pressure of gas at the base of the ice." He added: "Originally, scientists thought the spots were patches of warm, bare ground exposed as the ice disappeared. But observations made with Themis told us the spots were nearly as cold as the CO2 ice, which is at -198° Fahrenheit. A few places remained spot-free for more than 100 days. Then they developed a large number in a week." The scientists say the dark spots are the heavist debris that falls back from the eruptions. They also observed fan markings where lighter dust had spread in the wind. A further puzzle was the spider-shaped markings. These are explained as dust-filled grooves carved beneath the ice by the high-speed gas rushing towards the geyser vents. (Image Credit: Arizona State University/Ron Miller) ©PAUL SUTHERLAND, SpaceStories.com

Actually we've got 53 planets

The man who discovered the IAU's recommended new 12th planet reckons the organisation can't count. Dr Mike Brown says their proposed definition of a planet means there are now at least 53 of the worlds, not nine or twelve. Brown, whose own find, 2003 UB313, has been nicknamed Xena, told me that 44 recently discovered icy worlds beyond Neptune fit the IAU's new criteria. There are likely to be hundreds more. As I revealed earlier, Brown, of the California Institute of Technology, agreed with me that it was "crazy" to exclude the Moon from being a planet. He added: "Also strange is that they seem to have a hard time counting. I come up with 53 planets." You can read Brown's interesting take on it all here. He says: "Astronomers have needed a good scientific definition of the word 'planet' for many years now and this one works well for scientists. It doesn't, however, work terribly well for the rest of the world. "The solution is the one that should have happened long ago: a divorce of the scientific term 'planet' for the cultural term 'planet.' No one expects school children to name 53 planets. If I were a schoolteacher, I would teach perhaps 10 and then say "scientists consider many more things to be planets too" and use that opportunity to talk about how much more there is in the solar system." The image of new planet Xena, revealing it has a moon, nicknamed Gabrielle, was taken at the Keck Observatory, Hawaii. ©PAUL SUTHERLAND, SpaceStories.com

Pluto saved - why not the Moon?

Top astronomers are saving Pluto's pride by allowing it to remain a planet. They will demote the distant world by reclassifying it as a new object called a pluton. But they have also changed the definition of what a planet is so that it includes the plutons too. Basically, the International Astronomical Union's new definition requires a planet to be something big enough to be round - or roundish - and orbiting a star. As long as it is not another star. That means the sun keeps Pluto as a planet and has three new planets besides, bringing the total number up to 12. Two are also plutons, including 2003 UB313, nicknamed Xena. And a third is freshly promoted asteroid Ceres. The other of the new plutons, Charon, is a moon of Pluto. It is less than half the diameter of our own Moon. So does that mean our Moon is a planet too? No. Giant planets Jupiter, Saturn and Neptune all have moons bigger than Charon. Two are bigger then the planet Mercury. But they are not planets either. Why not? The bizarre explanation is that Pluto and Charon do their celestial dance around a point that lies between them in space. The Earth and the Moon orbit each other in a similar way. But the point around which they revolve lies beneath the Earth's surface. If it had been in space, the Moon would have been promoted. The same goes for the moons of the giants. Dr Mike Brown, associate professor at the California Institute of Technology and discoverer of 2003 UB313, told me: "You've hit on just one of the many crazy parts of this definition." The third in the IAU's new list of planets, Ceres, is the largest of the asteroids. Its 950km diameter is a fraction of the Moon's 3,476km. The IAU say Ceres may be referred to as a "dwarf planet" but stress that that will not be an official term. To add to the confusion, the IAU is doing away with their former official term "minor planets" for the asteroids. It will be replaced with the phrase "small solar system bodies". For the record, the IAU's proposed new list of planets, shown in the picture above, is: Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Charon and, er, 2003 UB313. Now try to make a mnemonic out of that! © PAUL SUTHERLAND, SpaceStories.com

Pluto 'to lose planet status'

Pluto faces being evicted from the solar system in a Big Brother-style vote by the world's leading astronomers. Patrick Moore told me he is backing the monumental decision which will see the number of planets cut from nine to eight. A committee of expert scientists is set to give distant Pluto the boot by stripping it of its status as a planet. Instead the celestial vagabond will be downgraded and reclassified as just one of a myriad of icy objects wandering far from the sun. A final decision will be made by space science's governing body, the International Astronomical Union, at a conference in Prague. But TV star Patrick Moore agrees Pluto should be relegated to the lower divisions. He said yesterday: "Pluto isn't a planet - it's as simple as that." Pluto was discovered in 1930, bringing the known number of planets to nine. It was actually named by an English girl, Venetia Burney. But the cat has been put among the pigeons by the recent discovery of other celestial bodies beyond Neptune. They have been labelled Kuiper Belt Objects and are thought to be part of a vast belt of icy debris on the fringes of the solar system. The largest so far found, which has been nicknamed Xena, is 1,500 miles across - 70 miles wider than Pluto. So astronomers are being forced to decide whether to call them planets too or change Pluto's status. Patrick, presenter of BBC TV's long-running show The Sky at Night, said: "Recently, about 15 other objects have been discovered and at least two are bigger than Pluto. There must be stacks more lurking out there. Clyde Tombaugh, who discovered Pluto, was a friend of mine and invited me to write a book about it with him. "It will be sad to see it relegated but it is just a question of scientific sense. Pluto is a Kuiper Belt Object. It means there will only be eight planets - but there is always the chance we will find another real planet out there again one day." The IAU committee that has been charged with defining Pluto's status is led by Professor Iwan Williams, of Queen Mary University of London. They have been tight-lipped about their deliberations but will announce their recommendations on Wednesday. Astronomers will debate the issue on Tuesday next week and take a final vote two days later. © PAUL SUTHERLAND, SpaceStories.com The photo shows Pluto imaged by Hubble in 1995.

Perseid fireworks a 'damp squib'

Tonight is the night when one of the year's great meteor showers puts on its best performance - yes, it is the maximum of the Perseids. So of course, after a long hot summer heatwave, the weather has decided to turn particularly bizarre and produce its own non-meteor shower here in the south east of England. In fact it has been bucketing down all day with squally conditions blowing down from the north. It is good for the garden, everyone says. And in truth the Moon was already going to put its own dampener on events. Just past full, it will drown out many of the meteors even if you are lucky enough to have clear skies in your part of the world. Normally one might expect to see one every two or three minutes at maximum. The shooting stars are produced as the Earth passes through a vast river of dust left by a passing comet called Tempel-Tuttle. They look bright but are usually no bigger than grains of sand, glowing as they vapourise in the upper atmosphere. The good news is that the shower will continue for a week or more yet and although the rates will diminish, the Moon will interfere less and less. © PAUL SUTHERLAND, SpaceStories.com

Time again for summer Mars hoax

By PAUL SUTHERLAND, SpaceStories.com Astronomers are once again having to deny a silly internet scare story that Mars is about to become as big in the sky as the Moon. A hoax email sweeping the world claims that the planet is racing towards the Earth for a close encounter on August 27. It says: "The Red Planet is about to be spectacular. Earth is catching up with Mars for the closest approach between the two planets in recorded history. On August 27, Mars will look as large as the full moon. No one alive today will ever see this again." But Nasa's Dr Tony Phillips says the email is a hoax by someone confused with Mars's bright appearance in the sky in 2003. At that time it did look as large as the Moon - but only if you magnified it by looking through a big telescope. He pointed out: "If Mars did come close enough to rival the Moon, its gravity would alter Earth's orbit and raise terrible tides." Alan MacRobert, a senior editor of Sky & Telescope magazine said: "The Mars chain letter gets revived every August. "I see it as a good thing, not a bad thing. It's an immunization. If you make a fool of yourself by sending it to your friends and family, you'll be less likely to send them the next e-mail chain letter you get, which may not be so harmless." This summer, Mars is actually at its furthest from Earth, on the other side of the sun and hidden in its glare. It looks big in our picture - but then that is a photo by the Hubble telescope taken in 1997! Photo: Nasa

Rescue shuttles must stand by

By PAUL SUTHERLAND, SpaceStories.com Nasa has ordered a rescue shuttle to be on standby for every manned launch until 2010 when the fleet is due to be retired. The move comes despite the latest flight by the Discovery being a big success. For all future shuttle flights to the international space station, space chiefs require a sister ship to be undergoing preparations to fly. It must be able to rescue a crew from orbit within 45 years of an emergency being declared. Nasa has introduced the new policy following the Columbia disaster when a shuttle broke up on re-entry in 2003 killing all seven astronauts. The accident was caused by insulation foam falling from a fuel tank and damaging the shuttle's wing on launch. More debris was seen to fall on launch of the next shuttle last year leading it to be grounded again until last month's successful flight. If a similar incident critically damages the spacecraft in future, Nasa will use the space station as a lifeboat until the rescue shuttle is launched. They have devised a plan to fly the damaged shuttle back to Earth unmanned. The next shuttle, Atlantis, is due to launch on August 27 with a crew of six, pictured above after arriving at Kennedy Space Centre for a dress rehearsal yesterday. Photo: Nasa

Lust in space drives tourism

By PAUL SUTHERLAND, SpaceStories.com Couples will be clamouring to fly into space to enjoy out of this world sex, an expert claims. Pioneering tourists want to make love in weightlessness while the Earth really does move beneath them. Space writer Laura Woodmansee says enthusiasm to join the 100 mile high club will be one of the biggest forces driving the space holiday business. And she claims honeymoons in space will be a reality within ten years. Companies like Sir Richard Branson's Virgin Galactic, see picture, aim to begin the first passenger flights to the fringe of space within a couple of years. They have already sold more than 200 tickets at $200,000 each. But within a few years orbiting hotels will allow those with even deeper pockets to spend extended holidays in space. Mum-of-one Laura, who has written a book, Sex In Space, is married to a rocket scientist and gives public talks as an official ambassador for Nasa in California. In a possibly unfortunate choice of words, she says: "Sex in space is the ‘killer application’ that will transform space tourism into a mega business. Making love with a view of the Earth below may be the ultimate aphrodisiac for space buffs. The sex in space revolution is about to begin! "Many have wondered what it might be like to make love in space. The passionate couples who book flights to the very first space hotel will be more than excited to try zero-g sex. Some people believe that space sex will be a frustrating experience and that lovers will give up. No way! Weightless couples will find a way to get together. "The bottom line is that sex in space will probably take some practice and hard work at first. Since people are very creative, I have no doubt that it will make for a wonderful otherworldly experience." But Laura warns that couple should be careful not to conceive in space as not enough is known about the dangers to mothers or their babies. Foetal development and sperm movement are known to be affected by a lack of gravity and radiation from space could be a serious problem. Laura tells Space.com that Nasa must do more testing on the consequences of sex in space. Until then, she says it is up to spaceflight companies to take their own precautions before sending couples into space.

Explaining Moon's mystery bulge

By PAUL SUTHERLAND, SpaceStories.com Scientists have discovered why the Man in the Moon has a pot belly. They say it formed in the early days of the solar system when the Moon came much closer to the Earth. Planet experts have been puzzled for years by a mysterious fattening in the lunar midriff. It causes a bulge at the equator on the far side of the Moon which is permanently hidden from Earth but has been pictured by astronauts and from spaceprobes. Scientists at the Massachusetts Institute of Technology say the Moon used to travel in a peculiar oval orbit that brought it close to the Earth. Gravitation caused the molten rock inside the Moon to be pulled outwards as it was still solidifying. Today the orbit is roughly circular but the bulge is still there, the journal Science reports. The US team used ancient records of the times of eclipses to calculate the position of our natural satellite throughout history. They say their explanation ties in with the theory that the Moon was created when an object the size of Mars collided with Earth around 4.6 billion years ago.

Bleach snow 'rules out life on Mars'

A Martian dust devil in Gusev Crater pictured by the Spirit rover on March 15, 2005. (Nasa) By PAUL SUTHERLAND, SpaceStories.com Forget Little Green Men. Aliens from Mars are more likely to be Dizzy Bleached Blondes, if new research is anything to go by. Whirlwinds racing across the Red Planet are whipping up clouds of hydrogen peroxide - better known as hairdressers' bleach - which then falls as snow. Nasa research shows that dust devils and bigger storms generate powerful electric charges - lightning that rips apart chemicals in the martian atmosphere. Molecules from water and carbon dioxide then reform as hydrogen peroxide and other toxic chemicals. But in truth, the findings spell bad news for anyone searching for a race of blond Martians. The toxic bleach would destroy any organic molecules before they could come together to form any life, the scientists conclude. The findings are revealed in two Nasa-funded studies reported in the journal Astrobiology. Dr Gregory Delory, of the University of California, said that over the last three billion years, the accumulated peroxide in the surface soil could have built to levels that would kill "life as we know it." Professor Sushil Atreya, of the University of Michigan, says that the level of hydrogen peroxide forming from dust storms on Mars are high enough to blanket the surface with bleach snow. He said: "As a consequence, any nascent life - microorganisms for example - would find it hard to get a foothold on the surface of Mars as the organic material would have been scavenged by the surface oxidants." Nasa say the new findings help solve a 30-year-old riddle posed by the first spacecraft they successfully landed on Mars. Two Viking probes which arrived in 1976 sent back conflicting results from tests carried out after water and nutrients were added to the martian soil. One lander reported no sign of organic matter in the dirt. But the other recorded activity as the nutrients were broken down. Scientists wondered whether they were seeing signs of life in the soil. But they now believe they were fooled by similar effects caused by the hydrogen peroxide.

Can you find specks of stardust?

By PAUL SUTHERLAND, SpaceStories.com Space scientists are calling on home computer users to help find specks of dust from between the stars. They began a search on Tuesday that will be like a cosmic version of finding a needle in a haystack. Anyone with a computer can join in the Stardust@home mission to spot tiny particles of dust collected by a Nasa spaceprobe and brought home to Earth. The project is run by the University of California with support from the Planetary Society. Already nearly 115,000 volunteers have signed up since it was first announced in January. That was the month when the spaceprobe Stardust sent a capsule to land in the Utah desert after a seven-year, 2.88 billion-mile trip into the depths of the solar system. On its journey to visit a comet called Wild 2, the probe ran into as few as 50 grains of interstellar dust - just like a car splatting bugs on its windscreen. The precious particles, produced in supernova explosions as much as ten million years ago, were collected by a "windscreen" of fluffy aerogel, the lightest solid substance made by man. The first of nearly 30 million scans from the 132 tiles of aerogel are now being posted on the internet for volunteers to search to try to find the elusive dust. Each scan covers an area the size of a grain of salt. Stardust@home director Andrew Westphal says the microscopic particles will provide clues to the inner workings of distant stars. He said: "These grains will be so precious that they will be studied for decades." Anyone who finds a confirmed dust speck will get the chance to name it. The project follows the success of a similar challenge callled Seti@home which is harnessing the power of half a million home computers around the world to look for radio signals from aliens. To join the Stardust@home search, visit the website http://stardustathome.ssl.berkeley.edu/ Picture: Nasa