Hubble camera has stopped working

A camera that has taken some of the most spectacular pictures of the universe has packed up, Nasa revealed tonight. The Advanced Camera for Surveys on the Hubble space telescope stopped working on Saturday. Engineers believe that the power supply to its electronics failed. The loss is a blow to astronomers because the camera has recorded amazing images of targets from planets to distant gas clouds and galaxies. They include the photograph of the Orion Nebula shown here. The camera had been operating on a back-up system since its primary electronics package malfunctioned in June last year. Nasa will try to get the main electronics system operating again. However, if they fail then the camera could be out of action until a shuttle servicing mission flies to the orbiting telescope in September next year. Hubble switched into a safe mode following the latest failure but was put back online on Sunday. Observations will resume this week using other Hubble instruments including a second imager, called the Wide Field Planetary Camera 2. A list of back-up observing programmes will be carried out to replace those that would have been performed with the ACS. The camera was installed during a previous shuttle servicing mission in March 2002. Hubble is jointly operated by Nasa and the European Space Agency. ©PAUL SUTHERLAND, SpaceStories.com • For more space reading, plus other bargains, check out the Skymania store!

Dig deep to find the Martians

Spaceprobes to Mars need to dig deep if they are to find alien life, UK experts said today. Any Martian microbes are hiding several feet down to escape deadly radiation from space and the Sun, their report reveals. Many scientists believe that living cells exist on the Red Planet, possibly in a form of suspended animation. Drills on current Mars missions can find signs suggesting that there was once life on Mars, but any alien remains they find will be dead. Scientists at University College London say this is because microbes could not survive the radiation levels for long enough any closer to the surface of Mars than a few metres deep. That is beyond the reach of even state-of-the-art drills. Unlike Earth, Mars does not have a magnetic field, thick atmosphere or oceans of water to shield the planet against deadly radiation levels. The UCL scientists' study, published in the journal Geophysical Research Letters, maps out the cosmic radiation levels at various depths on Mars. It takes into account different surface conditions on Mars and shows that the best place to look for living cells is within the ice at Elysium, a newly discovered frozen sea near the Martian equator. Lead author of the UCL study, Lewis Dartnell, said: "Finding hints that life once existed - proteins, DNA fragments or fossils - would be a major discovery in itself. But the Holy Grail for astrobiologists is finding a living cell that we can warm up, feed nutrients and reawaken for studying." He added: "It just isn't plausible that dormant life is still surviving in the near-subsurface of Mars - within the first couple of metres below the surface - in the face of the ionizing radiation field. "Finding life on Mars depends on liquid water surfacing on Mars, but the last time liquid water was widespread on Mars was billions of years ago. Even the hardiest cells we know of could not possibly survive the cosmic radiation levels near the surface of Mars for that long." Survival times near the surface reach only a few million years. This means that the chance of finding life with the current probes is slim. Scientists will need to dig deeper and target very specific, hard-to-reach areas such as recent craters or areas where water has recently surfaced. The team found that the best places to look for living cells on Mars would be within the ice at Elysium because the frozen sea is relatively recent. It is believed to have surfaced in the last five million years and so has been exposed to radiation for a relatively short amount of time. Ice is also relatively easy to drill into. Other ideal sites include recent craters, because their surface material has been exposed to less radiation, and the gullies recently discovered in the sides of craters which are thought to have flowed with water in the last five years. The UCL team carried out tests to study the effects of radiation on different types of surface - dry rock, water ice and rock with layers of permafrost. The picture is a Nasa artist's impression of a future deep-drilling lander. ©PAUL SUTHERLAND, SpaceStories.com • For more space reading, plus other bargains, check out the Skymania store!

Mars' oceans 'are locked underground'

Most of Mars' ancient oceans could still be hidden below its dry and dusty surface, according to European space scientists. Observations by an orbiting spaceprobe show that vast seas may have disappeared underground along with most of its atmosphere. The findings, following two years of study by Europe's Mars Express mission, come just weeks after Nasa reported signs of liquid water flowing on the surface. Scientists believe that billions of years ago, the Red Planet was a warm and wet, blue world like Earth. Surface features such as channels and gullies show that there were seas half a mile deep. But some sort of catastrophic climate change turned Mars into a dry and icy desert. It was thought that most of the Martian carbon dioxide atmosphere and water were blown away into space by winds from the Sun. However, observations from Mars Express - the mothership that carried Britain's ill-fated Beagle 2 lander - show that the planet is losing only 20 grams (0.7 oz) of air a second into space. Calculating backwards, this suggests that only a small fraction of Mars' air and a few centimetres of water have been lost that way. Space scientist Stas Barabash, of Sweden, tells the journal Science that Mars's ancient seas may be stored in a vast underground reservoir. The Mars Express image shown here is of what resembles pack ice - part of a dust-covered frozen sea near the Martian equator, according to UK Mars scientist John Murray, of the Open University. He believes that microbes could be lying dormant beneath the ice. Photo: ESA. ©PAUL SUTHERLAND, SpaceStories.com • For more space reading, plus other bargains, check out the Skymania store!

Star blinks reveal secrets of Titan

Two stars far across the galaxy have helped scientists discover secrets of a world in our own solar system. Saturn's biggest moon Titan - which is thought to resemble a primitive Earth - was observed as it passed in front of the distant stars. The rare celestial alignments allowed astronomers to study winds in Titan's thick atmosphere as starlight shone through it. They discovered that Titan has its own fast moving jet stream blowing at 450mph more than 125 miles above its surface. Bruno Sicardy, of Paris Observatory, organised expeditions to record the star blinks, called occultations, just seven and a half hours apart from different parts of the globe in 2003. His results, which appear in the Journal of Geophysical Research, are confirmed by results from Europe's Hygens probe which parachuted to Titan's surface in Jannuary 2005. Sicardy said: "Titan's atmosphere acts like a lens, so at the very middle of the occultation, a bright flash occurs. It is like the light falling through a glass of water and making bright patterns on the table." Analysing the shape of the flash of starlight showed that Titan's atmosphere was flattened at the north pole because it was tilted away from the Sun and therefore cooler. Titan, which is 3,200 miles wide, has been found to have mountains plus lakes and rivers of liquid methane. Scientists believe it resembles Earth as it was four billion years ago and so could be a new cradle for life. Picture: This ESA artist's impression shows the "light curve" produced by a star passing behind Titan, Saturn’s biggest moon. ©PAUL SUTHERLAND, SpaceStories.com • For more space reading, plus other bargains, check out the Skymania store!

McNaught takes time out for comet

The astronomer who discovered the most spectacular comet in over 40 years took a holiday to get away from all the fuss. Robert McNaught, whose brilliant find is now dominating sunset skies Down Under, escaped the limelight to observe it himself in peace. Comet McNaught is so prominent that emergency services in New Zealand received calls from people worried that a plane was falling out of the sky. Crowds have been gathering at lookout points across the southern hemisphere to catch a view of the brightest comet since Ikeya-Seki in 1965. Modest McNaught, who grew up in Prestwick, Ayrshire, said he tries to ignore the fact that the comet has made his name famous around the world. He told Skymania News: "I try to ignore it. I'm a comet fan and willing to travel to the best locations to see them at their best. Regardless of the name, I'd have been excited. "The media attention can be a problem in taking up time that would otherwise be used to plan - and enjoy - my own observations. For this reason I took a few days' vacation around the time the comet was at its brightest to simply have fun observing it!" McNaught, 50, said the comet became so bright that he managed to spot it from a plane at 40,000ft in daylight. Later he photographed the comet's broad, curtain-like tail against a dark sky when the brilliant head had already set below the horizon. McNaught, who works at Siding Spring Observatory, New South Wales, monitoring the sky for hazardous asteroids, recalls the moment last August when he discovered the comet. It then appeared as a faint smudge on a photographic image. He said: "At discovery it was a typical faint object, but within a couple of days it was clear that it would get very close to the Sun. I started to get excited then." The photo of the comet was taken by David Litchfield, from Perth, Western Australia, on January 20. ©PAUL SUTHERLAND, SpaceStories.com • For more space reading, plus other bargains, check out the Skymania store!

Pluto probe closes in on Jupiter

The fastest spacecraft ever sent into the solar system has almost reached Jupiter, just a year after it was launched. Nasa's £400 million New Horizons probe has begun taking photos and other measurements of the giant planet and its four biggest moons. It will use Jupiter's own gravity like a slingshot to catapult it on towards its eventual target, distant Pluto. The flypast will boost its speed by an additional 9,000mph to more than 52,000mph. Even so, it has so far to travel - around four billion miles - that it will not reach Pluto, on the edge of the solar system, until July 2015. Mission control will use the flyby to test New Horizons' systems and put seven science instruments through their paces. It will make more than 700 observations of Jupiter's stormy atmosphere, its faint ring system and its four largest moons. The spacecraft also will take the first-ever trip down Jupiter's "tail" - a wide stream of charged particles, called the magnetosphere, that extends tens of millions of miles beyond the planet. Closest approach to Jupiter occurs on February 28. Chief scientist Alan Stern, of the Southwest Research Institute, Boulder, Colorado, said: "Our highest priority is to get the spacecraft safely through the gravity assist and on its way to Pluto." He added: "We also have an incredible opportunity to conduct a real-world encounter stress test and to collect some valuable science data." The artist's impression of the New Horizons probe approaching Jupiter was produced by Dan Durda of the Southwest Research Institute. ©PAUL SUTHERLAND, SpaceStories.com • For more space reading, plus other bargains, check out the Skymania store!

Galactic calm may reveal black hole

A rare moment of calm could give astronomers their first glimpse of a hungry black hole gorging on stars at the centre of our galaxy. Scientists have long believed that the giant supermassive black hole dominates the middle of the Milky Way. But the "glare" from other energetic objects in the area has blocked their view. Now a space telescope has managed to observe galactic central point on a rare occasion when several of the noisiest sources had faded into temporary silence. Astronomers say the moment of calm is giving them the chance to probe for even fainter objects than usual and may allow them to see material streaming into the black hole. The European Space Agency's observatory Integral, which looks at the heavens with ganmma-ray eyes, has been peering through clouds of dust to study our galaxy's central bulge. The region, in the constellation of Sagittarius, is one of the most dynamic in the galaxy and thought to be home to a gigantic black hole called Sagittarius A*. Integral has been watching the area for nearly two years and has discovered several new sources of high-energy radiation near the galactic centre. They have mainly been X-ray binary stars - double stars where a normal star is in orbit around a star that has collapsed into a super-dense white dwarf, neutron star or even a black hole. As gas is stripped away from the normal star by its violent companion, it is heated to over a million degrees C, causing it to send out high-energy X-rays and gamma rays. By chance, around ten of the noisy sources all fell quiet at around the same time, allowing better observations of the centre to be carried out. Chief ESA scientist Erik Kuulkers rules out the possibility that a mysterious external force calmed the objects at the same time. He said: "All the sources are variable and it was just by accident or sheer luck that they had turned off during that observation." The astronomers are now sifting through observations collected during the period of calm to see if the giant black hole reveals itself. Picture: An Integral image of the galaxy's centre. ©PAUL SUTHERLAND, SpaceStories.com • For more space reading, plus other bargains, check out the Skymania store!

New star in the Southern Cross

One of the most famous stars in the sky has a secret companion, astronomers have discovered. The bright star, called Beta Crucis, is one of four forming the Southern Cross that features on five national flags. Researchers stumbled across a second star orbiting Beta when they examined observations of it from a space telescope. The team from Swarthmore College, Philadelphia, wanted to study X-rays from the star being detected by the Chandra satellite. They were astonished to find a second source of X-rays from the same direction. David Cohen, asssociate professor of astronomy, said: “We were interested in how the highly supersonic stellar winds of hot, luminous stars produce X-rays. We were surprised to see two strong X-ray sources where we had expected to see only one.” Beta is the star on the left in the Southern Cross which features on the flags of Australia, Brazil, New Zealand, Papua New Guinea and Samoa. A paper describing the discovery is to be published in the Monthly Notices of the Royal Astronomical Society. ©PAUL SUTHERLAND, SpaceStories.com • For more space reading, plus other bargains, check out the Skymania store!

Record-breaking star is found

Astronomers have discovered the biggest and brightest known star in the heavens. The star, labelled LBV 1806-20, is between 150 and 200 times the size of the Sun and 40 million times brighter. Professor Stephen Eikenberry, of the University of Florida, observed the star using the historic 200-inch telescope on Mount Palomar, California. Folllow-up studies were made using data collected by the Blanco 4-meter telescope, shown in the picture, at the National Optical Astronomy Observatory's Cerro Tololo Inter-American Observatory in Chile. The star lies 45,000 light-year away from Earth, towards the centre of the Milky Way in the constellation of Sagittarius. It could be up to seven times brighter than the previous record-breaking candidate, called the Pistol Star, which lies in the same constellation. LBV 1806-20 got its label because it was identified as a "Luminous Blue Variable star" - a relatively rare, massive and short-lived star, estimated to be less than two million years old. The Sun, by contrast, is five billion years old, halfway through its life. LBVs have "short and troubled lives," says Professor Eikenberry, because "the more mass you have, the more nuclear fuel you have, the faster you burn it up. They start blowing themselves to bits." He has submitted a paper on his discovery to the Astrophysical Journal. ©PAUL SUTHERLAND, SpaceStories.com • For more space reading, plus other bargains, check out the Skymania store!

Earth 'ripped out Moon's heart'

The Earth literally broke the Moon's heart when the two worlds once got too close, says a scientist. Both worlds formed from the same cloud of gas and dust in the early days of the solar system. But the blob forming the moon was ripped apart in a close encounter with Earth. Iron from the centre of the Moon was torn out and scattered over our own planet, Peter Noerdlinger, of Saint Mary's University in Halifax, Canada, told astronomers in Seattle. His new proposal explains why the Earth has an iron core at its centre but its natural satellite does not. Previous theories have suggested that the Moon formed from material ejected when Earth was struck by another planet. But Noerdlinger said such a collision would have to be "implausibly gentle" because otherwise it would have messed up the Earth's orbit. His calculations of the Moon's brush with Earth show that once the iron from its core was pulled out, the remains collected to form the Moon as it is today. He claims there is evidence that the Earth acquired a veneer of iron after it formed, New Scientist magazine reports. ©PAUL SUTHERLAND, SpaceStories.com • For more space reading, plus other bargains, check out the Skymania store!

Astronomers find cannibal star

British astronomers have discovered a new type of cannibal star that has gobbled up its companion. They identified a twin-star system where one star has stripped so much material away from the other that it can no longer shine. Researchers at Sheffield University discovered the hungry star using a high-speed camera called Ultracam which they had developed. They bolted it onto the UK's giant William Herschel Telescope on La Palma, pictured, in the Canary Islands, to monitor a star 750 light-years away in the constellation of Sextans. Dr Stuart Littlefair was able to detect the star's dead victim as it zipped in front of it. By timing this eclipse, his team showed that this companion is a brown dwarf, only a twentieth the size of the Sun. Such cannibal star systems had long been predicted but never found. Around half the stars in the sky are systems of two or more stars in orbit around each other. In some of these binary systems, the two stars are so close to each other that they almost touch. Astronomers have long believed that this would mean some stars losing so much material that they would lose the ability to sustain nuclear fusion and burn. The problem was they could not find the stellar cannibals. Dr Littlefair told me: "The star we found didn't start off as a brown dwarf. It was originally shining as a star about half the size of the Sun" He said: "It was beginning to look as if these systems either didn't exist or were too difficult to find using current telescopes. Finding this system was important because their existence had been predicted for so long but, try as we might, we couldn't find any of these cannibalised stars". He added: "This research not only confirms a long-standing theory but it also shows that we can actually find and study these objects, which will hopefully allow astronomers to learn a lot more about how stars die." ©PAUL SUTHERLAND, SpaceStories.com • For more space reading, plus other bargains, check out the Skymania store!

Bright comet puts on great show

This weekend offers the last opportunity from the UK to view a spectacular teatime comet that is the brightest for over 30 years. Comet McNaught is sporting a two million mile-long tail and is an impressive sight in the southwest at around 4.45 to 5.15pm, after the sun has set. It was reaching its closest point to the sun today, about 15.8 million miles from it, less than half the distance of innermost planet Mercury. After the weekend, it heads out of UK skies and will be visible only from the southern hemisphere. It will be closest to Earth on January 15 when it will lie 76 million miles away. Comet McNaught is the brightest since 1975 and three times brighter than Hale-Bopp in 1997. It was discovered from Australia by Scotsman Robert McNaught, originally of Prestwick, Ayrshire. Robin Scagell, of the UK's Society for Popular Astronomy, said yesterday: "This is a classic textbook comet with a beautiful bright tail. But you'll have to get your skates on to see it! "Make sure you don't have any buildings or tall trees blocking your view because you'll need a clear south-western horizon to spot it low in the sky. You'll see it about a hand's width to the right of brilliant Venus. "If the sky is clear it should be a fine sight, easy to spot with the unaided eye and even more impressive through binoculars." A crystal clear sunset across the UK gave stargazers a dazzling view of the brightest comet on Wednesday night. Robin, who photographed it from near his home at Flackwell Heath, Bucks, said: The comet was a lovely sight, and easily visible." Computer programmer Dave Pearson spotted the comet with his son Ben, four, from their home village of Billingborough, Lincs. He said: "I was absolutely gobsmacked. It looked like a proper comet. "The core was very bright and it had quite a long tail too - a really fantastic sight. My son, who isn't quite five yet, was very excited to see his first comet." Official measurements confirmed the comet to be the brightest since Comet West hung in the morning sky in 1975. The comet's tail is about two million miles long. But the body of the comet itself is a chunk of ice from the outer solar system, probably about the size of the Isle of Wight. The accompanying image of the comet was taken by me from Richmond, South West London, in hazy skies on January 11. Many better ones can be found at Spaceweather.com. ©PAUL SUTHERLAND, SpaceStories.com • For more space reading, plus other bargains, check out the Skymania store!

Hubble's Pillars of Creation toppled

Hubble's most famous picture target - the so-called Pillars of Creation - may have been toppled by a massive cosmic blast, say astronomers. The three finger-like features in the Eagle Nebula were destroyed by a shock wave from a nearby supernova, 6,000 years ago, they believe. But because the gas cloud lies 7,000 light years away from the Earth, it will be another 1,000 years before the destruction of the pillars becomes visible from Earth. Their fate was revealed by another space telescope, Spitzer, using its infrared heat-seaking eye. Hubble's classic photo, seen below, was taken in 1995. A new, striking image from Spitzer shows the intact dust pillars below a giant red cloud of hot dust thought to have been scorched by the blast of a star that exploded. When the mighty pillars do crumble, gas and dust will be blown away, exposing newborn stars that were forming inside. A new generation of stars might also spring up from the dusty wreckage. Astronomers have long predicted that a supernova blast wave would mean the end for the iconic pillars. The region is littered with 20 or so stars ripe for exploding, so it was only a matter of time, they reasoned, before one would blow up. The explosion that caused the destructive dust cloud may already have been seen from Earth between 1,000 and 2,000 years ago. ©PAUL SUTHERLAND, SpaceStories.com • For more space reading, plus other bargains, check out the Skymania store!

Ooops! We've killed the Martians

Space probes have already met the Martians - and killed them by drowning or frying them, some scientists believe. The wipeout, 30 years ago, was an accident because the two Viking landers were looking for a type of life different to the Martians' actual make-up. Professor Dirk Schulze-Makuch, of Washington State University, has taken a fresh look at data recorded by Nasa's Viking probes in 1976. He told the American Astronomical Society, in Seattle, that he believes it indicates the presence of living alien microbes formed from a mix of water and hydrogen peroxide - hair bleach. The robot Vikings carried our experiments on Mars that would have killed these Martians. One poured water on the soil and would have drowned them. Another heated the soil so much that it would have baked them alive. Professor Schulze-Makuch said scientists working on the Viking projects were not looking for organisms that rely on hydrogen peroxide, because no one was aware that such organisms could exist. Since then, discoveries of so-called extremophiles on Earth have shown that organisms can thrive in extreme conditions such as radioactivesites and volcanic vents. The professor and colleague Dr Joop Houtkooper, of Giessen, Germany, argue that hydrogen peroxide-containing organisms can explain nearly all the results observed in the Viking experiments. “If the hypothesis is true, it would mean that we killed the Martian microbes during our first extraterrestrial contact, due to ignorance,” said Professor Schulze-Makuch. Nasa's next mission to the surface of Mars is due for launch in August this year. Called Phoenix, it willl land near the martian north pole and dig into the soil for evidence of life. Nasa has revealed plans for two new unmanned missions to Mars. One called MAVEN - Mars Atmosphere and Volatile Evolution mission - will be a weather satellite for Mars, investigating its climate and measuring changes in the planet's upper atmosphere. The other, tagged The Great Escape mission, will also examine how the atmosphere works but will look for indicators of life, such as methane gas, as well. Nasa is spending two million dollars on initial nine-month preparations for each of the missions. Nasa also agreed to fund a scientist to join Europe's own mission to land on the Red Planet. ExoMars is due for launch in 2013, carrying a rover to drive around on Mars and dig for life. Alian Wang will use instruments on the mission to study the make-up of Martian soil and look for signs of biological activity. Picture: The Nasa images shows Viking 2 on the surface of Mars. ©PAUL SUTHERLAND, SpaceStories.com • For more space reading, plus other bargains, check out the Skymania store!

Astronomers map spread of dark matter

The Hubble space telescope has mapped out the invisible universe for the first time in 3D - and found that it is lumpy. Astronomers detected so-called "dark matter" that is five times more abundant than the material you can see, formed of atoms, that makes up stars and galaxies. Their results show that galaxies and clusters of galaxies accumulate in the densest concentrations of dark matter. The invisible material is spread in filaments like a spider's web across the universe. Hubble's map shows the web stretching halfway back to the beginning of the universe and becoming increasingly lumpy as it collapses under the force of gravity. Scientists at the California Institute of Technology built the dark matter map by measuring the shapes of half a million distant galaxies. They detected how the light from the galaxies was distorted and deflected by the invisible material lying in its path before it hit Hubble's orbiting eye. Astronomers say the challenge was like trying to map a city from aerial photos that showed only streetlights. They created the map using Hubble's largest survey yet of the universe - the Cosmic Evolution Survey, or COSMOS - which covers a region of sky nine times the area of the Earth's moon. Results were combined with observations from some of the biggest telescopes on Earth. British-born researcher Richard Massey, now at CalTech, said: "It's reassuring how well our map confirms the standard theories for structure formation." He described dark matter as the "scaffolding" inside which stars and galaxies have been assembled. Experts say that mapping dark matter's distribution in space and time is fundamental to understanding how galaxies grew and clustered over billions of years. The results appeared yesterday this week in the online version of the journal Nature. ©PAUL SUTHERLAND, SpaceStories.com • For more space reading, plus other bargains, check out the Skymania store!

Google search will find asteroids

Google is taking searching to a whole new level by joining the hunt for killer asteroids. The internet giant is to help operate a new giant telescope that will scan the heavens for space rocks that threaten potential disaster. The telescope, with a mirror "eye on the sky" more than 27ft wide (8.4 meters), will be built on a 2,682 metre high mountaintop in northern Chile by a team of 19 US universities and research laboratories. It will be fitted with a three billion pixel digital camera capable of detecting so-called near-Earth asteroids as small as 100 yards wide. The Large Synoptic Survey Telescope is expected to start scanning the sky in 2013, producing more than 30 thousand gigabytes of data every night. Google will contribute by using its data management technology to handle that massive amount of information. The telescope, which can view a chunk of sky seven times the width of the Full Moon at any one time, is also expected to spot exploding supernovae and new dwarf planets, or Kuiper Belt objects, beyond Pluto. As if that were not enough, it will also check billions of galaxies for the effects of those invisible forces dark matter and dark energy. Google said they were keen to help generate a new and dynamic view of the night sky for the public. Their Vice-President of Engineering, William Coughran, said "Google's mission is to take the world's information and make it universally accessible and useful. The data from LSST will be an important part of the world's information, and by being involved in the project we hope to make it easier for that data to become accessible and useful." The telescope's project manager Donald Sweeney said: "The LSST will be the world's most powerful survey telescope. "Even though the universe is very old, exciting things happen every second. The LSST will be able to find these events hundreds of times better than today's other big telescopes. Google will help us organize and present the seemingly overwhelming volumes of data collected." The image is an LSST impression of the telescope on the El Peñón peak of Cerro Pachón. ©PAUL SUTHERLAND, SpaceStories.com • For more space reading, plus other bargains, check out the Skymania store!

Cassini confirms liquid lakes on Titan

Scientists have discovered a new Lake District deep in the solar system, they revealed today. Liquid pools cover the surface of Titan, Saturn's biggest moon, marking it as the most Earth-like world in the solar system. The discovery of more than 75 lakes - which contain methane instead of water - follows the finding of rivers, a snow-capped mountain range and coastlines on 3,200-mile wide Titan. The lakes range in size from just under two miles to 45 miles across, the science journal Nature reports. They were spotted by an instrument aboard Nasa's Cassini spaceprobe which bounced radar signals through Titans's hazy orange atmosphere. Scientists are excited because the evidence suggests that Titan resembles Earth as it was four billion years ago and so could be a new cradle for life. They believe that when the sun swells up, swallowing the Earth, conditions for life could be ideal on a warmed-up Titan. Professor John Zarnecki, of the Open University, who landed a probe called Huygens on Titan in January 2005, told me: "We believe the chemistry is there for life to form. It just needs heat and warmth to kick-start the process. In four billion years time, when the sun swells into a red giant, it could be paradise on Titan." The European probe, which had been carried the 2.5 billion miles to the Saturn system aboard Cassini, detected organic chemicals that are the building blocks of life, including nitrogen and methane, as it parachuted to a soft, slushy landing on a rock-strewn landscape. The Nasa picture is made up of two radar images from Cassini, taken on July 21, 2006, of Titan's northern hemisphere, showing the lakes. ©PAUL SUTHERLAND, SpaceStories.com • For more space reading, plus other bargains, check out the Skymania store!

Tricky asteroid threat for Hallowe'en

Hallowe'en is supposed to be scary, but for those of a nervous disposition, October 31, 2041, will carry an extra thrill - the tiny risk of an asteroid impact. Astronomers are keeping their eye on a space rock, labelled 2006 XG1, which has a one-in-48,000 chance of hitting Earth on that date. Those are pretty good odds for a miss. But if it did hit, XG1 would blast a crater ten miles wide and half a mile deep. The explosion, equal to 1,700 megatons of TNT, could wipe out a city and cause devastation across hundreds of miles. Apollo astronaut Rusty Schweickart told me that, although the risk appears small, XG1 is further proof that the asteroid threat should be taken seriously and preventative action taken. What is likely, according to latest Nasa calculations, is that the asteroid will whizz past just 3,000 miles away - less than the distance from London to New York. That is a hair's breadth, compared to the moon's distance of a quarter of a million miles. XG1 is thought to be half to two-thirds of a mile across, so even at that distance you would not be able to make out its shape with the naked eye and it would appear as just a fast-moving dot of light. XG1 was discovered on September 20 by a robotic camera in Arizona that is working to scour the sky for asteroids called Near Earth Objects as part of the Catalina Sky Survey. It was logged as a potential problem that should be monitored. But subsequent observations have not seen the threat disappear. The asteroid orbits the sun in a little under four years. The threat posed by XG1 is higher than that from another asteroid called Apophis, 400-yards wide and weighing 25 million tons, which will fly closer than TV satellites on Friday 13th of April, 2029. Experts say that if Apophis passes through a several hundred-yard wide "keyhole" on that brush with Earth, it will collide with us in 2036. Nasa and the European Space Agency are both examining plans for Armageddon-style missions to change the course of threatening asteroids so that they miss us. But Rusty, who flew on the Apollo 9 mission in 1969, told me: "All asteroids (124 as of today) with a non-zero probability of Earth impact are good reason that we should prepare to protect Earth from impacts. "And given that we have knowledge today of only around two per cent of the total population of NEOs which can cause destruction on the surface if they impact, it is important that the subject be taken seriously. "First, get the early warning system in shape, i.e. properly funded and programmed. Second, test/demonstrate the "existing" deflection capability (existing technology can protect against a subset of the overall threat) to build public confidence and learn by doing... and, get the advanced technology under development to assure a "full" capability. "Third, get in place an agreed upon international decision-making capability re NEO deflection so that timely and coordinated decisions can be made." He added: "The biggest issue in all of this, in the US, is that Nasa is not assigned the responsibility to provide mitigation (i.e. deflection) against NEO impacts. Nor is anyone else. Therefore there is no budget allocation to pay for anyone to even think about this work, let alone fly a demonstration mission or start new technology. "Until this assignment is made (to Nasa or someone) this work will not be done. This is the cosmic equivalent to knowing that the New Orleans levies are too weak... but no one has the responsibility. And unlike New Orleans/Katrina, we're not talking about reducing the damage, we're talking about preventing the disaster from happening in the first place." ©PAUL SUTHERLAND, SpaceStories.com • For more space reading, plus other bargains, check out the Skymania store!