Looking back in time from the Moon

The Moon could become an orbiting observatory, allowing astronomers to peer back in time further than ever before. Nasa experts say that our natural satellite could house a powerful optical telescope with a liquid mirror - yes, you read that right - up to 100 metres wide. It comes after scientists previously made the case for a radio telescope on the Moon's far side where it would be sheltered from interference from transmitters on Earth. A lunar optical telescope with a mirror 20-100 metres across would be able to observe objects 100 to 1,000 times fainter than the James Webb space telescope, the planned successor to Hubble. Plus, of course, there are none of the clouds that can thwart ground-based observers. Instead of having a solid mirror, astronauts would pour liquid onto a spinning disk-shaped mesh. The rotation would cause the liquid to take on a parabolic shape, similar to that in ordinary telescope mirrors. Pete Worden, director of Nasa's Ames Research Centre in California, is co-author of a paper describing the novel telescope in the journal Nature this week. Worden says: "We have shown how the Moon is ideal for using liquid mirror technology to build a telescope much larger than we can affordably build in space. Such telescopes, perhaps 100 metres in diameter, can see back to the early phases of the universe after the Big Bang." The paper's lead author is Ermanno Borra, of Laval University, in Quebec, Canada. Nasa's Institute for Advanced Concepts is supporting his team's research. It could form part of the agency's Vision for Space Exploration, which Britain has been invited to partake in. The idea for a radio telescope on the Moon was explained to Skymania News by Ian Morison, of Britain's famous Jodrell Bank in Cheshire, England. He said: "There is no atmosphere on the Moon and, if you built a telescope on the far side, you could avoid radio interference from Earth and the ionosphere. "It would be a wonderful place to carry out low-frequency observations which we are unable to do at the moment. That would allow us to learn more about the origin of the universe." The picture is a Nasa artist's impression of a moonbase with radio telescope dish. ©PAUL SUTHERLAND, Skymania.com • Skymania welcomes your comments on our stories! For more space reading, check out the Skymania stores in the USA and in the UK. They are powered by Amazon so you can buy with confidence.

Tunguska impact crater 'found at last'

Scientists believe they may finally have found a crater produced by one of the biggest cosmic impacts with Earth in recent history. In 1908, a small comet or meteor exploded over Tunguska, a remote region of Siberia, flattening trees for up to 2,000 square kilometers. The blast is estimated to have been equivalent ten to 15 million tons of TNT. There were a few dramatic eyewitness accounts of a huge fireball and bright glows were seen over Europe and Asia. Despite this, the region was so remote that no expeditions were sent until the late 1920s. However, no traces of the impacting body have ever been found, and investigators concluded that the cosmic missile exploded 5-10 km above the ground. Now an Italian team has examined a 300-metre wide lake just 8 km NNW of the centre of the explosion and have concluded that it probably fills a crater formed in a secondary impact following the initial blast. Due to the remoteness of the region, no one is able to say that the lake was there before the Tunguska Event - it does not feature on any maps. The scientists base their conclusions on the funnel-like form of the lake's bottom plus imaging of sedimentary deposits within it. The team, who publish their findings on the online site of the journal Terra Nova, say the object struck swampy ground covered in permafrost and this affected the size and shape of the crater. They say the bowl-shape matches that of similar impact craters on Earth, and is slightly elliptical. They suggest the impactor was a fragment left from the iniatial blast and was up to ten metres across. They also believe that it struck the Earth at a low velocity and so is likely still to be buried beneath the lake. A much bigger explosion of a comet over North America may have wiped out Stone-Age tribes, mammoths and other creatures nearly 13,000 years ago. You can read the new Tunguska paper in full here. The photo is from an expedition to Tunguska in 1927, and shows trees flattened by the explosion 19 years earlier. Footnote: UK expert Dr Gareth Collins, of Imperial College London, has said he is skeptical about the Italian claims. He told BBC Online: "In my opinion, they certainly haven't provided any conclusive evidence it's an impact structure. "The impact cratering community does not accept structures as craters unless there is evidence of high temperatures and high pressures. That requires evidence of rocks that have been melted or rocks that have been ground up by the impact." ©PAUL SUTHERLAND, Skymania.com • Skymania welcomes your comments on our stories! For more space reading, check out the Skymania stores in the USA and in the UK. They are powered by Amazon so you can buy with confidence.

New evidence for oceans on Mars

Alien-hunters have found fresh evidence that Mars was once covered by vast oceans of liquid water. They have proved that a large plain near the Red Planet's north pole was probably once a martian sea. The now-dry area closely resembles an ocean basin filled with sediment and it has features just like those of a shoreline. But this seaside strip on Mars is not level which previously led scientists to argue against the presence of an ocean on the site. Now astrobiologists funded by NASA have shown that the unevenness can be explained by a shifting of Mars's polar axis. They believe the weight of the ocean itself was enough to move the north pole up to 50 degrees away from where it is today. When the water all disappeared, the paxis shifted back to its current position. Nasa are now likely to pick the spot for future landers. Carl Pilcher, director of the Nasa Astrobiology Institute in California, said: "This work strongly supports the idea that there were large standing bodies of water on the Martian surface. Interpreting this topography as an ancient northern ocean could have a great impact on current and future Mars exploration." Last month, Nasa's Spirit rover accidentally churned up evidence for past water on Mars. Some European scientists believe that the ancient oceans may have disappeared underground. In December, Nasa reported evidence that water still sometimes flows on Mars. The picture of Mars's north pole region was taken from the Mars Odyssey spacecraft. ©PAUL SUTHERLAND, Skymania.com • Skymania welcomes your comments on our stories! For more space reading, check out the Skymania stores in the USA and in the UK. They are powered by Amazon so you can buy with confidence.

Space giant in challenge to Virgin

Move over, Sir Richard Branson! One of the space industry's biggest players is moving into the tourism business. EADS Astrium has announce plans to build a Space Jet that can fly thrill-seekers from any normal airport to the edge of space. The ship - a rival to Virgin Galactic's Spaceship Two - will look like a business jet and carry four paying passengers at a time to a height of 100km (more than 60 miles). A trip will cost each passenger between 150,000 and 200,000 euro for a flight lasting one a half hours including three minutes of weightlessness. The Space Jet is the brainchild of European rocket builders Astrium, who are looking for private investors. British engineers - already working on a European mission to Mars - are expected to be heavily involved in building the tourist ship. A mock-up of the privately funded jet, including a cabin by London-based designer Marc Newson, who created interiors for Qantas, was shown for the first time in Paris last night. It has been designed in secret since the start of 2006. Astrium's spacecraft is much simpler than Virgin Galactic's SpaceShip Two which will have to be carried aloft by an specially built aircraft before separating and flying into space. Virgin will use a specially built spaceport in New Mexico but have said they would like to launch from an RAF runway in Scotland too. The new Space Jet will take off and land conventionally from a standard airport using its jet engines. However, once the craft reaches an altitude of around seven and a half miles, a rocket engine in the tail will ignite and blast it to a height of 60 miles in seconds. Astrium say the pilot will then control the craft using small rocket thrusters enabling passengers to float free and witness spectacular views through several portholes. The open cabin might be a little too public for any more intimate activities, however. After slowing down during descent, the jet engines will restart for a normal aircraft-style landing on a conventional runway. An Astrium insider said: "Our engineers were inspired by Virgin's SpaceShip One, but that will fly from a purpose-built spaceport. We will be able to fly from any standard airport. The sub-orbital experience can be enjoyed by any healthy person. The training is minimal and not physically demanding." He added: "We are proposing the one-stage system as it is considered the safest and most economical to operate." Astrium hope that Virgin might become a customer for the jet. ©PAUL SUTHERLAND, Skymania.com • Skymania welcomes your comments on our stories! For more space reading, check out the Skymania stores in the USA and in the UK. They are powered by Amazon so you can buy with confidence.

Double blast marks death of a giant

An amateur astronomer has made a major discovery by recording the violent death of one of the most massive stars in the universe. An international team, led by astronomers at Queen's University, Belfast, have now identified the suicide star. Japanese amateur astronomer Koichi Itagaki first photographed a star exploding in a faint galaxy called UGC 4904 in 2004. Two years later he recorded a second, even greater explosion in the same spot, 78 million light years away in the constellation of Lynx. The double blast excited professional astronomers because they believe Koichi witnessed the death of one of the "heaviest" stars that can exist. Last month, we reported how a similar supernova had produced the brightest explosion ever witnessed in another galaxy. Professor Stephen Smartt, of Belfast, and colleague Dr Andrea Pastorello heard of Itagaki's photographs and immediately realised the implications of spotting two explosions in the same place in the sky. They began observing the supernova, named SN2006jc, with telescopes on La Palma in the Canary Islands. They also analysed Itagaki's photos and confirmed that one star exploded twice. They say it must have been a so-called Wolf-Rayet star, which are the most massive type known. Dr Pastorello said: "We knew the 2004 explosion could be a giant outburst of very massive star, and we know that only the most massive stars can produce this type of outburst. So the 2006 supernova must have been the death of the same star, possibly a star 50 to 100 times more massive than the Sun." A similar star in our own galaxy, called Eta Carinae, exploded in the 1850s. Astronomers say it could blow itself to pieces at any time, producing one of the brightest explosions ever seen in the sky and becoming visible in daylight. Picture: An artist's impression of the 2006 blast by Frederic Durillon. Courtesy Service d'Astrophysique/CEA. ©PAUL SUTHERLAND, Skymania.com • Skymania welcomes your comments on our stories! For more space reading, check out the Skymania stores in the USA and in the UK. They are powered by Amazon so you can buy with confidence.

Journey to the centre of the Earth

Space scientists are turning their eyes from the skies to begin a journey to the centre of the Earth. Just like in Jules Verne's scifi classic, NASA wants to discover where lies the heart of the mass that makes up our own planet. But forget any ideas of a manned mission, such as in the notorious Hollywood action movie The Core. Instead they will combine a sophisticated form of SatNav with observations of violent galaxies at the edge of the universe. Scientists at NASA's Jet Propulsion Laboratory, in California, say that pinpointing the centre of the Earth is vital to learning about changing sea levels, earthquakes, volcanoes and even ice ages. But finding the so-called centre of mass is difficult because the Earth is wobbling like a jelly due to movements in its crust and climatic changes. These are believed to cause the point to move by a few millimetres every year. Now NASA expert Donald Argus has developed a new technique to locate our centre of mass to within 1 millimeter. His technique uses data from a high-precision network of global positioning system receivers using laser beams to track high-orbiting satellites in the Lageos network. This information is combined with measurements from a network of radio telescopes of our position in space compared to objects deep in the universe called quasars. Finally, more data is used from a French system called Doris - a network of precise satellite tracking instruments. (Doris is short for Doppler Orbit and Radiopositioning Integrated by Satellite.) Dr Argus said: "The past two international estimates of the motion of the Earth system's mass centre, made in 2000 and 2005, differ by 1.8 millimeters (.07 inches) a year. This discrepancy suggests the motion of Earth's mass centre is not as well known as we'd like." Details of the new study appear in the June issue of Geophysical Journal International. The NASA images shows one of the Lageos satellites and an exaggerated relief image of the Earth produced from satellite data. ©PAUL SUTHERLAND, Skymania.com • Skymania welcomes your comments on our stories! For more space reading, check out the Skymania stores in the USA and in the UK. They are powered by Amazon so you can buy with confidence.

Black hole is most distant discovered

Astronomers have discovered the most distant black hole ever found, nearly 13 billion light years away from the Earth. The cosmic cannibal is nearly as old as the universe. It cannot be seen directly because light cannot escape from within. However, scientists spotted the brilliant glow from swirling hot gas and debris being sucked in like water down a plughole. The black hole is inside a highly luminous type of galaxy called a quasar in the constellation of Pisces. The discovery, revealed at a conference in Kingston, Canada, today, was made by an international team of astronomers using the Canada-France-Hawaii telescope on Hawaii. An imaging instrument called MegaCam took snapshots of more than ten million stars and galaxies which the scientists have been sifting through. Astronomers have named the quasar CFHQS J2329-0301. Its immense distance was revealed by its redshift - the amount by which the fingerprints of elements are shifted towrds the red end of the spectrum. Measurement of one such emission line in the quasar's spectrum showed that it has a redshift of 6.43. Dr Chris Willott, of the University of Ottawa, said: "As soon as I saw the spectrum with its booming emission line, I knew this one was a long way away". The black hole powering the quasar is believed to be 500 million times more massive than the Sun. The image of it here, using three filters, shows how red the quasar is compared to stars and galaxies in the field. In March we told how space telescopes had combined to take a snapshot of the sky revealing the presence of 1,000 massive black holes. Photo: Canada-France-Hawaii Telescope Corporation 2006. ©PAUL SUTHERLAND, Skymania.com • Skymania welcomes your comments on our stories! For more space reading, check out the Skymania stores in the USA and in the UK. They are powered by Amazon so you can buy with confidence.

Most massive star known is found

Space scientists have discovered the "heaviest" star yet found in the universe, at 114 times the mass of the Sun. It lies 20,000 light years away in the constellation of Carina. They used the Hubble Space Telescope together with Europe's Very Large Telescope in Chile to "weigh" the monster, dubbed A1. It is the brightest in a cluster of stars called NGC 3603 and has a smaller companion which is another giant, 84 times the mass of the Sun. The two stars are in orbit around each other. News of the discovery was revealed at a conference at Kingston, Canada, today by Professor Anthony Moffat of the University of Montreal. His team weighed the stars by observing how they circled each other. Theory suggests that stars with as much as 150 times the mass of the Sun could inhabit our part of the universe but none has previously been found with more than 83 times its mass. Astronomers talk about stars in terms of mass rather than weight because weight actually depends on the force of gravity. Picture: Universite de Montreal. ©PAUL SUTHERLAND, Skymania.com • Skymania welcomes your comments on our stories! For more space reading, check out the Skymania stores in the USA and in the UK. They are powered by Amazon so you can buy with confidence.

New Saturn image is simply electric

Sometimes an image comes along that takes your breath away. That is not unusual in the amazing world of astronomy but the latest offering from the Cassini probe really stands out. The spacecraft captured a psychedelic image of the dark side of the planet Saturn that would not look out of place in a Pink Floyd light show. It shows the unlit side of Saturn's rings as a brilliant electric blue, while the night side glows red like an ember. The part of Saturn catching sunlight shows in sapphire and mint green. The picture looks unreal and, in truth, the colours are false. But they were fitted to 25 images recorded by Cassini's visual and infrared mapping spectrometer as it built up a mosaic of the ringed planet over 13 hours on February 24. Cassini was looking down on the northern hemisphere of Saturn from a distance of 1.58 million km (a million miles). The red glow represents thermal radiation detected coming from the planet's night side and generated deep beneath the clouds. We have seen this red glow before when the probe caught a fascinating view of a mysterious hexagonal feature at Saturn's north pole. And of course there have been other remarkable pictures returned of the planet and its rings. The Cassini team note that Saturn's northern hemisphere is about twice as bright as the south where fine particles high in the atmosphere block the glow. Photo: Nasa/JPL/University of Arizona. ©PAUL SUTHERLAND, Skymania.com • Skymania welcomes your comments on our stories! For more space reading, check out the Skymania stores in the USA and in the UK. They are powered by Amazon so you can buy with confidence.

Astronomers view a star in close-up

Astronomers have zoomed in to observe detail on the surface of a star like the Sun for the first time. They used a special technique that counters distortion caused by the Earth's atmosphere to focus on nearby Altair. Their data was taken by an artist and used to produce an image showing a star with bright patches on its surface and a bulge caused by its rapid spin - around 60 times faster than the Sun's. Scientists from the University of Michigan made the breakthrough by observing Altair simultaneously with four telescopes on Mount Wilson in California. By detecting the differences between the images observed, the scientists were able to compensate for the effects of our atmosphere. It is not the first time that we have managed to record detail on a star. However, previous targets have been red giants including, famously, Betelgeuse in Orion which was mapped with the UK's William Herschel Telescope on La Palma in 1989. Planets are now also being mapped. Altair is much smaller than the red giants - it is a star that is nearly twice as big as the Sun, hotter and younger and which lies nearly 17 light-years away. It is also one of the brightest stars in the sky, clearly visible in the constellation of Aquila, the Eagle. The telescopes used to study Altair form part of the Center for High Angular Resolution Astronomy (CHARA) operated by Georgia State University on Mount Wilson. John Monnier, lead author of a paper published in Science, said: "This powerful new tool allows us to zoom in on a star that's a million times farther away than the sun. We're testing the theories of how stars work in much more detail than ever before." It might not be long before we are able to detect sunspots on other stars, using a British tool called SuperWASP that has been set up to detect extrasolar planets. Peter Wheatley, a member of the team, from Warwick University, told me last year how this bank of cameras will record the dimming in a star's light when a planet passes in transit across its disk. Peter said that if the planet passed in front of a darker sunspot, the light of the star would brighten once more, revealing its presence. Other planet spotters such as the Corot satellite will be able to show similar detail. The artist's rendition of Altair is by Zina Deretsky, National Science Foundation. ©PAUL SUTHERLAND, Skymania.com • Skymania welcomes your comments on our stories! For more space reading, check out the Skymania stores in the USA and in the UK. They are powered by Amazon so you can buy with confidence.