Wolf Rayat stars are some of the most massive and dangerous stars in the Universe, living out the final days before they explode as supernovae. And astronomers have found two of them orbiting one another at distances varying as close as the Sun is to Mars and as far as the Sun to Neptune. One star is 20 times the mass of the Sun, and the other 50 times the mass of the Sun, and they only take 7.9 years to complete their orbital cycle.
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On its recent Titan flyby, Cassini took a series of detailed images of the Eastern edge of the bright Xanadu region. Cassini had only viewed this region with its synthetic aperture radar on a previous flyby, so this was an opportunity to image the area in infrared. In the centre of the image is a bright "island" completely surrounded by a dark "sea" of material. There is also an 80 km-wide (50 mile) impact crater, which has also filled up with this dark material.
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If you think current telescopes are powerful, just you wait. A new class of observatories are in the works that could sport mirrors as large as 100 metres (328 feet) across, and have 40 times the observing power of the Hubble Space Telescope. A new study developed by a commission of European astronomers proposes that instruments this large could be built for approximately 1 billion Euros and take 10-15 years to construct.
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"Sakurai's Object" is a white dwarf star that surprised astronomers when if flared brightly in 1996. They originally thought it was a common nova explosion, but further observations have uncovered that the star has actually reignited its stellar furnace. Computer simulations predicted that it could be possible for leftover hydrogen to sink into the star and drive a new flash of hydrogen fusion. If the simulation is correct, the star will stay bright until around the year 2200.
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A vast looping structure 20 light-years across has been discovered near the heart of the Milky Way. The loop was found near a star forming region of our galaxy in the X-ray spectrum using the European Space Agency's XMM-Newton space telescope. Very high energy particles, usually only seen coming from pulsars or supernovae remnants, are streaming out of the object, so it could be working as a kind of natural particle accelerator.
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Astronomers have discovered more than 150 planets orbiting distant stars, but only indirectly. Now an international team of researchers think they might have the first direct photograph of a planet orbiting another star. The image is of GQ Lupi, a young star located 400-500 light-years away. A dimmer object, potentially a planet, is located to the right of the star separated by 100 astronomical units (2.5 times the distance of the Sun to Pluto). Unfortunately, the astronomers haven't been able to determine the mass of the object, so they can't rule out that it might be a brown dwarf.
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Scientists from the European Space Agency have strongly recommended that that the next scientific mission to Mars should be a rover. The ESA's EXOMARS rover would have a similar design to NASA's Spirit and Opportunity, but it would have a suite of instruments designed to search for evidence of past or present life. The rover would arrive on Mars in 2013 to begin the search for life. The ESA is also planning a mission for 2016 that would return samples from the Martian surface to Earth.
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Gamma ray busts are the most powerful known explosions in the Universe, so if one went off in our galactic back yard, it could be bad for life on Earth. Researchers working with NASA think that a massive extinction hundreds of millions of years ago could have been started by such an explosion. If a GRB went off only 6,000 light-years away, it would strip away much of the Earth's ozone layer, and expose all surface life to deadly levels of ultraviolet radiation from the Sun.
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When you look at a galaxy, you can only see a fraction of its total mass. The rest is made up of mysterious dark matter, which only interacts through its gravity. This dark matter usually extends as a giant halo around the galaxy, extending much further than the visible stars. But researchers in the UK have found ancient fossil galaxies concentrating dark matter at their centres. These fossil galaxies are the result of an entire galaxy cluster collapsing into a single enormous galaxy. Why the dark matter is concentrated is still a mystery.
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In preparation for its return to flight, the space shuttle Discovery made the long slow journey atop its Crawler Transporter out to the launch pad yesterday. A small crack was discovered in the fuel tank insulation, but engineers didn't feel it was enough of a risk to delay Discovery from moving out to the launch pad. If everything goes well, Discovery will lift off on May 15, but a final report from the Columbia Accident Investigation Board could demand additional changes that would push the launch back.
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The Chandra X-Ray Observatory has detected distant galaxies going through a period of tremendous star formation, at the same time the supermassive black holes at their centres are packing on material. These extremely luminous galaxies (and their black holes) went on this growth spurt more than 10 billion years ago, and they could be getting ready to turn into quasars - distant galaxies that contain the largest and most active black holes in the Universe.
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NASA has given Spirit and Opportunity up to another 18 months to continue rolling around the surface of Mars in search of evidence of past water. The rovers have already completed their primary 3-month missions, and then an additional 11 months of extensions. Both rovers are still in surprisingly good shape, and are approaching targets that would have initially been considered out of reach. Opportunity set a new driving record on March 20, completing 220 meters (722 feet) in a single day's drive.
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When the planetoid Sedna was discovered last year, astronomers noticed that it had a very slow rotation speed, only turning once every 20 days. One way to slow the rotation of a planet is through the interaction of a moon, but detailed observations of Sedna with Hubble failed to turn up any evidence of a satellite. New observations by astronomers with the Harvard-Smithsonian Center for Astrophysics have revised Sedna's rotation speed to once every 10 hours, which is what you'd expect for an object this size. No moon is necessary.
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NASA's Cassini spacecraft made another close pass of Titan, Saturn's largest moon, on March 31, delivering new images and data from this mysterious moon. Although Titan's northern hemisphere had been imaged by Cassini's radar instrument on a previous flyby, this time it was able to take optical and infrared pictures that pierced through the moon's thick methane atmosphere. This composite image of four photographs was taken when Cassini was approximately 130,000 km (81,000 miles) away from Titan.
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Astronomers have used the Spitzer and Hubble space telescopes to see some of the first stars that formed in the most distant galaxies ever seen. These stars, located in galaxies in the Fornax cluster, are about 13 billion light-years away - they emitted this light only a few hundred million years after the Big Bang. Even though they didn't have much time to form, these galaxies already look quite old, which means that star formation must have got going very early on.
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Since its launch late last year, NASA's Swift space telescope has already spotted 24 gamma-ray bursts - the most powerful known explosions in the Universe. Now Swift has measured the distance to two of these explosions which occurred on March 18/19; both are more than 9 billion light-years away. Swift should become even more accurate in the next few months as more of its instruments are enabled.
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When he developed his General Theory of Relativity, Einstein predicted that the motion of large masses should create ripples in spacetime called gravity waves. Now 100 years after his theory, a precise instrument is being prepared that should be able to find out if he was right or not. A joint ESA/NASA mission called LISA (Laser Interferometric Space Antenna) will launch in 2012. It will consist of three spacecraft flying 5 million km apart, which measure their distances from each other precisely. LISA should be able to detect black holes and neutron stars as well as echos from the Big Bang.
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Starburst galaxies get their name from the enormous amount of star formation going on inside them; on average, they create 50 times as many stars as regular galaxies like our own Milky Way in vast regions of furious star formation. Astronomers from the UK think these regions could also be the home to black holes. The team looked at Hubble images of these star-forming regions, and compared them to X-ray images of the same locations and found the telltale signs for both star formation and black holes.
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The chances of finding life somewhere else in the Universe depends on how many planets are capable of supporting life. Well, according to new calculations by astronomers at Open University, as many as half of all star systems could contain habitable planets. The team created mathematical models of known exoplanetary systems, and then added Earth-sized planets into the mix. They found that in half of all planetary systems they simulated, the gravity of the gas giants won't catastrophically affect the orbits of these smaller planets, giving life a chance to evolve.
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Greetings, fellow SkyWatchers! This week's dark sky will give us the opportunity to wander into the galactic realm as we study the M81 and M82 and many other bright galaxy collections. April 8 provides an opportunity to witness a hybrid solar eclipse - with many portions of it viewable to the southern United States. We'll visit with the "Owl" and don the "Sombrero", so get out those binoculars and telescopes...
Because here's what's up!
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NASA's Cassini spacecraft took this image of Pandora, orbiting just beyond Saturn's F ring. Pandora is only 84 km (52 miles) across. This image was taken on February 18, 2005, when the spacecraft was 1.2 million km (746,000 miles) away from Pandora. Cassini will make a much closer to approach to Pandora on September 5, when it comes within 31,600 km of the small moon.
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A NASA-funded researcher has created an image of the Earth as it would look if you had gamma ray detectors for eyes. Gamma rays are the most energetic radiation known in the Universe - billions to trillions more energetic than visible light - and people usually associate it with extreme environments like black holes and supernovae. The radiation in this image was captured over the course of seven years by the Compton Observatory, which orbited the Earth from 1991 to 2000.
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NASA's Cassini spacecraft took this picture of Mimas, Saturn's "Death Star" moon on February 18, 2005 at a distance of 938,000 km (583,000 miles). The image was taken using Cassini's ultraviolet filter, which helps to reveal better contrast of the moon's craters than would be possible in visible light. Mimas' large crater Herschel dominates the upper right of the picture.
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Have you ever replaced the light bulb inside your fridge? Take a look next time. It draws about 25 watts of power. Now imagine this bulb on a spacecraft somewhere around Neptune and it's flashing madly away, trying to send a signal back to Earth. Somehow we need to see these flashes. Sound impossible? Well almost, but Douglas Mudgway in his book Big Dish describes the system, in particular the antenna sites, that was put into place to capture just this type of signal.
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Launched from "Cape Kennedy" just 13 months of one another in 1972/73, Pioneer 10 and 11 are still up there though no longer kicking. But well before last phone home (in 2003 and 1995 respectively), the notes each pair played had changed pitch unexpectedly - they were slowly losing speed. Could the Pioneering Pair have been feeling a bit in the "dark" (as in "dark matter" or "dark energy")? Were they having a "Solar Quadrupole" moment? Could n-dimensional "branes" be behind it? Or has "back-gravity" from behind the Sun played a role? Before things get too exotic, maybe there's a simpler explanation.
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A powerful Proton K rocket blasted off from the Baikonur Cosmodrome in Kazakhstan Tuesday night, carrying a Russian Express-AM2 communications satellite. It lifted off at 2231 GMT (5:31 pm EST), and placed its payload into a geosynchronous transfer orbit a few hours later. The Express-AM2 satellite will provide broadcast television and other communication services for Russia and Southeast Asia.
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It's for people. That's why we explore space, push ourselves to the next level, and continually strive forward. Machines may be the advance guard but they can never capture our hearts and souls. Perhaps people may forget this adage, but, under Ron Howard's direction, the cast and members of "Apollo 13" put on a memorable drama and remind us that people are number one.
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After a long life, most sun-like stars grow into red giants once they've depleted most of their hydrogen fuel. The relatively small region around the star which is just at the right temperature to support liquid water will extend as the red giant expands. This means that previously frozen planets (like Mars) could thaw out and life might have a second chance to happen in a solar system. There are currently 150 red giant stars within 100 light-years of the Earth, and many of these could be a place to search for life in addition to main-sequence stars similar to our own Sun.
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Galaxies are built up over time through a series of collisions with other galaxies. Each time this happens, clouds of gas and dust collapse and become regions of furious star formation. The European Space Agency's ISO infrared space telescope has shown the early stage of a collision between two galaxies (NGC 4038/4039) 60 million light-years away. The overlapping region between the galaxies is very rich in molecular hydrogen in an excited state. The shock waves are just starting to collapse the gas, and should lead to starbirth in the next few million years.
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The European Space Agency's Mars Express spacecraft took this image of the Medusa Fossae Region on the Red Planet. This is an unusual region of Mars that was probably built up by a series of volcanic flows or rains of ash, and then partially eroded by water. Finally, a large asteroid, several kilometres across, struck the region and "splashed" ejecta onto the plateau.
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Some current models of galaxy formation predict that large spirals such as the Milky Way and Andromeda Galaxy should have more satellite galaxies than are currently known to astronomers. Many of these galaxies should be much smaller than those already discovered. Astronomers reviewing data from the automated Sloan Digital Sky Survey (SDSS) have now added a tenth satellite to the Milky Way's dwarf spheroidal galaxy contingent and this one is a real lightweight.
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Greetings, fellow SkyWatchers! This week will bring some excitement as asteroid Pallas flies through the galaxy fields of Virgo and the Moon occults Antares for Hawaii. We'll focus on exploring some strange and unusual nebulae, and learn why it's "aurora season". The week will end with the several meteor streams and the opposition of Jupiter. So grab those binoculars, set up the telescope and hope for clear skies, because...
Here's what's up!
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The astronauts on board the International Space Station spent a few hours walking around in space today. They installed new antennas to help guide the new European "Jules Verne" cargo ship when it launches next year. They also released a tiny Russian satellite by hand - flight engineer Salizhan Sharipov "threw" it off the station at a velocity of about 1 metre/second. The whole spacewalk finished ahead of schedule, and the two men returned inside after spending about 4.5 hours in space.
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A team of European astronomers has found some unusual objects in the central part of our galaxy which are emitting very high-energy gamma rays. What's strange, though, is these objects are invisible in the optical and X-ray spectra. So what they are is a complete mystery. Not only that, but these objects are also quite large; possibly on the order of several light years across. The observations were done using the High Energy Stereoscopic System (H.E.S.S.) telescopes in Namibia.
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This is a satellite photograph of two huge sandy regions in the Fezzan region of Southwest Libya, near the border of Algeria. A persistent high-pressure system keeps this region of Libya completely dry for years at a time. The photograph was taken by the European Space Agency's Envisat satellite using its Medium Resolution Imaging Spectrometer (MERIS).
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When a 10-km (6-mile), dinosaur-killing asteroid struck the Earth 65 million years ago, it released so much energy that it vaporized rock, which then fell like rain around the world. Scientists now think that these droplets of rock, called spherules, condensed out of a cloud of water vapour that surrounded the Earth shortly after the impact. They were able to trace the composition of the spherules back to the original Chicxulub impact crater, demonstrating that the material came from the Earth, and not the asteroid itself.
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NASA announced on Wednesday their first Centennial Prizes, which will reward the development of new technologies for space exploration. The first is the Tether Challenge, where various teams will compete to see who can built the strongest cable material. In the Beam Challenge, teams will build power transmitters that send energy wirelessly to a robot climber - the winner's robot will lift the most weight to the top of a 50-metre cable. The winner of each prize will be awarded $50,000. Follow on challenges are planned for next year, and will award even higher prizes.
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Officials announced on Tuesday that Greece has formally become the 16th country to join the European Space Agency. The country's Hellenic National Space Committee had been participating with the ESA since the 1990s, exchanging information, fellowship awards and access to databases and laboratories, but it only applied for official inclusion in 2003.
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A new astronomical survey is in the works to help uncover the source of the mysterious dark energy which is accelerating the expansion of the Universe. Set to begin in 2009, the Dark Energy Survey will collect data on approximately 300 million galaxies, reaching back two-thirds of the history of the Universe. A 520-megapixel camera will be installed onto the 4-metre Blanco Telescope at the Cerro Tololo Inter-American Observatory in Chile, allowing astronomers to survey the sky 10 times faster than they could before.
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NASA's Spitzer telescope has detected the light from distant planets for the first time. Until now, extrasolar planets have only been discovered indirectly, by the effect of their gravity on their parent star. Astronomers first detected two planets using indirect methods, and then used Spitzer to perform followup observation with its infrared instruments. They detected the difference in star brightness when the planet was in front and behind the star, and were able to calculate how much of this light was supplied by the planet.
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The Milky Way has several star clusters; collections of stars pulling each other into a tight group. But now astronomers have located a super star cluster, containing hundreds of thousands of stars in a region only 6 light-years across. It's called Westerlund 1, and nobody discovered it before now because it's hidden behind thick clouds of dust. Astronomers used several of European Southern Observatory's infrared telescopes to peer through the dust and see the super cluster's true size.
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Greetings, fellow SkyWatchers! With a full Moon this week, it will be hard to find things to do under the stars - or will it? We begin the week with morning observations of Comet LINEAR and move on towards meteor showers, variable and double stars and a Jupiter/Moon conjunction with an occultation for southern Australia. We'll explore lunar features and rudimentary astrophotography as well as just have some fun. So take out those telescopes and binoculars, because...
Here's what's up!
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All Quasar's have black holes for hearts - but that doesn't mean they are unfriendly. In fact, 9 billion light year distant QSO2237+0305 may like us so much that it wants to make sure we see it even though it is actually hidden by a much nearer spiral galaxy. What can we learn from QSO2237+0305? For one, the cross that bears Einstein's name can tell us a lot about space-time curvature. For another, it can teach us invaluable lessons about how to see things otherwise hidden from view. If you have access to the scope and the skies, you too can see what the whole spectacle is all about.
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As part of its new Vision for Space Exploration, NASA will first be returning to the Moon before sending human explorers to Mars. Although Mars is a much more Earth like environment, with an atmosphere, similar length of day and large amounts of water, the Moon is going to be the agency's first target. Why? Mainly, it's much closer, so astronauts can practice working in an extreme environment close to home before making the much more difficult and riskier journey to Mars.
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Officials from the European Space Agency and Indian Space Research Organisation have approved on a cooperative project to send a spacecraft to the Moon. ISRO will launch Chandrayaan-1 in 2007/2008 to analyze the Moon to help understand its origin and evolution. Europe will provide three scientific instruments identical to ones on SMART-1, which is currently orbiting the Moon.
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NASA's Cassini spacecraft was recently in a lucky position in space earlier this month to watch its own private lunar eclipse, as one of Saturn's moons (Mimas) passed in front of another (Janus). Cassini's camera was rolling the whole time, and the spacecraft captured 37 images that have been stitched together into a movie of the event. Some large terrain is visible on Mimas, including its gigantic crater (the one that makes it look like the Death Star from Star Wars).
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