NASA's Cassini spacecraft is now close enough to Saturn that it's able to resolve the two F-ring-shepherding moons: Prometheus and Pandora. Prometheus is 102 km across, and Pandora is 84 km across, and they interact with Saturn's outermost ring causing clumps and other unusual formations. They have very chaotic orbits, which can change unpredictably when they get close to each other. The moons were originally discovered by Voyager 1 in 1980, and follow-up observations have been made by the Hubble Space Telescope.
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Astronomers will have a powerful new tool for finding extrasolar planets on Friday, when SuperWASP, a new observatory in the Canary Islands, begins operations. SuperWASP has an extremely wide field of view (2000 times larger than a regular telescope) and is able to measure the brightness of hundreds of thousands of stars. It will take enormous surveys of the sky every night, which astronomers will process with a computer. They'll be looking for stars which dim slightly on a regular basis, which would indicate planets passing in front.
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One of the problems of sending humans to Mars will be how to let them explore the surface of the planet without having to carry tons of fuel from Earth. Fortunately, there's a potential source of fuel right on the surface of the planet: magnesium. Researchers from the University of Michigan have performed zero-gravity experiments that demonstrated that magnesium will burn perfectly well in a carbon dioxide atmosphere as long as you use iodine catalyst. It works even better in microgravity - Mars has 1/3rd the gravity of Earth.
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Dutch astronomer Christian Huygens was born on April 14, 1629; exactly 375 years ago. He was an influential astronomer who improved on Galileo's original telescope design by developing new techniques to grind and polish lenses. With his improved telescope, Huygens was able to resolve the rings of Saturn better than anyone at the time, and realize their true shape as rings. He also discovered Titan, Saturn's largest moon. He died in 1695.
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After the announcement of Sedna last month, the solar system's furthest object, astronomers have had the opportunity to look at it better with the Hubble Space Telescope. Sedna's discoverer, Mike Brown from Caltech, was sure it also had a moon, but these new observations didn't turn anything up. This is unusual because Sedna's rotation takes 20 days instead of a few hours like most other asteroids - usually it's a moon that slows down an object's rotation. Based on Hubble's observations, astronomers believe Sedna is no larger than 1,770 km across (3/4 the size of Pluto).
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The European Southern Observatory has released the most detailed images ever taken of the surface of Titan, Saturn's largest moon. The images were taken using a new instrument called the Simultaneous Differential Imager (SDI), which was originally designed to help image extrasolar planets. The images show a number of surface regions with different reflectivity, including several dark areas with very low reflectivity, which could be huge reservoirs of liquid hydrocarbons. Scientists will get a better look when the Huygens probe arrives in early 2005.
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With the announcement that the twin Mars Exploration Rovers have had their missions extended, scientists and engineers have big plans for the robots. The extended mission for Spirit will see the rover make the journey to the distant Columbia Hills. Opportunity will make a similarly long series of drives to reach Endurance Crater and then to some unusual "etched terrain" further to the South. One short term goal will be for the rovers to calibrate the dusty Martian skies by pointing their panoramic cameras up while overhead satellites look down.
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Techniques that helped sequence the human genome over the last decade could help researchers prove, once and for all, if life ever existed on Mars. Researchers from UC Berkeley have sampled the dry, irradiated soil in Chile's Atacama Desert, which could be a similar situation on Mars, and used techniques that study DNA to search for evidence of amino acids. An instrument that uses this technique, called the Mars Organic Analyzer, could be built into future rovers. It was able to detect the presence of life in the Atacama soil - we'll see if it'll work on Mars.
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The latest image released from the Spitzer Space Telescope shows an incredible stellar nursery which is so enshrouded in dust that no visible light escapes it. This region, called DR21, is a nest of giant newborn stars located about 10,000 light-years away in the Cygnus constellation of our Milky Way galaxy. Previous observations in visible and radio wavelengths indicated that something hidden was producing incredibly powerful jets of material, but nothing more was known until now.
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The Moon is definitely not made of cheese, though viewing it can be much more rewarding than nibbling on cheese. Its many unique features with descriptors like rilles, craterlets, and wrinkles give a certain closeness to our nearest satellite. The "Moon Observer's Guide", by Peter Grego defines these, pinpoints where they occur on the Moon's surface and then adds the familial names for easy reference. You might want to bring cheese when viewing the Moon at night but also bring this book as it certainly will guide you.
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The first of two 8.4 metre mirrors has been installed into the Large Binocular Telescope, which will become one of the world's most powerful telescopes. The 16 tonne mirror made the 240 km journey from Tucson, Arizona to the top of Mount Graham. Technicians are now testing the mirror support system hardware and software. Once the second mirror is installed, the combined light-gathering power will make the LBT the equivalent of an 11.8 metre telescope - it should be able to produce images 10 times sharper than the Hubble Space Telescope.
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NASA has extended the mission for its Mars Exploration Rovers, Spirit and Opportunity, after Spirit met the success criteria for its mission. It spent a total of 90 days roaming the surface of Mars, and traveled a total distance of 600 metres. Opportunity will achieve its successful mission on April 26. This extension includes an additional $15 million in funding to keep operating the rovers until September. Even though the mission has been approved until then, the rovers could last much longer on the surface of Mars.
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Scientists from the University of Arizona have developed a handy calculator that you can use to determine your fate in the event of an asteroid impact. This tool takes into account not only the size of the asteroid and its composition, but what it slams into. It calculates the blast, depth of ejecta, and the force of the air blast at a distance from ground zero. Now you can see if you'll be safe from the devastation of an asteroid strike, or if you'll need to hop in your car and drive... far.
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Are there any contigencies currently in place to stop an asteroid from hitting if say one was detected to hit within days, weeks, months, years? - Damien Igoe, Alice Springs, Australia
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Here's a beautiful 1024x768 desktop wallpaper of a series of sapping channels on Mars called Louros Valles. On the right side of the image is the Ius Chasma canyon, which has dark deposits at the bottom that could be related to wind and water erosion (North is to the right in this image). The image was taken by the European Space Agency's Mars Express spacecraft at an altitude of 269 kilometres during its 97th orbit.
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Scientists have known for a long time now that the Earth's magnetic field unexpectedly reverses polarity over long periods of time, but how often this happens was still a mystery. Brad Clement, a geologist funded by the National Science Foundation, has concluded that the reversal seems to happen every 7,000 years, on average. He gathered this data by analyzing deep-ocean sediment cores. One surprise is that the variation seems to alter with latitude - the directional change takes half as long at low-latitude sites as it does at mid- to high-latitude sites.
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NASA's Cassini spacecraft continues its approach to Saturn, and its latest images show incredible detail of two storms in the act of merging. The storms were both at least 1,000 km wide, and they were moving westward across the surface of the planet, relative to its rotation. After about a month of dancing, the storms actually merged on March 19-20, and the new storm now sits almost stationary on the surface of the planet. Saturn is the windiest planet in the Solar System, and the reason for these winds is one of the mysteries that scientists hope to solve with Cassini.
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The Hubble Space Telescope has been focused to peer deep into the heart of nearby galaxy NGC 300, and revealed the stars as individual points of light; even though it's 6.5 million light-years away. Hubble's Advanced Camera for Surveys has resolved the galaxy 10 times better than ground-based telescopes, which can only see the brightest individual stars.
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The book, "Practical Astronomy", by Storm Dunlop, is a wonderful beginner's guide that brings order to the multitude of light sources in the night sky. In easy to understand descriptions and photographs you can learn to identify zodiacal lights, emission nebulae and of course the major constellations. This is an easy to use, easy to carry reference to help plan for and get the most out of your evening's sky watching.
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NASA's Aura satellite - the latest in a series of Earth observing spacecraft - arrived at Vandenberg Air Force Base this week to be prepared for its June launch. Aura has four instruments which will study the chemistry and dynamics of the Earth's atmosphere to provide scientists with data about ozone levels, air quality and climate change. Aura will undergo final tests and then be mated to the top of its Boeing Delta II rocket.
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The Sun is heating up, and in 4 billion years from now it will swell up to become a red giant - Earth and the rest of the inner planets will be destroyed. But the deadly conditions that destroy the Earth will mean warmer temperatures in the outer Solar System, possibly supporting life. The region from Saturn to Pluto will warm up to the point that frozen water will melt on moons and planets. Scientists think the best chances for life will be found on Pluto and its moon Charon as well as Neptune's moon Triton because they're rich in organic chemicals.
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NASA ordered the Genesis spacecraft to close up its particle collectors this week, to prepare its sample-return capsule to enter the Earth's atmosphere. Over the last three years, Genesis has been collecting particles blown by the Sun on a special array made from exotic materials. This material should give scientists detailed information about the composition of the Sun. Genesis will release its capsule on September 8, 2004, and helicopter pilots will snag it in mid-air with giant hooks.
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After 15 years of observation, over the course of more than 1,000 nights, a European team of astronomers has collected the most thorough survey of our local stellar neighborhood. The team performed an analysis of more than 14,000 stars to calculate their distance, age, chemical analysis, velocity and orbit around the Milky Way. Each star was measured 4 times over the course of this period. It turns out that the motion of stars through the Milky Way is much more chaotic and turbulent than previously thought.
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Most of the asteroid sky surveys have been carried out in the Northern Hemisphere, but astronomers from the University of Arizona have taken the hunt down under. They're using a refurbished telescope at the Australian National University's Siding Spring Observatory. The new survey is funded by NASA's Near Earth Asteroid Survey, that hopes to locate 90% of the spacerocks larger than 1 kilometre, which have the potential to cause severe devastation if they strike the Earth.
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On March 22, 2004, the ESA/NASA SOHO solar observatory spacecraft observed its 750th comet since its launch in late 1995. SOHO has a special instrument that blocks out the glare of the Sun, and allows it to see comets that graze the Sun. Amateur astronomers from around the world analyze the photographs taken by SOHO, which are published on the Internet - more than 75% of the discoveries have been made by amateurs. This one was discovered by Sebastian H?nig from Germany.
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The Chandra X-Ray Observatory captured a rare event in January when Saturn's moon, Titan, passed in front of the Crab Nebula. The large moon was illuminated by the X-rays from the nebula, so it cast a shadow. This allowed astronomers to measure its atmosphere in the X-ray spectrum to be about 880 kilometres thick. This might be the first transit of Titan over the Crab Nebula since it was formed from a supernova explosion in 1054.
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Since it was awarded a contract to study the feasibility of return samples of Mars back Earth, EADS Space has come up with two different directions. The first is to launch the sample ascent vehicle from the surface of Mars and dock with the return vehicle in space. In the second design, the ascent vehicle would reach orbit and then eject the samples for the return vehicle to "catch". How the samples are returned to Earth will make a big difference on the mission's cost, mass and complexity.
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SpaceDev announced on Thursday that it has won a $43 million contract to build micro satellites for the Missile Defense Agency (MDA). The four-phase, five-year contract will see SpaceDev build a micro satellite distributed sensing experiment (three to six microsats), and an option for a laser communications experiment. SpaceDev launched its first and only satellite, CHIPSat, just over a year ago.
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An international team of astronomers have mapped a sizable region of space around the Andromeda Galaxy (M31) and have found the wreckage of many galaxies, torn apart by its massive gravity. One stream of stars has been found stretching back 50,000 to a satellite galaxy which is in the process of being consumed. They also found 14 globular star clusters floating far from Andromeda's centre; the remnants of destroyed galaxies. By studying these galactic fossils, astronomers can better understand the evolution of Andromeda.
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Radio astronomers have successfully measured an object that surrounds the supermassive black hole at the heart of our Milky Way galaxy. The centre of our galaxy lies 26,000 light-years from Earth, but it's normally obscured by gas and dust, so visible light telescopes can't see it. By focusing on the object, called Sagittarius A, with high radio wavelengths, the astronomers were determine that its size is as about the same as the orbit of the Earth around the Sun. The supermassive black hole at the centre is likely the size of the orbit of Mercury, but it contains 4 million solar masses.
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NASA's Spirit Rover has found a rock that seems to have been acted on by water in the past. The rock is called "Mazatzal", and lies partially buried near the rim of the Crater Bonneville; its light-toned appearance caught the eye of NASA scientists. Spirit used its rock abrasion tool to grind under the surface, and found a darker interior with a bright stripe that cut across both layers. This seems to indicate a fracture that water flowed through. More data about the rock is being transferred back to Earth while Spirit drives to Columbia Hills, located 2.3 kilometres away.
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The Gravity Probe B spacecraft, which is designed to test two predictions of Einstein's General Theory of Relativity, has been scheduled to launch on April 17. The spacecraft will use four precise gyroscopes to determine how space and time are distorted by the gravity of the Earth and its rotation. The spacecraft will orbit the Earth once every 90 minutes, and gather data for more than a year, comparing any drift in its gyroscopes to the position of a guide star.
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Here's the latest desktop wallpaper of Saturn (1024x768), taken by Cassini when it was 56.4 million kilometres from Saturn. The resolution is about 25% better than its last full image, taken a month ago, and you can see fine details, like spots in the atmosphere. Three of Saturn's moons are also visible in this image: Mimas, Dione, and Enceladus. Cassini will arrive at Saturn this summer.
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The European Space Agency will be supplying technology to assist adventurer Bertrand Piccard's attempt to fly a solar-powered plane around the world. Piccard was part of the team that successfully flew a balloon around the Earth. The solar powered plane will have a 70-metre wingspan (larger than a Boeing 747), and carry enough batteries to be able to fly in the night as well. The plane would fly at an altitude of 10 km; well above the clouds to capture all the available sunlight. The first round-the-world attempt will be made some time after 2009.
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Although more than 100 planetary systems have been discovered, astronomers have only found large, Jupiter-sized planets. The real prize will be to discover Earth-sized planets in orbits where liquid water could be present. A new simulation by a team from Open University "injected" Earth-sized planets into the habitable zone of the star systems already discovered. About half of the systems already found could have Earth-sized planets in stable orbits in the habitable zone. It will still be several years before there are instruments built that can detect them.
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A survey with the Anglo-Australian Telescope (AAT) has revealed dozens of miniature galaxies the nearby Fornax galaxy cluster. These are a class of galaxies known as "ultra compact dwarfs" (UCDs). These objects were completely unknown until a few years ago, and now astronomers believe that they are very common. Perhaps they are leftover primordial building blocks that merged together to form larger galaxies. They are incredibly small, only about 120 light-years across, but they can contain tens of millions of stars.
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Venus, currently the brightest "star" in the sky, will spend the next few days passing through the Pleiades star cluster, making for a beautiful sky show. Venus is easy to see, it's that blazingly bright "star" high in the Western sky after sunset. Pleiades is much dimmer; a collection of young stars that looks like a miniature dipper that's hard to see in polluted city skies. On April 2, Venus will be right below the cluster; on April 3 it will be in the handle; and then April 4 it will have passed completely through. Find some dark skies over the next few nights to really appreciate the view - it won't happen again for another 8 years.
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Saturn's moon Titan is the largest in the Solar System; at 5,150 km in diameter, it's larger than Mercury and Pluto. It's unique because it has an unusual hazy atmosphere of nitrogen, methane, and hydrocarbons. The Voyager spacecraft took a quick look at Titan, but Cassini and the Huygen spacecraft will make detailed observations when they arrive later this year. Until then, huge observatories on Earth are working to gather as much information as possible about Titan. This will help give some perspective when the spacecraft arrive, and optimize the data they gather.
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Instead of sending single, high-risk spacecraft to explore the solar system, researchers are thinking of ways to send fleets of co-operating spacecraft to get the job done. There are many advantages to this method: decreased risk of losing the whole mission if a spacecraft fails, lowered launch costs, the ability to replace a failed instrument by sending a replacement. Swarms of rovers could crawl the surface of Mars, or explore the oceans of Titan.
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When the European Space Agency's Huygens probe reaches Titan early next year, it might encounter a hydrocarbon ocean different from anything we have here on Earth. Researchers have calculated what these oceans might look like, and found that the waves might be 7 times higher, but move more slowly and be further apart. Other scientists think Titan's surface is covered by an icy hard layer or maybe a hydrocarbon sludge. We'll find out for sure when the probe reaches Saturn's moon on January 14, 2005.
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In order the represent the Universe mathematically, physicists use a handful of constants, such as the speed of light, or the gravitational constant. One called the "fine structure constant", or alpha, helps describe how the forces hold atoms together and interact with light. Researchers recently revealed that alpha might have changed over the history of the Universe, but a new study from the European Southern Observatory refutes this evidence. By studying the light from a distant quasar with a high degree of precision, they found that alpha doesn't seem to have changed over time.
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Mark Mortimer reviewed
Lost in Space yesterday (
read the review), but he had a few more questions to author Greg Klerkx about his opinions about NASA and the impact of space exploration on society. Considering the book was released just before the new Bush Moon/Mars policy was announced, many of Klerkx's insights into the space agency become more relevant as the agency works to implement a return to the Moon. Mark put his questions to Greg, and here's what he had to say...
Scientists consider the discovery of methane in the Martian atmosphere to be one of the strongest indicators of habitable conditions for life. Methane can be produced through both biological and non-biological processes, but it degrades very quickly - it should disappear within 300 years in the Martian atmosphere. So what's producing it? The last period of volcanism seems to be millions of years ago (Olympus Mons was active 100 million years ago). That's doesn't necessarily mean life, though. There could still be volcanic vents gassing methane which haven't been discovered.
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When the ESA's Rosetta spacecraft reaches Comet 67P/Churyumov-Gerasimenko, it will send down the Philae lander to the surface. Landing on a comet has never been done, and it's as hard to do as it sounds. The lander will need to be able to deal with any kind of surface, from solid ice to fluffy snow. The comet's gravity is very weak, so the spacecraft could bounce off the surface if it descends too quickly. The lander is equipped with pads that spread its weight over a large area to stop it from sinking into powdery snow. It also has a harpoon that will fire as it gets close to stop the lander from drifting back into space. We'll find out if it works in 2014.
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The European Space Agency has confirmed reports that Mars Express has measured methane in the Martian atmosphere. The presence of methane - 10 parts per billion - was confirmed using the spacecraft's Planetary Fourier Spectrometer (PFS), which can detect the chemical in trace amounts. This isn't a lot of methane, but it has to be produced by some ongoing process such as volcanoes... or by life. The spacecraft will continue to measure the presence of methane in the atmosphere, mapping out the planet to find where it's concentrated. This will help to confirm or rule out volcanic gasses.
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Lost In Space, The Fall of NASA and the Dream of a New Space Age by Greg Klerkx, is a book about space which could have easily been entitled "Space Dreamers versus the Establishment". Of course there is no harm in dreaming and dreams are an essential part of being an abstract thinking human being. However, reality, like an extremely cold shower, can reduce dreams to a ghostly image trapped somewhere in the back of your mind. Greg Klerkx sees his dream of space, a defining element of our species, getting a thorough dousing from both big business and government - and he doesn't like it.
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