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.

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).

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.

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.