Cassini took this image of Dione set against giant Saturn as it approached the icy moon for its December 14th flyby. This picture, taken from 603,000 kilometers (375,000 miles), shows how Dione has colour variations across its surface, but it's largely gray. Several oval shaped storms are visible raging across Saturn's banded atmosphere.

The Subaru telescope captured this image of a dusty planetary nebula surrounding a star similar to our own Sun at the end of its life. Located 5,000 light-years away from Earth in the constellation of Cygnus, the nebula is very similar to the more famous Ring Nebula. When they reach the end of their lives, stars like our own Sun shed layers of gas and dust which pile up around the star, and are pushed outward. In this nebula, the material has reached a distance of 100 times the size of our Solar System.

The shape of the Helix Nebula has always been a bit of a mystery to astronomers; some theorized that it's donut-shaped, or it could even resemble a snake-like coil. But new observations from the Hubble Space Telescope have helped to shed some light on this issue. Researchers tracked the speed of material being expended from the central dying star, and came to the conclusion that it's actually two gaseous disks which are perpendicular to each other. One disk was expelled 6,600 years ago, and the other was fired off 12,000 years ago.

Astronomers had seen storms around Titan's south pole before, but now they've been discovered at the moon's mid-latitudes as well. The discovery was made using the Gemini North and Keck 2 observatories, which have adaptive optics systems capable of resolving Saturn's largest moon with great detail. These storms could be created by surface activities, like cryovolcanoes which could spew an icy mix of chemicals into the atmosphere. It could also be caused by seasonal temperature changes, like the weather here on Earth.

Just days after completing its second flyby of Titan, Saturn's largest moon, Cassini proceeded on to its next target: Dione, Saturn's 4th largest moon. The spacecraft came within just 81,000 kilometres (50,600 miles) of the moon and sent back a stream of close up images of its strange surface, which are now being analyzed by scientists.

Scientists were surprised to learn that the Earth's magnetic field can concentrate radiation from the Sun during powerful solar storms, even in places that were previously thought to be safe. One region is the gap between the two Van Allen radiation belts that surround our planet, which resemble two donuts, one inside the other. In between these belts is a relatively safe area that could be prime real estate for satellites because of the low radiation levels. During the extreme solar weather last year, that safe zone actually filled up with radiation and became quite hazardous for more than five weeks.

NASA has selected eight proposals for experiments that will be installed on the upcoming Mars Science Laboratory (MSL) rover, which will launch for the Red Planet in 2009. The instruments proposed for the minivan-sized rover include: a stereo video camera, a laser that can blast material off from 10 metres, a microscope, an alpha particle X-ray spectrometer, an X-ray diffraction/X-ray fluorescence instrument, a radiation detector, a descent camera, and a gas chromatograph mass spectrometer which would be able to detect organic compounds and chemicals produced by bacteria.

Engineers are making the final preparations for the launch of NASA's Deep Impact spacecraft, due to lift off from Cape Canaveral on January 12, 2005. The spacecraft will make a six-month journey to reach the nucleus of Comet Tempel 1, and then deploy a probe that will crash into it at 37,000 km/h (23,000 mph). The 1-metre square copper probe will completely vapourize, and should carve out a hole the size of the Roman Coliseum, which Deep Impact will be able to study as it passes the comet shortly afterwards. The impact will also be recorded by Hubble, Spitzer, Chandra, and dozens of Earth-based observatories.

NASA's Spirit Mars rover has found even more evidence that there was liquid water in the Red Planet's past. Scientists have identified a mineral called geothite, which is similar to the jarosite found by Opportunity, and forms only in the presence of water (gaseous, liquid or ice). The rovers previously found hematite, but this can sometimes form without water. Spirit will now climb further up the Columbia Hills to attempt to answer if the water was present on the surface, or just pooled underground.

NASA's Cassini spacecraft swept past Titan for the second time yesterday, this time on a more direct course, and passed by 1,200 kilometres above the surface. Once again the spacecraft's cameras took hundreds of images as Cassini drew closer to Titan, revealing the same surface features now associated with the landing site of the Huygens probe that is set to decend to Titan's surface in mid January.

Greetings fellow SkyWatchers! This week starts off on an exciting note as one of the most prolific and predictable meteor showers of the year happens tonight - the Geminids! Thanks to the one-day old Moon, this year dark skies could produce as many (or more!) as 100 meteors per hour during peak times. Think that's enough for one week? Then think again... Comet C/2004 Q2 Macholz is smoking up the southern skies and has become the premier object of December! As much as I hate to say it, the Moon is back again but that doesn't mean that we can't take the time to do some "shallow sky" work and explore lunar features. As always, there are things here for all observers, so join me on the dark side...

Because here's what's up!

When it's complete, the Giant Magellan Telescope (GMT) will be the world's largest observatory, with a primary mirror 25.4 metres (83 feet) across - 4.5 times the collecting power of any telescope on Earth. The GMT is scheduled to be completed in 2016, in a remote location in Northern Chile, which has some of the best viewing conditions in the world. The observatory will be built using 7 primary mirrors arranged in a flower pattern, and reuse the manufacturing equipment that helped build the Large Binocular Telescope mirrors now being installed on Mt. Graham.

Cassini took this image of Saturn's rings on October 27 as it swung past the dark side of the planet during its first close pass after it arrived. The image also contains three of Saturn's moons: Mimas, Janus, and Prometheus. Although it's normally quite bright, the B ring looks dark from this side, when it's not being illuminated directly by the Sun.

Some people sit in the tub, yell "Eureka", and come up with a brand new view of matter. Others can be riding a trolley home and at the sight of a clock initiate a whole new concept of time. Yet another more pedantic method is to follow government procedures to resolve riddles. Steven Dick and James Strick in their book, The Living Universe - NASA and the development of Astrobiology, narrate how this occurred for the new academic field of astrobiology. Though perhaps not as film-worthy as instantaneous flashes, the four decades of meetings, workshops and programs described therein show that this distinct academic area had an eventful and exciting coming of age.

As the year winds down, observers in the Northern Hemisphere may notice the days growing steadily shorter; while observers in the Southern Hemisphere notice the days getting longer. In addition, in the north the days are getting colder and in the south the days are getting warmer. All this happens while Earth is moving toward a point in its orbit known as the Winter Solstice. But what is the Solstice anyway?

Both Hubble and the Spitzer Space Telescope have provided astronomers with a view of planetary systems forming around other stars similar to our own Sun. Hubble viewed a young star, only 50 to 250 million years old, which could have gas giants, but its rocky planets would still be forming. This could be a view into what our Solar System looked like when it was first forming. Spitzer found 6 much older stars with planetary disks; closer to 4 billion years old, which is the age of our Sun. These stars are known to have gas giants, and probably have rocky planets as well.

Astronomers working with the European Southern Observatory took a series of images of the Tarantula Nebula (aka 30 Doradus), which is one of the most impressive objects in the Southern sky. Located 170,000 light-years away in the constellation of Doradus, the Tarantula Nebula got its name because the various patches of gas and dust look like the legs of a spider emanating from the central "body" of young hot stars. The gas is mainly just protons and neutrons which are kept apart by energetic radiation coming off the stars in the area.

Cassini took this beautiful picture of Dione, one of Saturn's larger moons, which has strange wispy streaks across its surface. The spacecraft will be getting a much better view of the 1,118 km (695 mile) moon in mid-December when it makes a closer pass.

A study by the National Academy of Sciences is suggesting that astronauts should be the ones to upgrade the aging Hubble Space Telescope, and not the robotic mission currently favoured by NASA. The independent panel of scientists was commissioned by NASA to review options for the aging telescope, and they delivered their report on Wednesday. They suggested that the difference in risk between visiting Hubble and the International Space Station is very small, while a robotic mission would be of similar cost and would be much more likely to fail.