This image of a Martian crater was taken by the European Space Agency's Mars Express spacecraft in May, 2004. The crater is unevenly weathered, with a gentle slope on the wind-facing side, and a steep slope on the lee-side - on Earth these features are called ?barchanes?, and usually form in arid regions. There's a dune field on the bottom of the crater, that seems to be composed of sand of volcanic origin; how it got to the bottom of this crater is a mystery.

Planet hunting has traditionally only been possible with very large telescopes, capable of detecting tiny changes around distant stars which indicate the presence of planets. But now a team of astronomers have found their first extrasolar planet using a 4-inch telescope essentially developed with off-the-shelf equipment. The new Jupiter-sized planet is located about 500 light-years away, and was discovered using the transit method, which looks for a dip in a star's brightness as a planet passes in front. The team surveyed 12,000 stars in an area half the size of the Big Dipper's bowl, and turned up 16 candidates for planets. Follow up observations with larger observatories confirmed which ones had planets, and which didn't.

This is a detailed image of an exploded star called Cassiopeia A, taken by the Chandra X-Ray Observatory. The space-based observatory focused on this remnant for 1 million seconds (just over 11 days), and revealed the bright outer green ring 10 light years across which was generated by the shockwave from the supernova explosion. Two large jets extend outside this shockwave on opposite sides, and contain large quantities of silicon. This means they were formed early on in the explosion; otherwise, they'd contain mostly iron from the star's central regions.

NASA's Spirit rover has dug up plenty of evidence on slopes of "Columbia Hills" that water once covered the area. Spirit has been inspecting an outcrop called "Clovis" on a hill about 9 metres (30 feet) above the Gusev Crater plains, and it's found that liquid water changed the composition of the rock. Unlike rocks in the plains, which have coatings and veins created by small amounts of water, these formations have been deeply affected by water over a long period of time.

Scientists have used data from NASA's Galileo spacecraft to uncover strange rocky lumps underneath Ganymede's icy shell. One theory is that they're rock formations, lodged deep in the ice and held up for billions of years. The data was gathered by Galileo during its second flyby of the moon in 1996. This discovery challenges theories about the thickness and strength of Ganymede's ice - you would expect the rocks held up at the top, or resting at the bottom, but not somewhere in the middle. Galileo was crashed into Jupiter nearly a year ago.

NASA's Genesis spacecraft has nearly returned to Earth with its precious cargo of particles from the solar wind. On September 8, the spacecraft's sample return capsule will enter the Earth's atmosphere, and it will be captured in midair by a helicopter in Utah. The particles were collected over the course of 27 months, and captured in hexagonal wafers of pure silicon, gold, sapphire, and diamond. These are so fragile, that engineers didn't want to risk it actually striking the ground and damaging some of these wafers. Two helicopters will be in the air as the capsule parachutes down, and they should have 5 opportunities to snag it before it hits the ground.

Here's a question that's surprisingly difficult to answer: how old is the Milky Way? A team of astronomers have used the European Southern Observatory's Very Large Telescope to get an approximate age of 13.6 billion years, give or take 800 million. They reached this estimate by studying some of the oldest stars in our galaxy, which are located in globular star clusters, and born together in the same cloud of dust at the same time. They made difficult observations of a substance called Beryllium-9, which has been accumulating throughout the Universe since the Big Bang.

One experiment on board the European Space Agency's Rosetta spacecraft will let it cook particles from a comet in a miniature oven, and then "smell" the results. When Rosetta arrives at Comet 67P/Churyumov-Gerasimenko, it will send down a small spacecraft to actually land on its surface. This lander will be able to scoop up and drill samples from the comet's surface and then place them in an Evolved Gas Analyser. This tiny oven can heat the particles to 800 degrees Celsius which converts them into gas which can then be analyzed to understand what chemicals are present.

This image was taken by the European Space Agency's Mars Express spacecraft, and shows a system of outflow channels called the Dao Valles and Niger Valles; it was taken in June 2004, during the spacecraft's 528th orbit. The eroded channels are in a region of Mars that's near the southern flank of the Hadriaca Patera volcano, so they could have been created by fast moving lava "running off" during an eruption.

Cassini has uncovered two new mini-moons of Saturn, orbiting between Mimas and Enceladus. The new moons have been dubbed S/2004 S1 and 2/2004 S2, and scientists estimate that they're approximately 4 km (2.5 miles) in diameter. They were detected using automated software that scans through images taken by Cassini to look for moving objects. Scientists have two theories about moons this small: they could have survived since the formation of the Solar System, or they could have formed more recently by particles from Saturn's ring accumulating together.

A new image of Abell 2125, taken by the Chandra X-Ray Observatory, shows several intergalactic clouds of hot gas in the process of merging together; they seem to be in the process of creating a single massive galaxy cluster. Chandra's resolution allows astronomers to distinguish the clouds from the individual galaxies inside it.

An astronomer from the University of Hawaii has captured a detailed image of a dust disk around a new star; structures in the disk show evidence of planets. The photo is of a star called AU Microscopii, which is 33 light-years away, and the closest known star with a visible disk of dust. Dr. Michael Liu used the infrared capabilities of the giant twin 10 metre (33 feet) telescopes of the Keck Observatory, and saw clumps in the stellar disk; it should be smooth and featureless if there weren't any planets.

Globular star clusters - groupings of millions stars in close formation - are some of the most beautiful objects in the sky. Our own Milky Way has about 200 of them, but astronomers believe we used to have many more. Astronomers think that these star clusters might actually be all that remains from irregular dwarf galaxies were consumed by the Milky Way and had their outer stars stripped away. A team from Harvard and the Carnegie Institute of Washington observed 14 globular clusters in a distant galaxy, and realized that they're so large, they nearly overlap the size of small galaxies, and have many similar characteristics.

NASA's Genesis spacecraft made an important flight correction maneuver on Monday, which put it on course to return to the Earth after more than three years in space. Genesis has spent this time collecting particles of the solar wind on ultra pure wafers of gold, sapphire, silicon and diamond. On September 8, it will send a sample return capsule into the Earth's atmosphere, which will be caught by specially trained helicopter pilots. The particles will then be analyzed by scientists in laboratories around the Earth.

The Hubble Space Telescope has revealed an unusual situation where a young, hot star is carving out a cavity in a region of space that was once filled with cold, dense material. The massive star is known as N44F, and its stellar wind is moving nearly 5 times as fast as our Sun's solar wind. It's also ejecting 100 million times more material than the Sun. The fast moving torrent of particles collides with the colder surrounding material, pushes it away, and heats it up. N44F is in the Large Magellanic Cloud, located 130,000 light-years from Earth in the direction of the southern constellation Dorado.

Okay, new background. This time you'll be switching your computer desktop to show the Little Ghost Nebula - known to astronomers as NGC 6369 - taken by the Hubble Space Telescope. In the eyepiece of a small telescope, this planetary nebula looks like a ghostly ring surrounding a faint dying star. At some point thousands of years ago, the central star expanded in size to become a red giant star, and then expelled its outer layers. The blue-green ring is the expelled material, which now reaches a light-year in size.

The European Space Agency's Cluster spacecraft have helped answer a 17-year mystery about how the magnetosphere, a magnetic bubble that surrounds the Earth, keeps filling up with electrified gases, when it should be acting as a barrier to keep them out. The four Cluster spacecraft found huge swirling vortices of gas at the outer edges of the magnetosphere caused by interacting flows of solar wind. As they collapse, they force material into the magnetosphere, filling it up.

This is the best picture that Cassini's taken so far of Hyperion, one of Saturn's smaller moons (266 kilometers, 165 miles across ). The picture was taken on July 15, when Cassini was about 6.7 million km (4.1 million miles) away. Hyperion has an irregular shape, and it's known to tumble erratically as it orbits around Saturn. Cassini will get a much closer view when it does a flyby on September 26, 2005.

Tonight's the night when the Perseid meteor shower reaches its peak of 60 meteors/hour, and if we're lucky, a new filament of material from Comet Swift-Tuttle will give the event and extra boost. One way to make the moment last is to capture images of meteors with your camera; but, it's as hard as it sounds. First, you want to have the darkest skies you can find, and don't start until after 9:00pm. Use a standard 35 mm camera secured to a tripod, and use very fast film: ISO 400, 800 or 1,000 is recommended. Pick and area of sky, focus on infinity, and then start your camera's exposure, and then stop when a meteor streaks through the area. Don't be afraid to experiment.