British astronomers have used a radio telescope called the Very Small Array to probe the cosmic background radiation; an afterglow from the Big Bang that gives insights into the rapid expansion of the early Universe. By combining their results with data from the WMAP satellite, they were able to see how the expansion went when the Universe was only 10(-35) seconds old. They found that temperature and density varied much wider than traditional estimates.

The US House of Representatives approved bill H.R. 912, which awards amateur astronomers who discover potential Earth-crossing asteroids up to $3,000. One award will be given to the astronomer who discovers the brightest object, and another to the astronomer who makes the biggest scientific contribution to Minor Planet Center's mission of cataloguing near-Earth asteroids. It's estimated that there are between 900 and 1,100 objects larger than 1 km - of which, 700 have already been tracked.

NASA's workhorse satellite Landsat 5 recently passed the 20 year mark of operations, beating original estimates that it would only last 2-3 years. Over the course of 100,000 orbits, the satellite has taken over 29 million images of the Earth, tracking human activity and changes in the planet's environment; and it's still working fine. Nothing lasts forever, though; the satellite is expected to run out of fuel by 2009 - a replacement should be launched before then.

Here's a 1024x768 wallpaper of the latest image released from the Hubble Space Telescope. It's of V838 Monocerotis, a nebula located about 20,000 light years away from Earth in the constellation of Monoceros. Hubble first began watching this object when the central red star flared up in 2002, illuminating a cloud of material that was probably ejected in an explosion tens of thousands of years ago. The object is likely to continue changing rapidly over the next few years as light continues to expand inside the shell of material.

Sojourner is the little robot that enthralled Earth in 1997. For the first time, a mobile construct of humans was being guided by humans on the surface of another planet. Andrew Mishkin is a systems engineer who worked on the Sojourner project at NASA's Jet Propulsion Laboratory (JPL) during the inception, birth, and life of this little rover. He uses his notes, official documentation, unofficial recollections and friendships to present Sojourner, An Insider's View of the Mars Pathfinder Mission - a book that is an historical reference, a guide to systems engineering, and an insight into the bureaucracy of government science departments.

Want an easy way to find Jupiter on Thursday and Friday? Just look for the Moon. On March 4th and 5th, the Moon and Jupiter will be side-by-side in the sky inside the constellation Leo. And right now, Jupiter is only 400 million kilometres away - that's close. If you have a small telescope, point it at Jupiter, and you should be able to see the planet's four larger moons, dusty bands across its surface, and maybe even the Great Red Spot.

During yesterday's press conference, scientists produced four pieces of evidence to support their claim that liquid water once acted on Mars in the region that Opportunity landed. One of these is the discovery of the presence of sulfates, which are likely formed by the action of water. There are microbes on Earth, which use sulfates as their primary source of energy, so they can be largely independent from the Sun. Perhaps something like this could be alive just under the surface of the Mars.

For a few hours on January 13, 2004, some astronomers believed that a 30-metre asteroid could strike the Earth in less than two days. The asteroid, named 2004 AS1, ended up passing 12 million kilometres away, but it demonstrates the difficulty asteroid hunters have searching for objects that could hit our planet. Had it struck, 2004 AS1 could have caused destruction on a city-wide scale. NASA currently has a program to search for asteroids larger than 1 km, and should locate them all by 2008. Other proposals have been suggested to search for smaller - and still dangerous - asteroids that threaten the Earth, but nothing has been approved yet.

Astronomers at UC Berkeley took advantage of the newly installed adaptive optics system at the Lick Observatory to get clear images of a massive star forming region. The system works by using a laser to create a false star in the sky. A computer tracks the atmospheric turbulence, and warps the telescope's mirror to compensate. The young massive stars that the team observed are usually too blurry when seen from the ground, so they made the perfect target for the adaptive optics system.

NASA announced today that liquid water once soaked the environment around Opportunity's landing site, raising the chances that life once existed on the Red Planet. This announcement came from Opportunity's detailed examination of a region of exposed rock on the side of the crater it landed in. By analyzing the rock with every instrument at its disposal, scientists now have conclusive evidence that liquid water once acted on this rock, changing its texture and chemistry. Opportunity's next job will be to determine if the rocky outcrop was actually formed by water, or if it's volcanic in origin. This means that there was probably a long period of time on Mars where the environment would have supported life.

In 1997, cosmologists Stephen Hawking, Kip Thorne, and John Preskill made a bet about what happens to a black hole when material is sucked into it. Do the characteristics of the particles somehow change the black hole so that a record of information is maintained? Or is all the information destroyed? A new solution based on string theory predicts that material sucked into the black hole is preserved as a tangle of strings, which fills its core to its surface. In theory, a black hole could be traced back to its original condition by following the trail of material consumed. Stephen Hawking and Kip Thorne need to pay up.

NASA's Spirit rover used its rock abrasion tool to dust off a rock called "Humphrey", and then backed away to see the whole rock with its thermal emission spectrometer - this should tell it what minerals are present in the rock. Once it completes this task, the rover will actually grind a hole to see under the rock's surface. Opportunity is also examining rocks on the other side of Mars, and it's getting ready to exit the crater that it landed in to search for evidence of past water on the plains.

Saturn's moon Titan has long intrigued astrobiologists as a possible environment that was similar to our own Earth's early history. Its atmosphere has the same pressure as Earth, and it could contain chemicals called tholins - a building block for life. The Huygens probe, currently piggybacking a ride on NASA's Cassini spacecraft, will measure the atmosphere when it arrives later this year, but researchers are working to simulate Titan's complex chemistry in a laboratory environment right here on Earth.

Astronomers have found hydrogen peroxide in Mars' atmosphere. The team gathered the data when Mars made its closest approach to Earth in the summer of 2003, using the 15-metre James Clerk Maxwell Telescope (JCMT) in Hawaii. Hydrogen peroxide is used as an antiseptic to kill bacteria on Earth, so it could help sterilize the surface of Mars. Many astrobiologists now think that the best chance of finding bacteria on Mars will be underneath the surface, which would be protected from this hydrogen peroxide and ultraviolet radiation from the Sun.

The European Space Agency's Mars Express spacecraft took this image of the caldera of volcano Hecates Tholus; it's 5300 metres tall, and the northernmost of the Elysium volcano group. The photo was taken during orbit 32, when the spacecraft was 275 km above the volcano.

Astronomers from the European Southern Observatory (ESO) have shattered the record for finding the most distant galaxy ever seen. By using a gravitational lens to magnify more distant objects, the team has found a galaxy which is 13.2 billion light-years away; the galaxy is being seen when the Universe was only 470 million years old. The young object is 10 times less massive than our own Milky Way, and looks like it was a building block for present day galaxies.

Astronomers from the University of California, Berkeley have discovered the nearest and youngest star with a visible disk of dust that could be a home for planets. The dim red star, AU Microscopium, is only 33 light-years away. It's half the mass of the Sun, and only 12 million years old (our Sun is 4.6 billion years old). The star was imaged using the University of Hawaii's 2.2-metre telescope atop Mauna Kea, which can block out the central star to reveal dimmer material.

A new animation built from a series of photos taken by NASA's Opportunity rover shows the Sun dimly setting in a hazy Martian sky. Although it's a pretty picture, the main purpose for this data is to let scientists calculate the amount of dust in the sky - currently it seems to be roughly double what Pathfinder measured in 1997. Opportunity is partway through its analysis of a piece of the exposed rock outcropping; after this it will exit the crater it landed in, and begin exploring the surrounding flatlands.

Now only four months away from its encounter with Saturn, NASA's Cassini spacecraft will be delivering weekly postcards as it approaches the ringed planet. Here's a 1024x768 desktop wallpaper image of Saturn, taken by Cassini on February 9, 2004, when the spacecraft was 69.4 million kilometres away - the smallest details visible are 540 kilometres across. Cassini will go into orbit around Saturn on July 1, 2004, and spend the next four years studying the planet and its moons.

The Mars rovers are starting to generate less power these days because Mars is starting to slip into Winter. In order to compensate for the reduced amount of light falling on the rovers' solar panels, engineers have begun a new lower-power communications plan. The rovers will only receive information in the morning, and transmit through Mars Odyssey twice a day. The rovers will also take more naps during the day to conserve battery power.