As Cassini nears Saturn, new details are becoming clearer, including the banded clouds that make up the planet's atmosphere. When Cassini took this latest image on April 16, it was 38.5 million kilometers (23.9 million miles) away. It's close enough now that the entire planet no long fits inside a single frame of the spacecraft's narrow angle camera. The banded clouds follow Saturn's lines of latitude, which are created by the planet's rotation. Cassini will reach Saturn in July, 2004.

String theorists have a problem. They have a set of theories which could explain how all the forces in the Universe are connected. Unfortunately, it depends on the existence of tiny vibrating strings which are so small they could never be seen directly. One strategy, proposed by physicists from Yale, would be to look at the afterglow from the Big Bang, which covers the entire sky. The small strings could project much larger shadows onto this radiation which would be light-years across, and detectable from Earth.

The European Space Agency's Proba satellite has taken a high resolution image of a segment of the Great Wall of China. There has been much debate about whether or not the wall is visible from space; Yang Liwei, China's first spacefarer, wasn't able to see it. Astronaut Eugene Cernan said that at an altitude of 160 km (100 miles), he was able to see it. Proba orbits at an altitude of 600 km (372 miles), and was designed to demonstrate several Earth observation techniques.

Astronomers have had plenty of time to observe the fluctuations of the Sun, but until now, it's been unclear if other stars go through the same cycles. But new data gathered by the ESA's XMM-Newton X-Ray Observatory has found a similar cycle of radiation in a distant star. The X-ray brightness of HD 81809, located 90 light-years away in the constellation of Hydra, has varied 10 times over the past 2 and a half years, reaching a well defined peak in mid 2002 - just like the Sun's 11 year cycle of sunspot activity.

A new image released from the Chandra X-Ray Observatory shows the giant elliptical galaxy M87. Bright jets can be seen at the heart of the galaxy, which are generated by a supermassive black hole, and it looks like it's been actively reshaping the galaxy for hundreds of millions of years. Two circular rings are visible extending away from the centre of the galaxy, and were likely caused by two massive explosions millions of years ago.

Here's a 1024x768 desktop wallpaper of a new nebula image taken by the Hubble Space Telescope. Its technical designation is HD 44179, but it's better known to astronomers as the "Red Rectangle" because of its unusual shape when seen from ground-based telescopes. The star at the heart of the nebula began like our own Sun, but now it's shedding off layers into space, and nearing the end of its life.

As a show of support for President Bush's space exploration initiative, 13 US space advocacy and policy groups have formed an alliance. The groups include: Aerospace Industries Association, Aerospace States Association, American Astronautical Society, American Institute of Aeronautics and Astronautics, California Space Authority, Florida Space Authority, The Mars Society, National Coalition of Spaceport States, National Space Society, The Planetary Society, ProSpace, Space Access Society and Space Frontier Foundation. The first goal for the group will be to gain broad congressional support for the new vision - perhaps it won't be difficult considering the groups have 1 million members combined.

NASA named its latest batch of astronauts; the 11 candidates include three teachers, who were selected from over 1,000 candidates. The introduction of the new astronauts comes at a time when the space shuttle fleet is still grounded because of the Columbia disaster - they probably won't fly until 2009. The candidates are Joseph Acaba, Thomas Marshburn, Christopher Cassidy, R. Shane Kimbrough, Jose Hernandez, Robert Satcher, Shannon Walker, James Dutton, and Randolph Bresnik.

European astronomers have confirmed a new class of objects, known as "very hot Jupiters", which are large, extremely hot, and orbit their parent star in an orbit that only takes a couple of days. They used the "transit method", which measure the brightness of a star over a long period of time to watch for a periodic dimming; an indication that a planet is passing in front. As part of a new survey of 155,000 stars, the astronomers have found 137 transit candidates, and confirmed 2 planets so far using other techniques for finding extrasolar planets.

NASA is currently making a difficult decision about whether to send its Opportunity rover down into Endurance Crater, which is 130 metres wide, and deep enough that the rover might not be able to climb back out. It's clear that there's some interesting science to be gathered in the crater, including more exposed rock surfaces. Opportunity will crawl around the rim of the crater and search for an ideal ramp that it could use to enter and exit safely.

X Prize candidate Canadian Arrow announced this week that they will begin unmanned flight tests of its rocket this summer. Over the course of four months, beginning in August, the team will test their rocket's abort system which enables the crew cabin to blast away from the rest of the rocket while it's on the pad. They will also test flight aerodynamics to ensure the rocket will be able to fly to its designed altitude as required by the X Prize.

NASA announced two new missions today that will help scientists better understand the Earth's environment. The Aeronomy of Ice in the Mesosphere (AIM) Small Explorer will determine the causes of the Earth's highest altitude clouds, which sit right at the edge of space. The Time History of Events and Macroscale Interactions during Substorms mission (THEMIS), will fly five spacecraft in formation to help understand the colourful Northern and Southern lights. Both spacecraft are expected to launch in 2006.

The privately funded X Prize received a helpful boost this week with a large investment from entrepreneurs Anousheh and Amir Ansari. The unspecified amount of money will be used to cover operation costs of the organization, including the insurance money that's backing the $10 million prize. The name of the prize has been changed to the Ansari X Prize, to recognize their contribution. 26 teams have registered to win the prize, which expires on January 1, 2005, if nobody can send their privately-built spacecraft into suborbital flight.

New images obtained with the European Southern Observatory's Very Large Telescope show the immediate surroundings of the supermassive black hole at the heart of active galaxy NGC 1068. This central region of an active galaxy can outshine the rest of the galaxy because its black hole is consuming material; NGC 1068's monster black hole would have to be 100 million times the mass of our Sun to account for the amount of radiation pouring out of it. These new images resolve down to only 3 light-years away from the black hole.

NASA's Cassini spacecraft has delivered some early images of Saturn's moon Titan; a mysterious world obscured by thick clouds. Some surface features only seen from Earth-based telescopes are now visible to Cassini. The spacecraft used its narrow angle camera's spectral filters, which are designed to penetrate the thick atmosphere to create the images. Cassini's first good opportunity to see Titan will be when the spacecraft enters orbit around Saturn in July; it'll fly past the moon at a distance of only 350,000 km.

Just a little more than a year ago, the space shuttle Columbia disintegrated on re-entry thus bringing the second calamity to the shuttle fleet. A lot has been written regarding this event and, of course, the CAIB has completed its review of what happened, but the personal touch brought forward by Michael Cabbage and William Harwood in Comm check... The Final Flight of Shuttle Columbia is a worthwhile addition. Their chronological narrative takes the reader on a sad and inciteful journey of the hopes, dreams and hard reality that make up a space mission.

When scientists announced that they had found evidence of past life in a meteorite from Mars in 1996, it set off a controversy that has been going back and forth even now. The latest research, published in the journal American Mineralogist casts doubt that it's life that was in the space rock. The original discoverers believed that magnetite in the rock was formed by bacteria, but this new paper shows that it can also be caused by an inorganic process, which can be duplicated in the laboratory when iron-bearing carbonates decompose under high heat (such as atmospheric reentry).

NASA released a 180-degree view of Endurance Crater this week, a target Opportunity has been rolling towards for many days. After taking in the view, Opportunity will try a few spots around the rim of the 130-metre crater to see if it can drive down without rolling over - hopefully it'll be able to get back out again. Portions of the crater's sides appear almost paved with smooth rocks, while in other areas it has steep walls with exposed rock, similar to the crater Opportunity landed in. It should be a treasure trove of scientific data.