Shuttle managers decided on Wednesday that Discovery's leading wing edge is safe for it to make re-entry. This is the area that was damaged by falling foam during Columbia's launch, and caused the catastrophe during re-entry. High resolution photographs have analyzed every part of Discovery, and the only concerning area were some protruding tile gap fillers, which will be fixed during a spacewalk on Wednesday.

NASA's Messenger spacecraft made a successful Earth flyby this week, getting a gravity boost that will propel it into the inner solar system. This maneuver put it on course towards Venus, where it'll get another gravity assist to put it on track towards its final destination: Mercury. It won't get into a final, stable orbit around the closest planet to the Sun until 2011. Messenger took several photographs of the Earth as it came by, using this opportunity to calibrate its scientific equipment.

This Cassini image of Saturn's moon Rhea shows a bright, white spot in its leading hemisphere. This bright feature could have come from a large impact, and has been examined by Cassini several times from different angles. Cassini took the photo on June 25, 2005 when it was approximately 1.1 million km (700,000 miles) away from the moon.

Stars, stars, everywhere are stars. What's that one? Oh, it's an aeroplane flying by, oops. Moments such as this would be really bad starts to an evening out viewing the skies. However, as in the word's of the illustrious Zaphod, "Don't panic". Robin Kerrod in his book The Star Guide: Learn How to Read the Night Sky Star by Star separates the lowly flashing lights of fireflies from the twinkles overhead using a wonderful combination of maps and pictures, together with some judicious text. With this book, the stars and night sky need no longer be a mystery.

In this image of Saturn, taken by Cassini, it's possible to see how Saturn's atmosphere distorts the rings right next to the planet. This happens because Saturn's atmosphere refracts the light coming from the rings, similar to how object in the water look distorted and out of position.

Cepheid variables are one of the most accurate tools astronomers can use to measure the distance to objects in space because the period of their pulsation is directly tied to their brightness. An international team of astronomers have used this method to calculate the distance to galaxy NGC 300 which is in the Sculptor Group. The team found more than 100 Cepheid variables, and then used them to calculate the distance to be 6.13 million light-years away; give or take 3%.

Instead of being a dead, icy moon, Cassini has found that Enceladus is actually quite active. This moon of Saturn has a huge cloud of water vapour over its southern pole, and warmer fractures. The moon is relatively close to Saturn, so the intense tidal pressures are keeping it warmer than it should be. This is the same interaction between Jupiter and Io that keeps the moon covered in volcanoes.

Greetings fellow SkyWatchers! Dark skies this week means a chance to further our in-depth look at globular clusters as we explore classifications, structure, population and distance. What better way to start than with the M22? Even if you only have binoculars or a small telescope, there will be many studies here to intrigue both you and the seasoned observer as well. So open your eyes to the skies, because...

Here's what's up!

Mike Salway took this picture of Crux and Centaurus on the 9th July, 2005 from Kulnura, on the Central Coast of NSW, Australia. This image was taken with a Sony Cybershot 5.1mp digicamthe and is a result of 5 images @30s each (ISO400).

Do you have photos you'd like to share? Post them to the Universe Today astrophotography forum or email them to me directly, and I might feature one in Universe Today.

Physicists have used the Brookhaven National Laboratory's Relativistic Heavy Ion Collider to create quark-gluon plasma; a mysterious form of matter that was probably present in the first moments after the Big Bang. The team created it by smashing the nuclei of gold atoms together at relativistic speeds. The resulting explosion of particles lasted just 10^-20 seconds. Astronomers think that large neutron stars might go into a quark-gluon phase before they collapse into black holes.

Is the discovery of methane in Mars' atmosphere the first direct evidence of extraterrestrial life? Extraordinary claims require extraordinary evidence, so scientists are working to figure out what it will take to know for sure. The best way to know for sure will be to analyze the ration of carbon-12 to carbon-13. Living creatures prefer to pick up carbon-12 as they assemble methane, so a larger amount of this isotope will be a telltale sign. Unfortunately, detecting this isotope is best done by spectrometers on the surface of Mars, so future landers/rovers with more sensitive instruments will be required.

Astronomers have discovered a new planet orbiting our Sun, which is larger than Pluto. It's located 97 times further than the Earth from the Sun. This new, 10th planet was actually first photographed in 2003 by the Samuel Oschin Telescope at Palomar Observatory, but it took this long to study and confirm its size and orbit. A name has been proposed to the International Astronomical Union, which is making its decision.

When astronomers discover a supernova, it's too late to learn much about the star before it exploded. Even if astronomers have a picture of its home galaxy before the star went supernova, there are often too many stars in the area to pick out the progenitor star. An international team of astronomers got a lucky break when a supernova exploded in the relatively nearby Whirlpool Galaxy (M51) which was well photographed by Hubble. By comparing archived pictures with a new photo containing the supernova, they were able to find the exact star that exploded.

Scientists from NASA, MIT and other institutions have developed a comprehensive simulation of the Earth's climate that accurately models ocean, ice, land and atmosphere. This new model, called the Earth System Modeling Framework (ESMF) pulls in data from a variety of sources, such as satellites and ground observations. The research team will be releasing the software publicly on the internet to the scientific community so they can use the simulator to study various processes in the Earth's environment.

Two of Saturn's icy moons, Mimas and Tethys, circle the planet in this infrared image of the Ringed Planet taken by Cassini. Mimas is 397 kilometers (247 miles) across. Tethys is 1,071 kilometers (665 miles) across. It's also possible to see a large, doughnut-shaped storm near Saturn's southern pole which is at least 1,600 km (1,000 miles) across.

NASA is helping researchers build machines and materials at the smallest scales - known as nanotechnology - to enable future space explorers. One example of this research is in the development of carbon nanotubes, which could have 100 times the strength of steel at 1/6 the weight, and used in the construction of a future space elevator. Nanofactories could churn out spacecraft parts where atoms are placed individually with atomic precision.

This image, taken by ESA's Mars Express spacecraft, shows a large patch of water ice sitting on the floor of a Martian crater. The unnamed impact crater is located on Vastitas Borealis, a broad plain that covers much of Mars' far northern latitudes. This patch of ice seems to be present all year round, as the temperature and pressure don't get high enough for the ice to sublimate away into gas. There are also faint traces of ice on the inside wall of the crater.

NASA engineers are working on a new instrument that could peer through rock and dirt on Mars to see evidence of life under the surface. The Neutron/Gamma ray Geologic Tomography (NUGGET) would be wielded by a Martian rover, and aimed at suspicious rocks. By releasing a focused beam of neutrons, some of atoms in the target rock will capture them and give off a characteristic gamma ray signature, measurable by the instrument. Ancient fossils embedded in the rock would be revealed by their chemicals.

Sailing through space on nothing but photons from the Sun is a nice dream, but we're still years away from the reality. NASA took their next step in June, however, when they tested a 20-metre (66-foot) prototype solar sail at their Plum Brook research facility. They successfully deployed the sail using an inflatable boom designed to unfurl the sail from a box the size of a suitcase and then keep it rigid in space.