Greetings, fellow SkyWatchers! This week will begin a series of studies of some of the oldest formations in our galaxy - globular clusters. The Moon will visit with Mars and lucky viewers in Australia will have a chance to see it occult the Pleiades! Not enough? Then hang on as we have not one - but two - meteor showers this week. So grab your binoculars, take out your telescopes and head for dark skies because...

Here's what's up!

NASA began the countdown for launch of the space shuttle Discovery on July 23. If all goes well, and there are no further delays, Discovery will blast off on Tuesday, July 26 at 1439 UTC (10:39 am EDT). They still have no resolution for the malfunctioning fuel gauge, but managers have said they'll be willing to let the shuttle fly, even if the problem resurfaces, because of redundant systems.

Saturn is about to go behind the Sun. For a few days, NASA won't be able to communicate with Cassini since it's currently in orbit the planet. As Saturn neared the edge on July 24, radio distortion from the Sun made communications with Cassini impossible. NASA expects to reacquire a signal from Cassini on July 27. This situation gives scientists an opportunity to probe the Sun's corona, since communications will have to pass through it. This photograph was taken by SOHO, which is parked in a gravitationally stable spot between the Earth and Sun.

Clyde Miller took this picture of Orion M42 from Brantford ON Canada.

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.

Clyde Miller took this picture of M5 on the 22nd June, 2005 from Brantford ON Canada.

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.

In this photograph, Cassini is looking through Saturn's rings to see the planet and one of its shepherd moons, Prometheus. The rings are casting a shadow onto the planet, and you can see the narrow, dense regions which are created by gravitational interaction with the shepherd moons. This picture was taken on June 3, 2005, when Cassini was 2.1 million kilometers (1.3 million miles) from Saturn.

With the evidence turned up by the Mars Exploration Rovers, the Red Planet was once warm enough to have liquid water flowing on its surface. But according to researchers at MIT that period happened a long time ago; more than 4 billion years ago, in fact. The team analyzed the amount of argon in various Martian meteorites. Since argon known to leak out of rocks at different rates depending on the temperature. they were able to provide this estimate for the age of the Martian deep freeze.

NASA's next mission to the Red Planet, the Mars Reconnaissance Orbiter (MRO), is in the final stages of preparation for launch. If all goes well, the spacecraft will lift off from Cape Canaveral atop an Atlas V on August 10, and begin the 7-month journey to reach Mars. MRO is carrying 6 instruments that will probe the planet's atmosphere, surface and subsurface and provide the most detailed examination so far.

One of the most mysterious places in the Solar System is right underneath your feet: the interior workings of the Earth. Since it's impossible to drill down more than a few km under the surface of the Earth, scientists have study how sound waves from earthquakes travel throughout the planet and get reflected as they bump into things. These sound waves have always acted differently than predicted in simulation. Scientists now think that iron, crushed under tremendous pressure, can significantly alter the speed and direction of these sound waves.