How will the Universe end? Right now cosmologists have two equally distressing scenarios mapped out for the long term fate of the Universe. On the one hand, gravity might slow down the expansion of our Universe so that it coasts to a stop and possibly even collapses back down into a Big Crunch. On the other hand, the expansion of the Universe could continue indefinitely thanks to the acceleration of dark energy. We would face a cold, lonely future as other galaxies fade away into the distance. My guest today is Eric Linder from the Lawrence Berkeley National Laboratory and he's proposing experiments that could help us learn which of these two fates await us.

Saturn's moon Titan has long held a special fascination to astrobiologists. Its thick atmosphere is largely composed of nitrogen and organic molecules which are the building blocks of life. At a frigid -178 C (-289 F), however, it's much too cold to support life. But there could be some habitable locations on Titan, you just have to look carefully. Methane clouds around Titan indicate that it probably has an active cycle similar to the water cycle here on Earth. There could be areas where get warm enough on Titan for life to gain a foothold.

The time frame for the formation of new planets appears to be getting shorter than previously believed. Astronomers have discovered gaps in protoplanetary disks that suggest there are gas giants forming there. One star, GM Aurigae, is a younger version of our own Sun and the gap in its disk is at about the same location as our own gas giant planets. Since GM Aurigae is only 1 million years old, these results challenge the traditional theories that planets slowly formed over many millions of years.

An Italian team of astronomers have found a gamma ray burst that blew up 12.7 billion light-years away - the most distant ever seen. Astronomers have calculated that it exploded with 300 times more energy than our Sun will put out in its entire 10+ billion year lifespan. The blast was discovered by NASA's Swift satellite, which is dedicated to discovering these powerful explosions.

Astronomers have spotted a dusty disc around an old, dead star. This star is similar to what our own star will look like billions of years from now. What's unusual, however, is this dust cloud. It should have disappeared long ago; either sucked into the star, or blasted away by intense radiation. One theory is that a planet is still orbiting the dead star, and is continuously shedding material to create this dust.

The frame-filling view of Saturn's moon Rhea was taken by Cassini on August 1, 2005. Although in this image, Rhea looks quite similar to our Moon or the planet Mercury, it's actually covered in thick ice which would melt if it ever got as close to the Sun as Mercury. Rhea is 1,528 kilometers (949 miles) across, and you can see one of its larger craters, Izanagi, near the middle of the moon.

When humans return to the Moon in the next decade, they'll be facing a dangerous combination of cosmic rays and solar flares. Astronauts will need to avoid getting too much radiation, so NASA is working to better understand risks. The upcoming Lunar Reconnaissance Orbiter (LRO) will carefully measure and map the Moon's radiation environment. It will also have a special instrument designed to simulate how this radiation will affect the human body.

When Deep Impact excavated a crater in Comet Tempel 1, it released a spew of material that has existed since our Solar System first formed, billions of years ago. By analyzing this material, scientists have come up with better recipes for how to make planets, comets and asteroids. They were expecting to see water ice and silicates, but they were surprised to see materials like clay and carbonates (ingredient in seashells), since it was believed they required liquid water to form.

John Chumack took this picture of the crescent Moon and Mercury from Dayton, Ohio. John used a Canon 10D and 180mm lens at F5.6 on 400ISO for 1 sec. exposure while mounted on a tripod.

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.

Shevill Mathers took this picture of a recent solar prominence on the 4th, September from Tasmania, Australia.

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.

NASA and Sandia National Laboratories have been using a powerful solar tower to test new spacecraft materials. The tower reflects and focuses the Sun's radiation to blast spacecraft shields with the equivalent of 1,500 suns. This research effort is tied to a potential future mission to Saturn's moon Titan, which orbits in a very high-radiation environment. They have mimicked Titan's nitrogen-rich atmosphere for the tests, and the shield materials seem to have passed with flying colours.

Researchers at the Washington University in St. Louis have developed a "field guide" for planet hunters searching for other Earths. They modeled the chemistry of silicate vapour and steam rich environments, similar to the early stages when an Earthlike planet is forming. During this stage, the planet is covered with a magma ocean which vapourises. This is a very distinct moment in the lifetime of a planet, and should be detectable because silicon monoxide gas is easy to see in infrared and radio wavelengths.

New observations from the Hubble Space Telescope indicate that the largest asteroid in the Solar System, Ceres, might have huge reserves of water ice under its surface. Ceres is approximately 580 miles (930 kilometers) across, and resides with many other asteroids in a belt of material between Mars and Jupiter. Ceres' crust shows evidence of water-bearing minerals. In fact, if Ceres is 25% water, it would have more fresh water than what we have here on Earth.

This is an image of the Biblis Patera volcano's caldera which was taken by the ESA's Mars Express spacecraft. Biblis Patera is nearly 170 km (106 miles) long, 100 km (62 miles) wide, and its summit is 3 km (1.9 miles) high. The bowl-shaped caldera might have formed when a magma chamber collapsed during an eruption of the volcano.

Even though Deep Impact smashed into Comet Tempel 1 several months ago, scientists are still analyzing the data gathered before and after the collision. Very few close up pictures of comets have ever been taken, so the data gathered by Tempel 1 is very valuable, and sometimes surprising. The nucleus of Temple 1 has layers that show in topographic relief, ranging from smooth surfaces to impact craters. It's also extremely porous, which allows the surface to heat up and cool down almost instantly when hit by sunlight.

Cassini has found that Saturn, like the Earth, has many different kinds of clouds. Some are hazy bands, high up in the planet's atmosphere, while others seem to go much deeper. These deeper clouds live about 30 km (19 miles) under the cloud surface and seem to be isolated features that have different shapes, like ovals, donuts, and swirls. There are also dozens of "lanes" which go completely around the planet, similar to the bands which can be seen in many telescopes, but are much narrower.

Greetings, fellow Sky Watchers! While the Moon will figure prominently in our studies this week, let's start off with telescopic challenge - "Barnard's Galaxy". Do you only have binoculars? Don't worry, the NGC 6871 will surely please you. If you have eyes, then you're in luck as the Moon, Jupiter, Venus and Spica dazzle the western skyline and Piscid meteor comes to call. So, get thee out under the stars and in the moonlight, because...

Here's what's up!

Cassini scientists have announced a host of new findings about Saturn's rings, including some new knotted structures in the planet's F ring. One of the major discoveries is that parts of Saturn's D ring (its innermost ring) have relocated and dimmed. In fact scientists have been able to track fairly significant changes between when Voyager first visited Saturn 25 years ago. The delicate G ring seems to contain faint arcs, which might be hiding additional planets. And most surprisingly, knots in the planet's F ring seem to be arranged like a coiled spring winding around the planet.

The ESA's Integral space observatory and NASA's Rossi X-ray Timing Explorer spacecraft have found a rapidly spinning pulsar in the process of consuming a neighbour. This discovery supports the theory that pulsars spin so quickly because they pick up material from a companion, which increases their mass. Pulsars were once stars more than 8 times as large as our Sun, but their intense gravity compacted them down to a size of about 20 km (12 miles) across.