Bellatrix Orionis

Image credit: NASA/JPL-Caltech/Keck

 NEWS FLASH - A giant ring has been discovered around Saturn and is thought to be the largest of it’s rings.

Phoebe, one of Saturn’s furthest moons is within the newfound ring and is thought to be the source of it’s material.  The new ring is also very thick, it’s approximately 20 times the diameter of Saturn and would take one billion Earths to fill the ring.  The ring is composed of ice and dust particles which was spotted by NASAs Spitzer telescope which views objects in the infrared spectrum.

The discovery may help solve an age-old riddle of one of Saturn’s moons.  Iapetus has a strange appearance, one side is bright and the other is really dark, in a pattern that resembles the yin-yang symbol.  The astronomer Giovanni Cassini first spotted the moon in 1671, and years later figured out it has a dark side, now named Cassini Regio in his honor.

Saturn’s newest addition could explain how Cassini Regio came to be.  The ring is circling in the same direction as Phoebe, while Iapetus, the other rings and most of Saturn’s moons are all going the opposite way. According to the scientists, some of the dark and dusty material from the outer ring moves inward toward Iapetus, slamming into the icy moon.

The astronomers had a idea that Phoebe might be circling around in a belt of dust kicked up from its minor collisions with , a process similar to that around stars with dusty disks of planetary debris.  When the scientists took a first look at their Spitzer data, a band of dust jumped out.

The ring would be difficult to see with visible-light telescopes. Its particles are diffuse and may even extend beyond the bulk of the ring material all the way in to Saturn and all the way out to interplanetary space.  The relatively small numbers of particles in the ring wouldn’t reflect much visible light, especially out at Saturn where sunlight is weak.

Spitzer was able to sense the glow of the cool dust, which is only about 80 Kelvin (minus 316 degrees Fahrenheit). Cool objects shine with infrared, or thermal radiation; for example, even a cup of ice cream is blazing with infrared light.

These observations were made before Spitzer ran out of coolant in May and began its “warm” mission.

Venus can be found in the constellation Leo north of the star Regulus.

Finders chart for Venus in the constellation of Leo

Asteroid Juno forms a triangle with the stars 27 and 29 Piscium and Neptune can be found close by.

Finders Chart for Juno and Uranus

Finders chart for Jupiter and Neptune

Image Credit: NASA/JPL/Caltech

The image above combines seven frames taken by the navigation camera on Spirit on 28 April 2009 or the rovers 1.891st Martian day.  It covers a vista from south-southeast on the left to northeast on the right.

The site from which Spirit obtained this view has been informally named ‘Troy.’ Layers of differently hued soil uncovered by the sinking wheels became the subject of intense analysis by the instruments on Spirit’s robotic arm.

NASA, ESA, H. Hammel (Space Science Institute, Boulder, Colo.), and the Jupiter Impact Team

Just to prove that amateur astronomers can and do make valid contributions to observing important goings on in the Universe.  The impact on Jupiter was discovered by Australian amateur astronomer Anthony Wesley on Sunday 19 July 2009.  The spot was created by a small object either a comet or asteroid plunging into Jupiter’s atmosphere.   The last time this happened was on 16 July 1994, when comet Shoemaker-Levy 9  smashed into the gas giant and continued to bombard Jupiter until 22 July.

The Hubble team were lucky enough to be able to snap this image and at the time of the image the impact was twice the length of the United States.

The force of the impact on Jupiter is thought to be thousands of times more powerful than the suspected asteroid or comet that exploded over the Tunguska River Vally in Siberia during June 1908 and the object is thought to be the size of several football fields.

Credit: J.T. Clarke, G.E. Ballester (University of Michigan), and J.T. Trauger (Jet Propulsion Laboratory), and NASA

On the 16 July 1994 every one was watching Jupiter.  No, Arthur C Clarke’s story about the monolith hadn’t come true.  A comet was about to slam into the gas giant.

Comet Shoemaker-Levy 9 had been pulled into orbit around Jupiter.  It’s speculated that this happened during the 1970’s.  During it’s time in orbit around Jupiter, Comet Shoemaker-Levy 9 had been ripped apart by the formidable tidal forces of the planet.

No one was sure what would happen when the comet collided with Jupiter.  There were suggestions of huge seismic waves rippling across the planet or perhaps the comet debris would behave like meteors do in our own atmosphere.

The Galileo space probe was in the perfect place to observe as the drama unfolded.  As the first comet fragment struck the atmosphere of Jupiter, Galileo detected a fireball.  Its temperature peaked at 24,000°C (43,232°F) and created a plume of disturbed gas 1,900 miles (3,000km) in height.  Minutes later a huge dark spot came into view where the fragment had impacted.

The cometary fragments continued to bombard Jupiter until 22 July and the wounds on the planet were visible for months.

This dramatic event reminds us that Jupiters gravitational field is responsible for collecting many rogue bodies that wonder past it.  This means that there’s less chance that the Earth is going to be hit by something that could destroy all life.

ESA’s Venus Express has mapped Venus’ southern hemisphere in infrared.  The infromation provided by the new map suggestes that Venus may at one time have been more Earth like with plate tectonics and a liquid water ocean.

The map was compiled between May 2006 and December 2007 and consists of over a thousand individual images.  Because of Venus’ cloud cover it’s not possible to use normal cameras as they cannot image the surface.  To obtain the images Venus Express used a particular infrared wavelength to enable it to see through the clouds.

In the past radar systems have been used to provide high resolution maps of the surface of Venus.  ESA’s Venus Express is the first spacecraft to produce a map that hints at the chemical composition of the rocks whilst still in orbit.  The new data is consistant with the theory that the highland plateaus of Venus are ancient continents that were once surrounded by an ocean and were created by volcanic activity.

For further information go to ESA – Venus Express

Credits: NASA/JPL/Space Science Institute

Salty ice has been discovered on Saturn’s moon Enceladus.  The moon replenishes the ring with material from discharging jets and it’s thought that the moon could harbor a reservoir of liquid water, perhaps an ocean, beneath its surface.

The Cassini spacecraft discovered the water ice jets in 2005 on Enceladus.  These jets eject tiny ice grains and vapour, some of which escape the moon’s gravity and form Saturn’s outermost ring.  Cassini’s cosmic dust analyser has examined the composition of those grains and found salt within them.

The scientists working on Cassini’s cosmic dust detector  conclude that liquid water must be present because it is the only way to dissolve the significant amounts of minerals that would account for the levels of salt detected.  The process of sublimation, the mechanism by which vapour is released directly from solid ice in the crust, cannot account for the presence of salt.

The outermost ring particles are almost pure water ice, but nearly every time the dust analyser has checked for the composition, it has found at least some sodium within the particles.

However, researchers doing ground-based observations did not see sodium, an important salt component.  The ground-based observation team notes that the amount of sodium being expelled from Enceladus is actually less than observed around many other planetary bodies.  These scientists were looking for sodium in the plume vapour and could not see it in the expelled ice grains.  They argue that if the plume vapour does come from ocean water the evaporation must happen slowly deep underground rather than as a violent geyser erupting into space.

Determining the nature and origin of the plume material is a top priority for Cassini during its extended tour, called the Cassini Equinox Mission.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency.

You can find out more information at either ESA or NASA

Image Credit: NASA/JPL

This fantastic image was taken by the Voyager 2 probe back in August 1989.  The image shows Neptunes moon Triton.  To create the colours the images were taken through green, tiolet and ultraviolet filters.  In reality Triton does not appear blue, the filters create the illusion of this colour.  Triton is generally seen in tones of pink

You can discover more about the Voyager probes at NASA.
8cwfskjt9i