When Cassini passed directly behind Saturn, the Ringed Planet obscured the Sun, and gave the spacecraft a unique view of the delicate ring structure. These observations have shown scientists that the planet’s moon system is probably generating new rings. These moons are pounded by micrometeorites over time, but they don’t have the gravity to hang onto the material. Over time, this material floats away from the moons and collects into the diffuse rings we see today.
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Red Spot Jr. is Getting Stronger
Jupiter’s newly formed Red Spot Jr. is increasing in strength, according to new observations from the Hubble Space Telescope. These latest measurements clock its windspeeds at 640 kph (400 mph); almost double the speeds recorded by the Voyager spacecraft when it observed one of the spot’s parent storms in 1979. The increased windspeed probably dredged up deeper material from the planet, changing its colour from white to red, similar to the Great Red Spot.
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Super Earths Emerge From Snowy Conditions
Many extrasolar planets have been discovered circling other stars, a few of which are 5-15 times the mass of the Earth, and thought to be solid like our planet. Astronomers were surprised to find these planets orbiting small, cooler red dwarf stars. Researchers believe these “super Earths” form in the chilly halo of snow, ice and frozen gasses that collect around red stars as they cool. There probably isn’t enough solid material to form rocky planets much larger than Mercury in the star’s habitable zone.
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Something Recently Collided Into Saturn’s Rings
Astronomers have found evidence that a comet or asteroid might have recently collided with Saturn’s rings. New images from Cassini show a region of Saturn’s D ring that seems to have a series of smaller ringlets outside it. This structure was originally discovered by the Hubble Space Telescope more than 10 years ago, but spacing between the ringlets has decreased by half since then; from 60 km down to 30 km.
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Gardening for the Moon
When astronauts return to the Moon and visit Mars in the coming decades, they’ll want to bring as little as possible from Earth. That means living off the land wherever possible. Wouldn’t it be great if they could grow their own food? Researchers from Texas A&M University have grown lettuce in special cylinders that provide the plants everything they need to grow – but in a very low pressure environment.
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Aldebaran Slips Behind the Rings
In this Cassini image, the bright giant red star Aldebaran slips behind Saturn’s rings. This kind of view is known as a stellar occultation, and it gives scientists an opportunity to study the rings themselves by how the block and distort light from the star. The star’s light fluctuates as it passes behind various regions of the rings, providing details on ring thickness and composition.
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Podcast: The Big Bang and Cosmic Microwave Background
As a tribute to John Mather and George Smoot, the two leaders of the Cosmic Microwave Background Explorer (COBE) satellite science team, and winners of this year’s Nobel Prize for Physics, we head back to the beginning of everything – the Big Bang. Follow as we trace the Big Bang’s discovery, and one of the most important lines of evidence: the cosmic microwave background radiation which was predicted by theory and then discovered by accident.
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What’s Up this Week: October 9 – October 15, 2006
Greetings, fellow SkyWatchers! As the week begins, keep an eye out for members of the Draconid meteor shower as we begin a in-depth look at globular cluster – M15. There will be plenty to explore, so get out your optics and head for the stars, because…
Here’s what’s up!
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Hubble Examines the Closest Known Extrasolar Planet
The Hubble Space Telescope turned its gaze towards a relatively nearby Jupiter-sized world recently. The planet orbits the Sun-like star Epsilon Eridani, which is located only 10.5 light-years away. This makes the planet so close that it could be directly observable by Hubble, and large ground-based observatories. The best opportunity will come in 2007, when the planet makes its closest approach to its parent star, and the reflected light should make it observable with our best instruments.
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Survey of Nearby Black Holes
Ever wonder how many black holes are nearby? Well, NASA has gone and counted them for you. According to data gathered by NASA’s Swift satellite, there are about 200 supermassive black holes within about 400 million light-years of the Earth. Swift’s first job is to scan the skies for gamma ray bursts, but during downtime, the spacecraft hunts for objects that emit X-rays. And supermassive black holes are one of the most powerful sources of X-rays out there.
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