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Just How Earthlike is this New Planet?

When the recent discovery of a planet orbiting Gliese 876 was announced by astronomers, much of the interest focused on how “Earthlike” it is. So, just how like our home planet is it? Well… not very. For starters, the planet orbits only .021 the distance from the Earth to the Sun, and whips around its star once every 2 days. It has 6-8 times the mass of the Earth, so the gravity would be crushing for any potential life, not to mention the terrible radiation exposure from being so close to its parent star.

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Amalthea is Just a Pile of Icy Rubble

By studying data gathered by NASA’s Galileo spacecraft, researchers have come to the conclusion that Amalthea, one of Jupiter’s moons, is probably just a jumble of icy rubble, held together by gravity. Scientists originally believed it was made of rock, but Galileo helped to discover that its density is actually lower than water. It probably formed further out in the solar system, but was then captured into a stable orbit by Jupiter’s immense gravity.

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Did Life Arrive Before the Solar System Even Formed?

The theory of panspermia proposes that life really gets around, jumping fron planet to planet – or even from star to star. Life might be everywhere! Assuming this is true, how do single-celled bacteria make the journey through the vacuum of space? Easy, they use chunks of rock as space ships, in a process called lithopanspermia. And now, researchers from Princeton and the University of Michigan think that life carrying rocks might have been right there at the beginning of our solar system, keeping their tiny astronauts safe and sound, frozen in statis until the planets formed and the right conditions let them thaw out, stretch their proteins, and begin a process leading from microbe to mankind.

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Mini Solar System Around a Brown Dwarf

NASA’s Spitzer Space Telescope has found the dusty disc of planetary material surrounding an extremely low-mass brown dwarf. The failed star, called OTS 44, is only 15 times the mass of Jupiter, and is located 500 light-years away in the Chamaeleon constellation. Previously, the smallest brown dwarf known to have such a disc was twice as massive. Astronomers are now wondering if a habitable world could form around such a small, dim dwarf.

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Digging on Mars Won’t Be Easy

Because of the tremendous distance to Mars, human explorers will probably process local materials to get their air, fuel, and even building supplies. But extracting resources from the Red Planet is going to be hard, especially when the environment is so hostile. Scientists are studying how the dry Martian soil will likely behave in the low gravity and air pressure, to help engineers build equipment that can dig and move dirt. NASA’s upcoming Phoenix lander will help put some of this research to the test when it arrives on Mars in 2008; it will be digging trenches about a half-metre deep (20 inches).

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What’s Up This Week – Nov 8 – 14, 2004

Greetings fellow skywatchers! We’re in for more excitement this week as the Moon occults not one, not two, but three observable planets! But that’s not all the action, while we’re in a “planetary” frame of mind, we’ll also study two planetary nebulae, the M57 and M27, as well as seek out a “planetary” located inside a globular cluster. Other studies for both telescopes and binoculars will include instructions for “visiting with Vesta” as we explore one of our Solar System’s brightest asteroids. We’ll learn about easily observed variable stars and double your pleasure – double your fun as we explore two open clusters instead of just one! This week will also include a minor meteor shower and things for the Southern Hemisphere skywatchers to do. There are challenges here, as well as a bit of history and a lot of fun! So mark your calendars – because here’s “What’s Up”!

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Giant Infrared Space Observatory Considered by NASA

NASA is considering a new space-based telescope that would be the equivalent of a 40-metre (120 ft) observatory. The proposed Space Infrared Interferometric Telescope (SPIRIT) mission would consist of two infrared telescopes at opposite sides of a rail that could be positioned perfectly to combine their images into a single, giant telescope. SPIRIT is being considered as part of NASA’s Origins program, which is looking to answer fundamental questions about the beginning of the universe. If selected, it would launch in 2014.

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Our Solar System Could Be Special

Researchers from the UK believe that our Solar System could have formed differently from many other star systems, making places like our home much more rare in the Universe. After examining the 100 or so known extrasolar planetary systems, they found that they probably formed in a manner different from our own Solar System – in a way that’s hostile to the formation of life. Planets could form in several different ways, and how the Earth formed is actually quite rare. It will still be 5 more years or so before astronomers have equipment with the resolution to confirm this.

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Deeper Analysis of Phoebe Flyby

Scientists working with NASA’s Cassini spacecraft have stitched together photos taken by the spacecraft to build a complete picture of Phoebe, a moon of Saturn that the spacecraft passed on June 11. The tiny moon is likely an ancient collection of ice, rock and carbon-containing compounds similar to Pluto and Neptune’s moon Triton. Planetesimals like this could be very common in the outer reaches of the Solar System, as they were ejected during the early formation of the planets. Phoebe was probably captured early on by Saturn, perhaps 4 billion years ago.

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Look for Dust to Find New Earths

Instead of looking directly for Earth-sized planets, it might be easier to just try to find the ring of dust that is the fingerprint of terrestrial planet formation. This is according to a new computer model created by astronomers from the Smithsonian Center and Astrophysics and the University of Utah. Their model predicts that stars with disks will be a little brighter in the infrared spectrum than stars without disks; astronomers should be able to predict the size of its planets just from the brightness of its disk in infrared. The recently-launched Spitzer space telescope should be the perfect tool to measure these disks.