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Alpha Centauri is the nearest star to our Earth and Sun.
Alpha Centauri is the nearest star to our Earth and Sun. Often, science fiction novels extol its ability to nurture new life or expound it as a destination for humankind. Paul Gilster in Centauri Dreams: Imagining and Planning Interstellar Exploration brings science and science fiction together in providing us with an up to date view on who's doing what to get people there, possibly starting as soon as this generation. He has only two exciting things to say about planning for the trip; it's here and it's now!
Researchers from the University of Michigan think that the current programs to search for extraterrestrial intelligence (SETI) might not be able to distinguish signals from the noise of nearby stars. They showed how an efficient message sent through radio waves is nearly indistinguishable from the ordinary thermal radiation coming from stars. If extraterrestrial civilizations have been transmitting for a long time, they'll probably have optimized their communications to save power, and so we won't recognize it when we hear it.
The early universe was much dustier than Astronomers were expecting, according to new data gathered by the Spitzer Space Telescope. This leads to the question, how did it get so dusty so early? Regular stars take billions of years before they star giving off large amounts of dust. But massive stars can form quickly and then explode as supernovae within 10 million years. The problem is that these explosions produce enormous amounts of hot dust, but very little cold dust, which is the kind found in the early Universe. So, the mystery continues.
Astronomers from the Harvard-Smithsonian Center for Astrophysics believe it's possible that our own Sun could have stolen some material from other stars billions of years ago. They came to this conclusion while trying to understand the orbit of Sedna, which takes 10,000 years to go around the Sun, in a highly elliptical orbit far beyond the Kuiper Belt. When our Sun was younger than 200 million years old, it could have swept past another star, disrupting the Kuiper Belt, and trading large objects (like Sedna) with each other.
Cassini took this image of the Encke Gap in Saturn's Rings. It's a small division 300 km (190 miles) wide near the outer edge of the rings. A tiny Moon called Pan orbits within this region, maintains the gap, and ties the particles into this knotted shape with its gravity. The image was taken while Cassini was 807,000 km (501,000 miles) away from Saturn.
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