One of the biggest brightest clusters of stars in the sky is 47 Tucanae, located in the southern constellation of the Toucan. Located about 16,000 light years away, this globular cluster contains a million times the mass of our Sun, and measures 120 light years across. The stars in the cluster are so dense, they average only 1/10th a light year apart; approximately the size of the Solar System. This photograph was taken using the European Southern Observatory’s Very Large Telescope.
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Highway of Stars in the Sky
A pair of astronomers from the US and Italy have discovered a stream of stars moving through the sky at 230 km/second (500,000 mph). The stream has been found to extend 30,000 light years across the sky, but it could extend even further. The discoverers believe the stream is all the remains of a gigantic star cluster that was torn apart by the Milky Way’s gravity. If correct, there could be hundreds more of these streams circling our galaxy.
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Earth’s Second Moon is About to Leave Us
In addition to the Moon, the Earth also has a collection of co-orbital satellites. These are really nothing more than asteroids briefly captured by the Earth’s gravity. Instead of orbiting the Earth, they take corkscrew paths around our planet, eventually escaping back into the Solar System. One asteroid, 2003 YN107, has been traveling with us since 1999, and now it’s about to depart, building up enough speed to escape the Earth’s gravity.
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Titan Behind Saturn and the Rings
This photograph shows Titan partly obscured behind Saturn and its rings. The image was taken from above the ringplane, and shows the side of the planet unlit by the Sun. Cassini captured this view on May 10, 2006 at a distance of approximately 2.9 million kilometers (1.8 million miles) from Saturn.
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Supernovae Generated the Universe’s Early Dust
As early as 700 million years after the Big Bang, galaxies were already filled with cosmic dust. But where did it come from? There are two known sources of dust: old stars and supernovae. Astronomers studied nearby supernovae SN 2003gd using the Spitzer space telescope, and found that it had produced tremendous amounts of dust. Since there were many supernovae in the early Universe, they could be the source of all this dust.
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Ancient Life Survived Snowball Earth
Approximately 2.3 billion years ago, bacterial life had generated enough oxygen to make the air breathable for larger creatures. Unfortunately, this was also a stage when our planet went through one of its “Snowball Earth” phases, when the entire planet was encased in kilometer-thick snow and ice. Scientists have found evidence that multi-celled eukaryotes – our distant ancestors – were thriving on Earth, before and after the big chill. While most of the planet was covered, there were probably pockets that were ice free, where islands of life could survive.
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Hubble View of NGC 5866
The Hubble Space Telescope captured this magnificent view of disk galaxy NGC 5866, seen nearly edge on from our vantage point. The galaxy’s dark dust lane is clearly visible, and it appears to be slightly warped, compared to the disk of starlight. This indicates that it probably brushed past another galaxy in the distant past. NGC 5866 is located in the constellation Draco, approximately 44 million light-years away; it’s similar in mass to the Milky Way, but only two-thirds the diameter.
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How Super Earths Might Form
Although our Solar System only contains a “regular Earth”, astronomers predict that other systems could contain “super Earths”; rocky planets with several times the mass of our planet. A new theory predicts that these planets should be most commonly found orbiting red dwarf stars. As red dwarf stars have less mass, they’re unable to hang onto the lighter gas that go onto form gas giants. The remaining heavier elements have time to form very massive terrestrial planets.
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Large Amounts of Carbon Around a Distant Star
Astronomers have discovered a solar system with an unusually high amount of carbon; it could be at the stage where the rocky planets are forming. The system, called Beta Pictoris, is located 63 light-years from Earth and has a central star with twice the mass of our Sun. NASA’s FUSE (Far Ultraviolet Spectroscopic Explorer) and Hubble observed that gas around the star matches the composition of our own Solar System quite well. The stars intense radiation should be driving this gas away, but ionized carbon atoms are acting as a brake to keep it contained.
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First Images From Cloudsat
Meteorologists and scientists have a new tool at their disposal; NASA’s new CloudSat satellite, which is capable of building 3-D images of clouds. CloudSat launched on April 28 from Vandenberg Air Force Base with two other satellites. After several weeks of testing, mission managers tested its Cloud-Profiling Radar system in May. Its first image was a slice of atmosphere above the North Sea in the Atlantic Ocean. CloudSat’s radar system is 1,000 times more powerful than typical weather radar.
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