Gliese 710.

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A view of a small part of the sky as if you were staring at a star (centre) approaching nearly head on, and then as it passes by and away again. The motion can be likened to what an observer standing beside a road would see looking at an approaching car, and then swinging around to continue to follow it as it moves away. As a result, the objects in the background – in this case distant stars – become blurred as you move quickly to maintain a visual on the passing object. The focus of this animation is the star known as Gliese 710. It will have a close encounter with our Sun in 1.3 million years, passing within the Oort Cloud reservoir of comets in the outskirts of our Solar System. The star is predicted to pass within about 2.3 trillion kilometres, the equivalent of about 16 000 Earth–Sun distances. The star’s motion is set against a background of other moving stars and the visualisation covers, very quickly, the timeframe from about 1.1–1.5 million years in the future. The size of

The Century that Defined Galaxy

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As the twentieth century dawned a debate raged over whether the Milky Way was the entire universe. The 1920s brought observations of spiral-nebulae that housed familiar but faint variable stars, and hence placed these nebulae much farther than anything else ever found. The Milky Way, apparently, is itself a spiral nebula seen from the inside. Soon interstellar dust was identified as the opaque material that blocks our view of distant spiral arms, confirming that our Sun was well away from the center. As the twentieth century closes, galaxies are seen forming across the universe, and our Milky Way is referred to as a spiral galaxy quite similar to NGC 1288, as pictured above.



Credit: FORS1, 8.2-meter VLT, ESO 
Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA/ GSFC
& Michigan Tech. U.
Tomorrow's picture: The Millennium that Defined Earth 

 Fonte: Nasa