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

Fractal Interstellar Dust Up-Close

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Explanation: Our universe is a very dusty place. Dust usually shows its presence by blocking out light emitted from stars or nebulae behind it, sometimes creating the illusion of a horse's head or a sombrero hat. But nobody really knows what a typical interstellar dust grain looks like. By studying how dust absorbs, emits, and reflects light, astronomers do know that interstellar dust is much different than the cell and lint based dust found around a typical house. Interstellar dust grains are composed mostly of carbon, silicon, and oxygen and are usually less than about 1/1000 of a millimeter across. Recent work indicates that most dust grains are not spherical. The above picture shows the result of a fractal adhesion model for dust grains involving random conglomerates of spherical compounds of different properties, here artificially highlighted by different colors.


Credit & Copyright: E. L. Wright (UCLA)
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: A Polar Ring Galaxy

 Fonte: Nasa