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 Ο Γαλαξίας μας : Το κέντρο του : The centre of our Milky Way

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ΔημοσίευσηΘέμα: Ο Γαλαξίας μας : Το κέντρο του : The centre of our Milky Way   24.09.09 13:18



The center of our galaxy shines in greater detail than ever before, in this new composite image from NASA's Chandra X-Ray Observatory. The whole gamut of stellar evolution is here, from bright young stars to black holes.

The diffuse X-ray light suffusing the image comes from gas that has been heated by stellar explosions, massive young stars — and outflows powered by the supermassive blackhole at the heart of the galaxy, Sagittarius A.

Scientists believe Sagittarius A gave off giant X-ray flares 50 years and 300 years earlier.

(So when we finally visit the center of the galaxy searching for the mythical planet Sha-Ka-Ree in order to meet God and ask him why he wants a spaceship, we should time our visit to avoid one of those irregular X-ray bursts.)


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ΔημοσίευσηΘέμα: Απ: Ο Γαλαξίας μας : Το κέντρο του : The centre of our Milky Way   24.09.09 13:35

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ΔημοσίευσηΘέμα: Απ: Ο Γαλαξίας μας : Το κέντρο του : The centre of our Milky Way   01.06.10 13:53

The Galactic Center in Infrared from 2MASS



The center of our Galaxy is a busy place. In visible light, much of the Galactic Center is obscured by opaque dust.
In infrared light, however, dust glows more and obscures less, allowing nearly one million stars to be recorded in the above image.

The Galactic Center itself appears glowing on the lower left and is located about 30,000 light years away towards the constellation of Sagittarius.
The Galactic Plane of our Milky Way Galaxy, the plane in which the Sun orbits, is identifiable by the dark diagonal dust lane.

The absorbing dust grains are created in the atmospheres of cool red-giant stars and grow in molecular clouds.
The region directly surrounding the Galactic Center glows brightly in radio and high-energy radiation.

The Galactic Center is thought to house a large black hole.

Credit: 2MASS Project, U. Mass., IPAC/Caltech, NSF, NASA


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ΔημοσίευσηΘέμα: Απ: Ο Γαλαξίας μας : Το κέντρο του : The centre of our Milky Way   01.06.10 13:54

At the Center of the Milky Way



At the center of our Milky Way Galaxy lies a supermassive black hole. Once a controversial claim, this conclusion is now solidly based on 16 years of observations that map the orbits of 28 stars very near the galactic center.

Using European Southern Observatory telescopes and sophisticated near infrared cameras, astronomers patiently measured the positions of the stars over time, following one star, designated S2, through a complete orbit as it came within about 1 light-day of the center of the Milky Way.

Their results convincingly show that S2 is moving under the influence of the enormous gravity of a compact, unseen object -- a black hole with 4 million times the mass of the Sun. Their ability to track stars so close to the galactic center accurately measures the black hole's mass and also determines the distance to the center to be 27,000 light-years.

This deep, near-infrared image shows the crowded inner 3 light-years of the central Milky Way. Spectacular time-lapse animations of the stars orbiting within light-days of the galactic center can be found here.

Credit: ESO, Stefan Gillessen (MPE), F. Eisenhauer, S. Trippe, T. Alexander, R. Genzel, F. Martins, T. Ott


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Ο Γαλαξίας μας : Το κέντρο του : The centre of our Milky Way
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