(ORDO NEWS) — The Saturn Nebula (NGC 7009) is a planetary nebula in the constellation Aquarius, 2300 light-years from Earth , that was discovered on September 7, 1782 by Sir William Herschel , an English astronomer, optician and composer of German origin.
This remarkable nebula got its name from the fact that, in early observations, it bore little resemblance to the planet Saturn and its almost edge-on ring system.
NGC 7009 has a bright central star (the cooling core of the star) that sits at the center of a dark cavity surrounded by an oval rim of dense blue-red gas.
The cavity and its rim are enclosed within an evenly distributed barrel-shaped greenish material that was once the star’s outer layers.
Farther back, along the nebula’s long axis, a pair of red “handles” appear, each connected to the ends of the cavity by a long greenish jet of material, much like hot gases escaping from a rifle barrel after a bullet.
As sun-like stars age, they become colder, darker, and greatly increase in size, turning into “red giants” . When a red giant sheds all of its outer layers, ultraviolet radiation from the “naked” hot stellar core causes the surrounding cloud of matter to glow: the object becomes a “planetary nebula”.
One of the longstanding astronomical mysteries is that scientists do not yet know how planetary nebulae get their complex shapes and strange symmetry.
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