Astronomer Robert H. Baker (1880-1962) once wrote of the Great Hunter or Celestial Warrior, Orion, that he shines "like a gigantic piece of celestial jewelry through the frosty winter air." Indeed, Orion is by far the most brilliant of the constellations and is visible from every inhabited part of the Earth.
As darkness descends, he clearly dominates the southeast sky. Three bright stars in line in the middle of a bright rectangle decorate Orions belt, which point northward to the clusters of the Hyades and Pleiades of Taurus, and southward to the Dog Star Sirius.
Within Orion we find two immense stars, Rigel and Betelgeuse, apparently at two entirely different periods in a stars existence.
In Rigel (the "Left Leg of the Giant"), we find a star apparently reaching the prime of its life. Its a true supergiant, a blazing white-hot star of intense brilliance and dazzling beauty. Located 773 light years away, Rigel's computed luminosity is roughly 57,000 times the brightness of our Sun.
able --> Betelgeuse ("The Armpit of the Giant") in contrast, shines with a cool, dull ruddy hue and is located 522 light years away. It is an irregular pulsating supergiant star, nearing the end of its life, expanding and contracting spasmodically.
Incredibly, Betelgeuse's diameter can vary between 550 to 920 times the diameter of our Sun.
Shadowy figure
As is also the case with the mighty Hercules, the figure of Orion has been associated in virtually all-ancient cultures with great national heroes, warriors, or demigods. Yet, in contrast to Hercules, who was credited with a detailed series of exploits, Orion seems to us a vague and shadowy figure.
The ancient mythological stories of Orion are so many and so confused that it is almost impossible to choose among all of them.
Even the origin of the name Orion is obscure, though some scholars have suggested a connection with the Greek "Arion," meaning simply warrior. All, however, agree that he was the mightiest hunter in the world and he is always pictured in the stars with his club upraised in his right hand. Hanging from his upraised left hand is the skin of a great lion he has killed and which he is brandishing in the face of Taurus, the Bull, who is charging down upon him.
The Great Orion Nebula
Below Orions three-star belt is undoubtedly one of the most wonderfully beautiful objects in the sky: the Great Orion Nebula. It appears to surround the middle star of a fainter trio of stars in a line that marks the hunters sword.
The nebula is invisible to the unaided eye, though the star itself appears a bit fuzzy. It can be resolved in good binoculars and small telescopes as a bright gray-green mist enveloping the star.
In larger telescopes it appears as a great glowing irregular cloud. A sort of auroral glow is induced in this nebula by fluorescence from the strong ultraviolet radiation of four hot stars entangled within it.
Edward Emerson Barnard (1857-1923), for many years an astronomer at Yerkes Observatory, once remarked that it reminded him of a great ghostly bat and that he always experienced a feeling of surprise when he saw it.
The Great Orion Nebula is a vast cloud of extremely tenuous glowing gas and dust, approximately 1,600 light years away and about 30 light years across (or more than 20,000 times the diameter of the entire solar system). Astrophysicists now believe that this nebulous stuff is a stellar incubator; the primeval chaos withiin which star formation is presently underway.
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