STAR GAZER
THE INTERNATIONAL EDITION
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Horkheimer: Greetings, greetings fellow star gazers. When ever the constellation Orion the hunter is mentioned most people think of the three stars which make up his belt. But as wonderful as they are they really can't compare in wonder to one of the most incredible cosmic objects you'll ever see with the naked eye which masquerades as the middle star of the three stars which hang below Orion's belt and make up his sword. Let me show you.
O.K., we've got our skies set up for any night the next few weeks in early evening facing south where you will see winter's most famous constellation Orion the Hunter riding low above the horizon. Three evenly spaced stars in a row mark his famous belt, above them two bright stars mark his shoulders and below two more bright stars mark his knees. But if you look carefully just below his three belt stars you'll see three evenly spaced, much dimmer stars, which make up his sword. But no matter how sharp your eyesight, the middle "star" will always seem to look fuzzy, slightly out of focus.
And that's because it's not a star at all but something we call a nebula, a great cosmic cloud of gas and dust out of which brand new stars have recently been and are still being born. In fact this nebula, called the Orion Nebula, is a stellar womb, a birthplace and nursery of stars. And incredibly with a small inexpensive telescope you'll actually be able to see the four recently born stars which light up this gigantic gas cloud. They are arranged in the shape of a baseball diamond and are called the Trapezium. And they were born only one million years ago which compared to our Sun, which is 4 and a half billion years old, makes them true stellar infants.
Now although this nebula of Orion's looks tiny to the naked eye, in reality its size is mind boggling because there are at least one thousand unseen stars here hidden within this dense cloud. Plus there is enough material in this humongous cloud to produce over 10,000 stars the size of our Sun, wow! And think of this. When we measure distances to the stars we use the term 'light year', which is simply the number of miles light travels in a year, which is 6 trillion miles. The closest star to Earth other than our Sun is 4 1/3 light years away, which means it takes 4 1/3 years for its light to reach us.
The Orion Nebula however is so incredibly huge that we have to measure its size in light years. And it is a mind blowing 30 light years in diameter, which means that it takes 30 years for light to travel just from one end of it to the other. In fact it is so huge it would take 20,000 of our solar systems lined up end to end to reach from one edge of Orion's nebula to the other. Or to put it another way, if the distance from our Earth to the Sun were only one inch, the distance across the Orion Nebula would be 12 miles. Is that mind boggling or what? So get thee out to see this wonderful fuzzy middle "star" in the sword of Orion which astronomy writer Stephen James O'Meara says looks like, "Angel's breath against a frosted sky". See if you don't agree. Keep looking up!
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Horkheimer: Everyone loves Orion's bright stars but it is one of his dimmer stars that will blow you away. Face southeast and below Orion's three belt stars you'll see three dimmer stars, which make up his sword. But no matter how sharp your eyesight the middle star always seems to look fuzzy, out of focus. And that's because it isn't a star at all but a gigantic cosmic cloud of gas and dust where new stars are being born, a stellar nursery. We call it the Orion Nebula and there is enough material here to produce over ten thousand stars the size of our Sun. It is a humongous 30 light years wide, which means that if the distance from our Earth to the Sun were one inch the distance across the Orion Nebula would be 12 miles. How's that for a fuzzy little star? Keep looking up!
How did you like this episode?
Please give us your comments. (Click
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* This week's Sky At A Glance and
Planet Roundup from Sky & Telescope.Starry Night Deluxe was used to produce this episode
of Star Gazer
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