Orion's Great Stellar Nursery


Last updated 2/15/2024 at 12:31pm

The elements in our bodies now were once part of stars like the ones in the Trapezium.

In his 1926 book "The Universe of Stars," the American astronomer Harlow Shapley wrote: "We are therefore made out of star stuff ... we feed upon sunbeams, we are kept warm by the radiation of the sun and we are made out of the same materials that constitute the stars."

Since then, others have made similar references to "star stuff" and "stardust", including astronomer Carl Sagan and folk singer Joni Mitchell. It's all quite poetic, but what does it mean?

It means that the materials out of which we are composed – the carbon in our DNA, the iron in our blood, the calcium in our bones – were forged ages ago within distant stars and blasted into space during those stars' dying moments.

After drifting through our galaxy for eons, this chemically rich stellar ash merged with existing interstellar clouds where it triggered the birth of new stars and planetary systems. And, in at least one place – right here on Earth – formed life itself.

It's not tough to find places where similar activity occurs today. We need only to look toward the brilliant constellation Orion, now appearing in our evening sky.

In ancient mythology, Orion represents a hunter, with its three equally bright stars appearing in a straight line forming his "belt." Just to their south hang several faint stars that outline his "sword."

One of these stars may appear rather fuzzy to you. Aim binoculars or a small telescope in its direction and you'll see one of the most marvelous sights in all the heavens. It's known to astronomers as M42: the Great Orion Nebula.

M42 is a colossal cloud of interstellar gas and dust that lies nearly 9,000 trillion miles, or 1,500 light-years, away and is illuminated from within by the light of brilliant young stars. Today we know it as one of the most prolific star- and planet-birthing regions in our galactic neighborhood – a veritable stellar nursery.

With even a small backyard telescope under a dark sky, you'll see the delicate structure of this stellar birthplace and, near its center, a tightly packed cluster of four bright stars (the "Trapezium") that illuminate the cloud from within.

These are young stars, only about 300,000 years old. Now, while that may sound ancient to us humans, to a star it's quite a short time. Since the stars of the Trapezium will most likely live for 10 million years or so, 300,000 years to them is equivalent to about three years to a human. And, amazingly, you can see these "toddler" stars with nothing more than a small backyard telescope!

Larger instruments show us much more. Recently, astronomers using the James Webb Space Telescope have found dozens of planet-sized bodies drifting among these stars. Whether the star stuff that produced these bodies will also give birth to life remains to be seen.

In the meantime, just gazing up at Orion and its great nebula reminds us that the stars are our ancestors, for it is they that have forged the raw materials – the star stuff – to make all life possible. And that's a pretty remarkable concept to ponder while gazing into a starry night sky.

Visit Dennis Mammana at dennismammana.com.

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