Aldebaran peeking out from beyond the Moon.
Credit: Roger Hutchinson
Sky & Telescope
Copyright © 2024
by Ralph F. Couey
Written Content Only
Visitors to this blog sometimes leave notes and comments, for which I am always grateful. Feedback is absolutely vital for any writer, whether good or...otherwise because it makes for a better writer from a technical standpoint, but also provides a space to be more aware and sensitive of the impact of my words.
I often write about things in nature, both here on this planet, but also throughout the universe. People have remarked on my "sense of wonder," and for that I plead guilty as charged. A recent post concerned an encounter I experienced with a preying mantis. I remember that day, and how I couldn't resist looking at it from very close range. I'm sure I made that poor critter nervous, especially when I carefully petted it. But all boys have a fascination with such things, and perhaps that part of me hasn't quite yet grown up.
I spend some evenings looking at the sky, toward those bright, enigmatic points of light in the sky. I marvel that many of those lights are stars that are tens of thousands of light years distant, and yet beyond my limited vision are billions of others stretching out billions of light years across a universe that continues to expand. The true size of our universe may be ultimately incalculable and beyond comprehension. The sheer vastness of it all remains an immense fascination for me, from the exquisitely micro to the eternally macro.
Renovations to our home were recently completed, one of which involved the creation of a new master suite. Our former bedroom is on the east side of the house, and just feet away lies our neighbor's abode. Now, we live on the west side of the house, facing the Waianae Mountains, actually the walls of an enormous and ancient volcano. The land slopes away from that side and we have a wide open view of the sky, and the gift of glorious sunsets every day.
One night, I was just drifting off to sleep when I saw a bright red-orange light appear from behind a drifting cloud. That I was able to see it sans spectacles was in itself remarkable. At first I assumed it was the giant planet Jupiter, a bright enough beacon in any sky. I put my specs back on and pulled up an astronomy app on my phone and aimed it in that direction. Turns out, Jupiter was still below the horizon and after some careful study, the light gained an identity. The star Aldebaran.
Aldebaran is an Arabic word meaning "follower." It is a type of star known as a red giant, and is located in the constellation of Taurus. It lies about 65 light years distant from earth. Interesting that the light that hit my bleary eyes that night left it's star when I was three years old, a journey almost as long as I am old.
Stars like our sun will spend billions of years fusing hydrogen into helium and other elements. Near the end of its life, the hydrogen will be exhausted, and the star will cool and grow, throwing off its outer layers. At the end of this process, all that will be left will be a small, intensely massive and bright white dwarf, which will then cool. Over trillions of years, it will become a black dwarf, a dark cinder floating through space. Aldebaran is on such a journey. Astronomers have calculated that Aldebaran is 44 times larger than our sun.
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Aldebaran's temperature is about 1,500 Kelvin, as compared to our star's 5,700 Kelvin and will continue to cool as it ages.
Scientists think Aldebaran has at least one planet, a Jupiter-like gas giant, only 11 times larger.
This star has been a familiar one to human cultures for thousands of years, and has a long list of names and stories. It's proximity to the cluster we call Pleiades actually gave its Arabic name, translated as "follower" as it seemed to pursue the seven sisters across the sky. The indigenous Mexican culture known as the Seris, the star provided light to the Pleiades, which they interpreted as seven women giving birth. In the Hindu culture it was known as Rohini, the favorite wife of the moon god, Chandra. In ancient Greece, Aldebaran was the torch bearer.
A close-up view.
Credit: Edison Urdaneta, Sky and Telescope Magazine
Pioneer 10, one of the deep space probes launched in the early 1970's along with Voyager's 1 and 2, will make a relatively close pass to Aldebaran in about 2 million years. Although long-dead as a spacecraft, Pioneer will for tens of millions of years be a monument, a sign of humanity's existence to curious alien eyes. And proof that they were not alone in the universe.
Aldebaran is the 14th brightest star in the northern hemisphere skies, and can be easily found by following the three belt stars of Orion the Hunter to the right to this bright orange sentinel. It's kinda cool to look at a star in the sky and know what it is.
The universe is enormous beyond words, and is always in motion and full of incredibly interesting things. To contemplate such depths opens the mind and the spirit to appreciate fully the beauty and majesty of creation. That night, I looked at a dying star and wondered if life had ever existed under it's once-benevolent gaze. That is, after all, the one unanswerable question of all living intelligence. Am I alone?
Some five billion years from now, our sun will exhaust it's hydrogen fuel and will begin it's long, slow death. Over about 1.5 billion years, it will swell out into the solar system, consuming the planets as it goes. Earth's oceans will boil away along with its atmosphere, though it will have been hostile to life for quite a while. About 60 million years later, earth will vanish into the sun's atmosphere.
In case you're REALLY interested, about a half a billion years before that happens, our Milky Way and the fast-approaching Andromeda galaxy will begin to merge. Given the uncertainty of climatic evolution on earth over billions of years, or our own penchant for self-destruction, it's not likely that anyone will be around to see that event.
But that would be a sky to look at!
Source: Uncredited
