Anyone who even occasionally has gazed into the evening heavens in recent months has seen that bright “star” in the western sky. It’s so bright, that in the countryside it sometimes even casts a faint shadow.
That bright star is no star at all. It’s the planet Venus, 8,000 miles in diameter, named after the Roman goddess of love, and one of Earth’s planetary neighbors. Currently it’s about 105 million miles away.
Venus is so bright because its thick cloud cover completely shrouds the planet and acts like a giant celestial mirror, reflecting all kinds of sunlight. Planets produce no natural light of their own, so the only way we see them on Earth is from sunlight bouncing off them. Venus is the best reflector in our solar system.
Even though it’s so bright to the naked eye, Venus is a pretty dull sight through any telescope, no matter how big and fancy yours might be. All you really see is an ovalish white disk, and that’s it. There’s no way to see any of the Venusian surface. One thing Venus does that’s mildly entertaining is to go through phase shape changes, just like our moon. Sometimes Venus is oval shaped, as it is now, and sometimes it’s crescent shaped.
This week, though, Venus puts on a pretty good show as it celestially hugs the Pleiades, the brightest star cluster in the sky. Officially this “hug” is called a conjunction. Pleiades also is known as the Seven Little Sisters, because there are allegedly seven stars in the cluster that you can see with the naked eye. Most people, including yours truly, can see only six of the little shiners. It looks just like a tiny Big Dipper. In fact, I’ve heard some refer to it, in error, as the Little Dipper constellation. The actual Little Dipper (part of the Little Bear) is much larger.
For some time now Venus has been forging eastward among the background stars from night to night, and this week it makes its closest pass to the Seven Little Sisters. On Wednesday, Venus will be only 2.5 degrees to the upper left of the Pleiades. That’s slightly more than the width of two of your fingers held together at arm’s length.
Through a small telescope, or even through a pair of binoculars, I think you’ll like what you see. As I said before, Venus itself is pretty lousy eye candy, but the Pleiades are another story. Depending on how strong your optics are, you can see up to 100 stars in a sphere more than 80 trillion miles wide.
The Pleiades are much farther away than Venus, more than 400 light-years away. One light-year equals nearly 6 trillion miles. Like most open star clusters, the stars of the Pleiades are young, probably somewhere between 70 million and 100 million years old, which is young for a star. In fact, most of those stars were born just before the dinosaurs on Earth got wiped out. Our own star, the sun, is already middle-aged, over 5 billion years old.
Stars are born in large groups, out of large loose clouds of hydrogen gas called nebulae, and these young stellar families stay together for millions of years, until gravity from neighboring stars starts tearing the cosmic siblings apart.
One more thing – the Japanese refer to the Pleiades star cluster as “Subaru.” Sound familiar? Back in the 1950s seven small Japanese auto makers merged to form a larger company they called Subaru, after the seven stars that make up the Subaru star cluster. In fact, the early corporate logo for Subaru was an actual diagram of the cluster. The company has updated the logo over the years, but the present logo is still basically a star cluster. Look at any Subaru and you’ll see what I mean.
Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO radio in Minneapolis and author of the new book “Washington Starwatch,” available at bookstores and on his Web site, www.lynchandthestars.com.
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