Pixel Tracker

Thursday, February 21 , 2019, 6:44 pm | Partly Cloudy 50º

 
 
 
 
Astronomy

Dennis Mammana: Big Dipper Through the Millennia

The Big Dipper is an optical illusion. Click to view larger
The Big Dipper is an optical illusion. (Creators.com illustration)

Years of living and working have taught me many lessons. But one lesson seems to be truer than most: Whatever is temporary is permanent, and whatever is permanent is temporary.

This applies everywhere — buildings, governments, relationships, etc. Things we’re convinced are everlasting are almost always destined to change. And things we’re told will be only temporary — taxes, detours, visits from in-laws — well, they often turn out to be permanent!

Even the heavens, which we humans perceive as eternal and unchanging, are only temporary.

While we often refer to the stars and constellations as being fixed — especially when we watch the moon and planets drift gracefully in front of them — they are actually moving in seemingly random directions at speeds of many miles per second.

Since the stars reside trillions of miles away, we’re not able to notice their movements over short periods of time, so we perceive them as fixed. If we are patient, however, we can see reality.

Take, for example, the stars of the Big Dipper, which appear high in the northern sky at this time of year. To most of us in the northern hemisphere, this celestial icon is one of the first star groupings we learn to recognize. Every scout has used it to locate the North Star and use it to navigate during the night.

The Big Dipper’s shape has been represented by various cultures throughout history, as a bear followed by three warriors, a wagon, a plow and (in Chinese culture) the government itself.

Its shape, sometimes called the “drinking gourd,” even served in song to inspire pre-Civil War slaves to flee to the North for freedom. We’ve come to recognize the seven stars of its bowl and its long, curved handle as a permanent sight.

But what we see as the Big Dipper is not real. It’s not a solid structure; it’s purely an optical illusion that occurs because of where we live in our galactic neighborhood.

If we could fly freely through space and travel to the other side of those stars, though, our perception of the Dipper would change as we travel.

The dipper shape is fluid over time as well. Its five central stars are stellar siblings. They were born from the same interstellar cloud some 500 million years ago, and still travel together at remarkable speeds.

But seeing this movement is another matter altogether. If we could accelerate time and watch this star grouping for tens of thousands of years, we would begin to see the Dipper’s shape change as its stars move through space.

A hundred thousand years ago, the first Homo sapiens in the Middle East may have recognized this stellar collection as a celestial fishhook, rather than a dipper. And our descendants a hundred millennia in the future will also see the shape of a dipper, but one that is distorted and reversed from what we see today.

So the next time you think about heading outdoors to enjoy stars and constellations, don’t put it off too long. Remember: Whatever is temporary is permanent, and whatever is permanent is temporary!

Dennis Mammana is an astronomy writer, author, lecturer and photographer working from under the clear dark skies of the Anza-Borrego Desert in the San Diego County backcountry. Contact him at [email protected] and follow him on Twitter: @dennismammana. The opinions expressed are his own.

Support Noozhawk Today

You are an important ally in our mission to deliver clear, objective, high-quality professional news reporting for Santa Barbara, Goleta and the rest of Santa Barbara County. Join the Hawks Club today to help keep Noozhawk soaring.

We offer four membership levels: $5 a month, $10 a month, $25 a month or $1 a week. Payments can be made using a credit card, Apple Pay or Google Pay, or click here for information on recurring credit-card payments and a mailing address for checks.

Thank you for your vital support.

Become a Noozhawk Supporter

First name
Last name
Email
Select your monthly membership
Or choose an annual membership
×

Payment Information

Membership Subscription

You are enrolling in . Thank you for joining the Hawks Club.

Payment Method

Pay by Credit Card:

Mastercard, Visa, American Express, Discover
One click only, please!

Pay with Apple Pay or Google Pay:

Noozhawk partners with Stripe to provide secure invoicing and payments processing.
You may cancel your membership at any time by sending an email to .(JavaScript must be enabled to view this email address).

  • Ask
  • Vote
  • Investigate
  • Answer

Noozhawk Asks: What’s Your Question?

Welcome to Noozhawk Asks, a new feature in which you ask the questions, you help decide what Noozhawk investigates, and you work with us to find the answers.

Here’s how it works: You share your questions with us in the nearby box. In some cases, we may work with you to find the answers. In others, we may ask you to vote on your top choices to help us narrow the scope. And we’ll be regularly asking you for your feedback on a specific issue or topic.

We also expect to work together with the reader who asked the winning questions to find the answer together. Noozhawk’s objective is to come at questions from a place of curiosity and openness, and we believe a transparent collaboration is the key to achieve it.

The results of our investigation will be published here in this Noozhawk Asks section. Once or twice a month, we plan to do a review of what was asked and answered.

Thanks for asking!

Click Here to Get Started >

Reader Comments

Noozhawk is no longer accepting reader comments on our articles. Click here for the announcement. Readers are instead invited to submit letters to the editor by emailing them to [email protected]. Please provide your full name and community, as well as contact information for verification purposes only.

Meet Your Realtor Sponsored by Village Properties

Photo of Patricia Griffin
Patricia Griffin
"I am very hands on and feel that each transaction is special and different. My clients goals are foremost in what I do to bring about a successful transaction and I maintain relationships for many years."

Full Profile >

Daily Noozhawk

Subscribe to Noozhawk's A.M. Report, our free e-Bulletin sent out every day at 4:15 a.m. with Noozhawk's top stories, hand-picked by the editors.

Sign Up Now >