About The Author
D. R. Prescott has written a novel, a collection of short stories, a nonfiction book, a collection of essays, planetarium show/display scripts, two family histories, technical articles and business plans as well as written for and edited several newsletters.
 
Awards and published work include Writers' Journal, Long Story Short, Taj Mahal Review literary journal, The Orange County Register, Writer's Digest, and Writing.com and four books among other challenges.
 
As a former aerospace executive and planetarium program director, Prescott currently writes and explores life in Orange, California.
 
Picture to match DW in promo
"Sentience can be annoying."-DRP Abt. 1990
*Thumbsup*
 
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Since 2008, Prescott has been a regular contributor of
essays and short stories to
The Taj Mahal Review Literary Journal
Get your copies now at: http://tajmahalreview.com/
 
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Alpha Centauri and Beyond Radio Interview of Prescott
Books written. 
 
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O R D E R   T O D A Y !
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How Far Away Are Stars?
by D. R. Prescott



This is a common question at the planetarium. Establishing distances to objects as far away as stars is a gradual progression from the very precise to the reasonably accurate to the fairly accurate on through to the less accurate. Measurements within our solar system are very accurate. Distances to the nearest stars are reasonably accurate. Distances to stars at the other end of our galaxy are fairly accurate. Out to the edge of the universe, our measurements become less precise.

Let’s start with distances we know about. There is an inch, not much bigger than part of your thumb. The foot is 12 inches and you put 5,280 feet together and it becomes a mile. If you put 93 million miles together, you have one astronomical unit (1 AU). That’s the average distance from the Earth to our Sun.

Time also needs to be considered. Starting with one second, we can multiply that by 60 and get a minute; multiply that by 60 and we get an hour; multiply your answer by 24 and we have a day; multiply that by 365 and we have our year, the time in seconds that it takes our planet to orbit our sun, our nearest star.

Next, we need to know how fast light travels. Light travels at 186,280 miles per second. This is going to help make our numbers more manageable as we begin measuring the distances to stars because it is a long way and measuring in inches, feet or miles becomes tedious at best. How do we use this number? We multiply the number of seconds in a year by 186,280 miles/second. The answer is what is known as a light year, the distance light travels in one year, 5.9 trillion miles.

Now, we can talk about distances to the nearest stars without using really large numbers. The distance to the nearest star is 4.3 light years. That tells us that a photon of light takes 4.3 years to travel from our Sun to the nearest star system known as Alpha Centauri, a star system of three stars designated a Alpha Centauri A, B and Proxima. Sirius, also known as the Dog Star, is over 8 light years away; in miles that is 8 times 5.9 trillion miles.

Our Milky Way Galaxy is about 100,000 light years across. That means that the light from a star on the other side of our galaxy takes 100,000 years to reach us here on Earth. The light from a star as far away as across our galaxy is how it was 100,000 years ago, not as it is right now. In fact, it may have blown up in the last 100,000 years.

One of the examples, that we often use to illustrate the vast distances in space, is how fast we are traveling on our Earth at this very minute to make one orbit of the Sun in one year—66,600 miles per hour. If you went to Alpha Centauri in a spaceship that traveled as fast as our Earth does about the Sun, it would take you only 44,000 years to get there! If you traveled about as fast as we do on our freeways, 65 mph, it would take 44,000,000 years to make the same trip. Take your vitamins; it is a very long trip!

Space is huge. It is hard for human beings to comprehend its vastness. Its size is just one of its wonders and we are another part of all that wonder!

© Copyright 2010 D. R. Prescott (donprescott at Writing.Com). All rights reserved.
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' Copyright 2008 D. R. Prescott (UN: donprescott at Writing.Com). All rights reserved. D. R. Prescott has granted Writing.Com, its affiliates and syndicates non-exclusive rights to display this work. Questions or Comments? E-mail to prescottdc@sbcglobal.net
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