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Can You See the Light Part Three

December 14, 2015
By Robert and Libby Strong and Richard Pollack - SMART Science , OVParent

You are now aware that light pollution exists and is a problem - see Part One in the October OV Parent Magazine. Additionally, you know how to tell the difference between good, bad and ugly outdoor lighting, which we covered in Part Two in November.

You also are now aware that with even darker skies West Virginia can benefit from a nearly untapped type of tourism - Dark Sky Tourism (also in Part Two). Many people in light polluted cities in the eastern U.S. are within a one-day drive of West Virginia. If West Virginia truly made a statewide effort to improve its already dark skies and advertised this, many Dark Sky tourists living in these nearby cities would consider planning a vacation in West Virginia just to experience a real dark night and the Milky Way!

Did you know many people along the Eastern Seaboard have never seen a dark sky filled with stars, and most people from large cities have never seen the Milky Way? In many nations around the world, young people are moving to brightly illuminated cities to find work. For the first time in the history of our planet, there are fewer people who have seen the Milky Way and more people who have never seen the Milky Way, and it is getting worse as the cities grow.

Article Photos

For most of us here in West Virginia, a clear moonless night means we easily can see at least a thousand stars against the inky darkness in a single glance into our dark skies.

But why do we care to see the Milky Way? What is it really?

The Milky Way is actually our home galaxy. It is of the barred spiral type. You can find spiral galaxy pictures in any astronomy book or website about galaxies. The Milky Way consists of a vast collection of somewhere around 350 billion (350,000,000,000) stars. And we see it from within it, because the sun, our day star is but a single star inside the Milky Way.

The Milky Way, the band of luminous glow we see, also shows us the shape of our galaxy. The Milky Way is disk shaped. Looking along the width of this disk of stars from the inside, we see more stars. The Milky Way's glow is the sum of all the faint light from untold millions of stars in the line of sight along any path into this width of this disk of stars.

Looking away from the Milky Way, there are fewer stars in our line of sight as we are seeing the stars only in the relatively thin region as we look along the thickness of the disk of stars, and therefore we see less to none of a Milky Way glow.

These wondrous views from a dark sky are becoming rarer with each new street light, each outdoor flood light and every vanity lighting of wall, tree and shrub.

Activity: Scale Modeling The Milky Way Galaxy

All you need for this activity is a meter stick, some definitions and a little imagination.

Large distances and sizes in space are measured in light years. A light year is the distance light will travel in one year, or about 9.46 trillion kilometers (9,460,000,000,000 km) or about 5.88 trillion miles.

In this model, 1 centimeter (there are 100 of these divisions of the meter stick) equals 1,000 light years (this is 1 to the sextillion scale).

If you do not have a meter stick at home, ask your teacher if you can use one of the meter sticks in your classroom at school and do this for the whole class.

Hold the meter stick at the halfway or 50 cm point and make a fist. The meter stick length represents the diameter of the Milky Way Galaxy at 100,000 light years. Your fist represents the galactic bulge of our galaxy.

You cannot see it, but deep down inside your fist at the center of our galaxy is a super massive black hole over 4 million times the mass of the Sun!

The Sun and the Earth are located 27,000 light years from the bulge - 27 centimeters from the center of your fist or 23 centimeters from either end of the meter stick.

Gently spin the meter stick (your fist is the center of spin) while holding it. This action sweeps out the disk shape of the Milky Way galaxy. Note: the thickness of our galaxy is the thickness of the meter stick or about 1 cm (1,000 light years) and it takes 240 million (240,000,000) years to turn around once!

That's why people NEED to see the Milky Way - it is our home galaxy, it is where we live. To see the Milky Way and understand what it is does not make us smaller, it makes us a part of something vastly bigger than our small selves. Seeing the Milky Way reminds us that we are a part of the universe!

How You Can Help

Many of you may have asked, "What can I, my friends and my family do to fix the light pollution problem?"

How do you fix bad or ugly outdoor lighting and turn them into good outdoor lighting that minimizes light pollution and its effects on our nighttime sky?

The first goal in fixing the problem of light pollution will be to start a conversation with you neighbors, friends and family. Make them aware of what light pollution is and how its absence here in West Virginia will create a new type of tourism.

Remember the best way to solve light pollution is to limit outdoor lighting to what is actually needed, when it is needed and where it is needed.

Good lighting saves money, generates tourism and allows us to experience the nighttime sky that is our heritage here in "Wild and Wonderful" West Virginia.

Libby and Robert Strong and Richard Pollack work with the SMART-Center, a hands-on science outreach and education organization in the northern Ohio Valley, the headquarters of which is located at the SMART Centre Market, 30 22nd St., Wheeling.



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