The Winter Night Sky
Marla Mertz, Marion County Conservation, and Linette Bernard, Feathers & Ink
Have you seen a greenish shimmer in the northern sky on a cold winter’s night? That display of northern lights or aurora borealis happens when electrically charged electrons from the solar wind impact atoms in the earth’s upper atmosphere, the extra energy shows as light. This phenomenon happens around an area of the magnetic north pole.
The solar winds come from the sun at speeds about 1 million MPH – can you imagine how fast that is? In just 40 hours, these solar winds reach the earth and the winds follow the magnetic force made from the earth’s core and travel through the magnetosphere – a teardrop-shaped area filled with high energy electrical and magnetic fields.
As the winds bring the charged electrons to the upper atmosphere, these electrons collide with oxygen and nitrogen at altitudes (the vertical elevation above the earth's surface) of 20-200 miles above the surface of the earth.
These magnetic and electrical particles interact and react in ever-changing combinations and this is what helps the northern lights to dance, looking like wisps, curtains, pinwheels, and haloes. The website “How Stuff Works” helps us understand how the different colors of the northern lights are formed.
The color of the aurora depends on which atom is struck and the altitude of the meeting:
- Green – oxygen, up to 150 miles in altitude
- Red – oxygen, above 150 miles in altitude
- Blue – nitrogen, up to 60 miles in altitude
- Purple/violet – nitrogen, above 60 miles in altitude
Check these out, too!
What's in a name?
Where did the name aurora borealis come from? The aurora borealis gets its name from the mythical Roman goddess of the dawn, Aurora, and the Greek name for north wind, Boreas.
NOAA (National Oceanic and Atmospheric Administration) does track the probability of seeing a display of northern lights. Your local weather forecaster will likely let viewers know of high probability evenings to glimpse these northern lights.
While you’re outside watching for the northern lights (sometimes you only get very rare glimpses), check out the sky and stars above!
The stars above...
Have you ever just stopped in your tracks, looked up on a clear night and realized just how small we really are? Maybe, you stopped and wished upon a star. The night sky is magical, can be fierce, or filled with ultimate wonder.
The hardest thing about looking at the night sky is finding a place without the “light fog” or “light pollution.” Light fog, you ask - it’s all the lights we use within our cities and areas we live. The lights are directed downward and block our vision to the sky. If you are close to a hillside, public park, or maybe just a short drive to the country will make a trip well worth it. Anywhere you feel safe and away from lights will give you a grand view on a clear night.
There are websites and apps accessible to plan a night sky outing, but sometimes the impromptu invitation is well worth the wonderment to follow. Give it a try and then make a plan on things to find. Do you have to have a telescope? No. Do you have to have binoculars? No. The cold, crisp night sky is one you will never forget. The summer outings, laying on the ground and talking about the stars with your family is priceless.
Check out these links!
- Night Sky Planner
- Current night sky in Des Moines, Iowa (can display the night sky anytime and for any position on earth)
- Astronomy Clubs / Groups in Iowa
- Star Parties with the Des Moines Science Center of Iowa
- Des Moines Astronomical Society (Lists events, observatory, etc.)
I wish I may, I wish I might, wish upon a star tonight!
Big Dog, Dragon, Lyre, Twins are all names of constellations. Long ago, people saw patterns and pictures in the way the stars were arranged in the sky. Many of the names they gave these constellations are used today and others have also been named since ancient times. Here are a few:
- Big Dog (Canis Major)
- Dragon (Draco)
- Great Bear (Ursa Major)
- Hare (Lepus)
- The King (Cepheus)
- Little Bear (Ursa Minor)
- Lyre (Lyra)
- Orion the Hunter (Orion)
- The Queen (Cassiopeia)
- Scales (Libra)
- Swan (Cygnus)
- Twins (Gemini)
Many of the names are written in their Latin or Greek names and many books still use these names. Today, there is a total of 88 officially recognized patterns.
The Northern Circumpolar Constellations are always visible in the night sky of the Northern Hemisphere. These constellations are probably the most familiar to us. They include Ursa Major, the Big Bear that includes the Big Dipper and Ursa Minor, the Little Bear that includes the Little Dipper. See star chart at left.
These are some of the other Winter Constellations that can be viewed in our crisp cold night sky. Orion, the Hunter is said to be the most splendid constellation of all. See star chart right.
Download this Constellation and Stars activity and research page for you and your children.
GLOBE at Night (GaN) is a world wide citizen science project that anyone can participate in. The website has information about how to identify Orion and other constellations and use a magnitude chart. GaN asks people all over the world to go out and observe during specific dates (a 9 day period each month) and report the sky conditions and how visible the constellation was. People on every continent and even in the middle of the ocean contribute. You can also see past observations and reports about each year's project on the website.
Through different seasons, the skies reveal other constellations. Here is a link to show the winter constellations, as well as, the upcoming seasons.
Visit your local library and check for these books:
- Zoo in the Sky: A Book of Animal Constellations by Jacqueline Mitton
- The Everything Kids’ Astronomy Book: Blast into outer space with stellar facts, intergalactic trivia, and out-of-this-world puzzles by Kathi Wagner
- A Child’s Introduction to the Night Sky; The Story of the Stars, Planets and Constellations and How You Can Find Them in the Sky by Michael Driscoll
- National Audubon Society Pocket Guide to Constellations of the Northern Skies Pocket Guide by Mark Chartrand
- Night Sky Star Wheel by Sky Publishing
Winter halos and bows in our daytime skies
Cold winter weather may not be fun, but we can be treated to the beautiful sight of sundogs! During really cold weather, ice crystals drift and hang in the air at very low levels. These crystals are like prisms that bend and refract the light and two orbs of refracted sunlight appear on either side of the sun, at the same elevation of the sun. Sometimes the ice crystals are so randomly scattered that a halo around the sun can be seen.
Sundogs are normally seen around sunrise and sunset, but can occur at any time. Other terms that you may hear are “mock suns,” “phantom suns,” or parhelion. Photo at left used with permission R. Graham and the sundog below is from the Iowa DNR Facebook page!
Visit your local library for winter weather and general weather books!
- Snowflake Bentley by Jacqueline Briggs Martin
- Weather Words and What They Mean by Gail Gibbons
- A Drop Of Water: A Book of Science and Wonder by Walter Wick