Background for Teachers
Stars Over Texas
The blacker the better!
This topic gives you a great chance to introduce your students to the discussion of light pollution. For most children this will be a new topic.
Texas Co-op Power ran a great article by Camille Wheeler in its December 2010 issue about the topic of light pollution. Check it out here: http://www.texascooppower.com/texas-stories/nature-outdoors/light-pollution.
In the article, Wheeler notes that outdoor lighting seems to be one of the major causes in Texas of our light pollution. Further, the article implies that if there was such a thing as "good" light pollution and "bad" light pollution that outdoor lighting might be considered "good" light pollution because it's the sort we can most easily do something about.
Ask your children to discuss ways that light is used in their own lives. Ask them, "Does all outdoor lighting that we use, indeed need to be?" In general, ask your children to reflect on their "lighted" world.
Easily help your children understand the effects of light pollution by asking them to tell you why they turn the lights off before showing a film in a theatre. Ask them how different they think the viewing experience might be if the lights stayed on. In fact, next time you show a film, use the experience to revisit the topic of light pollution.
If your classroom has windows you can even make the room darker by degrees and show that varying amounts of light can effect the quality of the image that children will see on the screen. Help them connect this to the way the extra light we've created on Earth has "polluted" the image of what we can see in the heavens above.
The sky appears differently depending upon the time of the year
The Student Resources Page tells your kiddos, "As Earth orbits around the sun, the night side of our planet faces the sun at different times of the year. That means the sky appears differently depending upon what time of the year you look at it."
This gives you a great opportunity to review why we have seasons and to revisit the topic of equinoxes and solstices.
Remind the children that the seasons are opposite above and below the equator. For example, when it's springtime above the equator, it's autumn below the equator. Thus, the stars that we see in the springtime will be the stars that those below the equator will see in the fall. Of course, this is oversimplifying, as the closer you are to the equator the smaller the seasonal variations and night-sky shifts will appear to you.
Since Texas lies relatively close to the equator, our changes will be small compared to many other places north of the equator. The more dramatic and noticeable differences occur nearest the poles.
West Texas has the darkest skies in the continental U.S.!
Children are used to the traditional image of the outline of the United States and you can tell them that, basically, the U.S. that they're used to picturing in their minds is the continental U.S.
But remind them that Alaska and Hawaii are also members of our country. Then, for a little trivia (you know how kids love that! They'll think they got you off the subject at hand!), teach the children that Alaska and Hawaii were the last two states to join the union. Alaska was the 49th state and Hawaii the fiftieth. Both became part of the United States of America the same year, in 1959, Alaska in January and Hawaii in August.
Make sure the children know where Texas lies within the continental United States. Then, ask them to identify where, specifically, west Texas lies within Texas.
Discuss the fact that the terrain in west Texas is very dry and the lack of water is part of the reason this area has remained less populated than other regions of our state. Discuss the mountains that populate this region and how that may have kept folks from being able to travel as easily here when they were settling Texas. Ask them to think about what all of this might have to do with light pollution and having the darkest skies in the continental U.S.
Explain that having the University of Texas McDonald Observatory in this region has given us an incentive to keep light pollution in this area to a minimum. Ask them why they think that might be.
Today we have 88 official named constellations, determined so in the early part of the 20th century by the International Astronomical Union (IAU). Technically, constellations are an area of the sky. Each of the 88 areas comes up against the boundary of another of the 88 areas. In that way, every point in the sky lies within one of the 88 areas, or 88 constellations.
Many folks mix the official definition of a constellation up with the colloquial version, probably because so much more history, lore, and well, truthfully, fun, revolves around those stars that seem to form pictures of beasts and hunters and other fruits of less scientific imaginations.
But those pictures actually are what we call "asterisms." Today many of the 88 official constellations use the traditional names of the constellations of yesteryear, and somewhere within their larger area they contain the original asterism responsible for their name.
This list of constellations from the McDonald Observatory StarDate site is a wonderful resource: http://stardate.org/nightsky/constellations
The Milky Way
Think of the Milky Way Galaxy as a fried egg: the middle bulges as a yolk would and the edges flatten out as the whites would. However, the "whites" would be spirals, almost like a pinwheel since ours is a spiral galaxy.
The Milky Way is part of a collection of 35 galaxies known as "The Local Group." The Local Group moves through space as one unit, bound together by gravity. Learn more here: http://stardate.org/astro-guide/btss/galaxies/local_group.
Big Dipper & Little Dipper
The Big and Little Dipper are often mistakenly called constellations, but the fact is that they belong, respectively, to the constellations Ursa Major and Ursa Minor. If not constellations, then what are the dippers? Asterisms, or star patterns.
This very entertaining episode of StarDate tells about the Greek mythology surrounding the Big and Little Dipper: http://stardate.org/radio/program/2010-04-03. Listen first, and then decide if you want to share with your children. It's a neat story that explains how the two "bears" that host the dippers came to live in the sky.
This educational StarDate program will also provide you with some more scientific information about the Little Dipper: http://stardate.org/radio/program/2010-04-04 .
The inner planets are smaller and denser than the outer planets. You might hear them referred to as the "rock" planets or the "terrestrial" planets because they are composed mostly of solids (silicates and metals). These four planets also have either no moons or few moons orbiting them.
Remind your children of the three states of matter when you discuss the significance of water on Earth in its liquid form and how important a role that plays in sustaining life.
The outer planets lack the solidity of the inner planets and thus have come to be called the "gas giants." Their gaseous nature gives them rings made of particles of ice and rock (some, like Saturn, much more than others), while the inner planets have no rings at all.
Listen to this great StarDate radio show about Saturn: http://stardate.org/radio/program/voyager-1-saturn. (This is too advanced for your students, but it will give you some great background information to share with them.)
One of the most interesting things to know about Uranus is that its poles are completely different than any of the other planets in our solar system. A collision with another heavenly body caused the planet to tilt sideways, giving it east-west pole. Each pole will receive 42 years of alternating darkness and sunlight during the planet's 84-year-long orbit around the sun.
This fascinating episode of StarDate discusses some of the changes that Uranus is undergoing: http://stardate.org/radio/program/uranus
Kids will probably know them as "shooting stars" and "falling stars," but those intense streaks of light are really called "meteors." Small bits of debris crashing through Earth's atmosphere at thousands of miles per hour create meteors. The friction of the atmosphere causes the particles of dust and interplanetary debris to ignite 30 to 80 miles above us.
Often these bits of debris come from comets. As Earth travels through the stream of debris left behind by a comet's orbit, what's been left behind might find its way into our atmosphere as a meteor shower.
Meteor showers get their names from the constellations from which they seem to fall. For example, the Leonid meteor shower that we can see from our Texas skies each November appears to fall from the constellation Leo. Likewise, the Perseid meteor shower gets its name because its meteors seem to originate from the constellation Perseus.
McDonald Observatory has created a wonderful list of 2011 meteor showers you can look forward to watching. May we suggest putting this list up in your classroom so that your children can remember, too? http://stardate.org/nightsky/meteors.
As meteors crash through the atmosphere, almost all are destroyed. Those that survive are called, "meteorites." When geologists carbon date meteorites they find most of them to be nearly 4.6 billion years old, which is older than the less than 4 billion years old for the oldest of Earth's rocks.
Like a little mystery?
If so, you'll definitely want to check out these two links:
- This 2009 video shot by an Austin news cameraman shows an unidentified fire ball. Also, be sure to read the interesting info on this site about a West Texas "strewnfield": http://geology.com/meteorites/meteorite-hunting.shtml
- Here's an interesting article about how a team of Texas State University astronomers used forensic astronomy to solve an old mystery involving Walt Whitman: http://www.txstate.edu/news/news_releases/news_archive/2010/06/YearOfMeteors060110.html
Here's a brief rundown on the basic star types of stars in order from youngster to old fogey:
This stage of "stardom" lasts roughly 100,000 years and is near the beginning. Gas becomes a prostar once it collapses down into a molecular cloud.
T Tauri Star
This stage comes next and will last about 100 million years. During this stage, the star still doesn’t have enough energy to create its own nuclear fusion. It will be held together by gravity.
Main Sequence Star
Most of the stars in our galaxy are main sequence stars, including our very own sun. These stars convert hydrogen into helium at their cores.
Red Dwarf Star
These are the most common stars in the universe. They’re a type of main sequence star, but because they have such small mass, they’re much cooler. They burn a lot longer than regular main sequence stars; some astronomers estimate that there are red dwarfs that will burn for 10 trillion years!
- Proxima Centauri, the star closest to us – 4.2 light-years away – is a red dwarf star. Check out this StarDate radio episode about Proxima Centauri: http://stardate.org/radio/program/2009-04-16
Red Giant Star
Now nuclear fusion stops and the star no longer creates outward pressure so there's nothing counteracting the inward pressure pulling it in. But, for other reasons, a red giant star will still be up to 100 times bigger than it was in its main sequence stage.
White Dwarf Star
Once the star has completely run out of hydrogen and cannot do anymore fusion reactions, it becomes a white dwarf star. Now it collapses inward under its own gravity. It will cool down until it becomes the temperature of the universe. That will take hundreds of billions of years.
This is an exotic star with a core composed entirely of neutrons. The intense gravity of a neutron star crushes electrons and protons together to create the center’s neutrons. Very special circumstances must occur in order for a neutron star to be created.
These stars are the biggest in the universe and are ten times the size of our sun. Because of their impressive bulk, they will burn through their fuel in just a few million years (quickly by astronomy standards!).
Stargazing in State Parks
Calendar of stargazing events in Texas State Parks
And, while we've included some of our top picks here, you can see some other great places to see some great night skies at:.
Davis Mountains State Park:
When you camp at Davis Mountains State Park you're not only under those dark west-Texas skies, but you camp close to the world-famous McDonald Observatory, home to the amazing Hobby-Eberly telescope!
The Hobby-Eberly (HET) has the world’s largest telescope mirror. Because of the way HET is designed, only portions of the mirror can be used at one time. That's why even though the mirror is ranked as the largest in the world, the telescope itself gets ranked as number four.
and here: McDonald Observatory, "Hobby-Eberly Telescope:" http://www.as.utexas.edu/mcdonald/het/het.html
Big Bend Ranch State Park:
Stay and stargaze in west Texas, the darkest place in the continental U.S.
Purtis Creek State Park:
This east-Texas state park consistently hosts many stargazing activities.
Copper Breaks State Park:
North Texas near the Panhandle has dark night skies that make for extra special star staring!
Brazos Bend Park:
See alligators during the day and outer space through the telescopes of George Observatory at night!