WANT TO VIEW A GREAT SUMMER SPECTACLE? Take in Wyoming’s ultimate drive-in theater Travis Laurence You might notice dark regions ow is a wonderful time to stay within the band of light of the Milky Nup late, go outside, and see Way. These are called dark nebula some of the amazing summer stars and are clouds of interstellar dust. and constellations. Astronomers use the term “interstel- Something that might catch your lar dust” to describe tiny particles wonder is the bright band of light we of matter found throughout space. call the Milky Way. The farther you These dust clouds may be light-years can get from city lights, the more in size and contain material that obvious this pale, diffuse band be- some day may be formed into stars comes. You are looking at part of the and planets. They absorb light from galaxy in which we live. those millions of unseen stars behind Our galaxy is a massive collec- them. tion of 200 billion to 400 billion stars. In effect, you can get a sense of All of the stars you see in the night depth if you see a star within a dark sky are part of the Milky Way. About nebula. The star is in front of the 3,000 of these stars can be seen on a cloud, and behind the cloud is light clear night. That is a lot of stars! from the Milky Way. Stars within the But what we see with our eyes is constellation Cygnus (described be- only a tiny fraction of the stars within low) are a great example of this. our galaxy. Summer Travelers The Milky Way is also somewhat As summer comes so do three flat in that the thickness is small stars – Vega, Altair, and Deneb – that compared to the diameter. Our galaxy straddle the Milky Way and form is between 100,000 to 150,000 light- the Summer Triangle. These stars in years across and only a paltry 1,000 early summer are in the east after light-years thick. One light-year is sunset and, as summer progresses, about 6 trillion miles. You are looking will progress from east to west, so at this 1,000 light-year plane of the in mid-summer they will be close to galaxy. Most of the stars are too far straight overhead at sunset. away for our eyes to resolve. The Summer Triangle is not A pair of binoculars or a small an official constellation, as these telescope allows us to see so much stars all lay within their own distinct more in the Milky Way. constellations. SUMMER 2015 25 Vega is the brightest of the three which can translate to “Not-Mars” or and is one of the brightest stars in the “Rival of Mars.” sky. It is in the constellation Lyra, which There is a planet in this area is most easily imagined as a harp. slightly west of Scorpius, very pale yel- Vega is a white star, which means it is low in color and slightly dimmer than very hot, around 10,000 degrees at its Antares. This is Saturn, the farthest surface. Our yellow sun is around 6,000 planet we can see with our eyes. degrees at its surface. Vega is twice Scorpius as massive as the sun and about 40 Beautiful Rings Saturn will spend our summer times brighter. Vega is relatively close – just ahead of Scorpius’ claws. As the around 30 light-years from us. Dolphins, Scorpions year progresses, Saturn will slowly The second brightest star is To the east of the summer triangle move farther from Scorpius. The stars Altair, which is in the constellation is a small and faint constellation called in the night sky seemed to be fixed in Aquila the Eagle. Altair is even closer Delphinus the Dolphin. This constel- their relative positions – the constella- than Vega to us, lying at a distance lation is nice in that (to me at least) it tions seem to retain their shapes over of around 16 light-years. It is about actually looks like a dolphin. You can time. However, ancient astronomers twice as massive as our Sun. imagine her jumping out of the Milky noticed these objects such as Saturn Deneb, the faintest star in the Way and flipping her tail through space. that moved throughout the constella- Summer Triangle, is actually the larg- Follow the Milky Way south and you tions. They called these objects “wan- est and brightest of the three. Deneb can find two interesting constellations dering stars,” which in Greek is asteres is over 2,000 light-years away from low on the horizon. Scorpius starts in planetai, hence we call them planets. us, is 20 times more massive than our the Milky Way and extends toward the The constellation Sagittarius is sun, and over 200,000 times brighter! west. Scorpius is a scorpion that bested east of the scorpion. Sagittarius is a Deneb would extend out almost to the mighty Orion when they were both centaur with a bow and arrow, but Earth with Mercury and Venus inside on Earth. Every summer when Scorpius most people know this constellation if substituted for the sun. rises, Orion flees until the scorpion is no by its unofficial name, the Teapot. Deneb is in the constellation longer in the sky. This representation works great if you Cygnus the Swan. Cygnus is also An interesting star in Scorpius is imagine the Milky Way as steam com- known as the Northern Cross in Antares. This bright-red star rep- ing out of the spout. contrast to a constellation called the resents the heart of the scorpion You might notice the Milky Way Southern Cross visible in the southern and is also very similar in color and looks rather spectacular in this direc- hemisphere. brightness to Mars. Scorpius is a tion toward the center of our galaxy. zodiac constella- It is wide and bright, full of milky tion in that the path patches and dark clouds. of the sun passes through this constel- Big, Very Big Black Hole lation. Because our The galactic center lies within a sun and planets lie dark nebula just above the spout of within a fairly flat the Teapot. The center of our gal- plane, the planets axy is estimated about 24,000 to also pass though 28,000 light-years away from us. this constellation. Astronomers believe there is a super- Mars (aka Ares) massive black hole at the center. can sometimes be Black holes have enough mass found right next that light is not moving fast enough to Antares, hence to escape. Think about throwing a the name Ant Ares, There are no Unidentified Space Objects in Travis Laurance’s vocabulary. He is the laboratory coordinator in the Department of Physics and Astronomy at the University of Wyoming. He can be reached at (307) 766-4371 or at [email protected]. 26 BARNYARDS & BACKYARDS ball into the air. It comes back to the DON’T MOVE FIREWOOD! surface every time because we cannot throw it fast enough to escape Earth’s gravity. A black hole is so massive that Firewood can carry insects and diseases that kill trees. Remember to the fastest moving thing we know of, always get firewood as close to your destination as possible. Burn light, falls back to the surface. firewood where you buy or gather it. Trees The black hole at the center of our galaxy is estimated to be over 40 mil- in towns and forests are threatened by lion times the mass of our sun. This native and exotic insects and diseases much mass affects objects around it; that can hitch a ride in a load of firewood. that’s how we know the black hole Let’s keep forests healthy so we can exists. Astronomers see stars orbiting continue to enjoy camping, hiking, around nothing, but that nothing must be a massive object. hunting, and fishing. Brought to The summer night sky is full of won- you by the Wyoming State Forestry ders and beautiful objects. Whether you Division in cooperation simply enjoy the splendor of the Milky with the US Forest Way overhead or find wonder in real- Service. izing you might be looking toward the center of our galaxy 26,000 light-years away, the summer night sky in Wyoming is worth staying up for. Missed an issue? Back issues of Barnyards & Backyards are now available! See the website www.barnyardsandbackyards.com or call (307) 766-2115 for more information. 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