Comets - Visitors From Beyond. The one thing we love the most in the world of astronomy is a good mystery. And if there was ever a mysterious and yet very powerful force of nature that we witness in the night skies, it is the coming of the mighty comet. The arrival of a comet within view of Earth is an event of international importance.
Witness the huge media attention that the Haley or Hale-Bopp have had when they have come within view The sight of these amazing space objects is simultaneously frightening and awe inspiring. Above all, it is during these comet viewings that the astronomer comes out in all of us. But what is a comet? Where did it come from?
And how does it get that magnificent tail? We should never confuse comets with asteroids. Asteroids are small space rocks that come from an asteroid belt between Mars and Jupiter. While still quite stunning to see, they pale in comparison to the arrival of a comet.
Asteroids also have received considerable study by the scientific community. Not as much is known about comets. As a rule, comets are considerably larger than asteroids. The composition of a comet is a mixture of nebulous, gasses, ice, dust and space debris.
One scientist called the composition of a comet as similar to a “dirty snowball” because the composition is so diverse and changeable. The center or nucleus of a comet is usually quiet solid but the “snowball” materials often create a “cloud” around that nucleus that can become quite large and that extends at great lengths behind the comet as it moves through space. That trailing plume is what makes up the comet’s magnificent tail that makes it so exciting to watch when a comet comes within view of Earth. The origins of comets is similarly mysterious.
There are a number of theories about where they come from but it is clear that they originate from outside our solar system, somewhere in deep space. Some have speculated they are fragments left over from the organization of planets that get loose from whatever gravitational pull and are sent flying across space to eventually get caught up in the gravity of our sun bringing them into our solar system. Another theory is that they come from a gaseous cloud called the Oort cloud which is cooling out there after the organization of the sun. As this space debris cools, it gets organized into one body which then gathers sufficient mass to be attracted into the gravity of our solar system turning into a fast moving comet plummeting toward our sun. However, because of the strong gravitational orbits of the many planets in our solar system, the comet does not always immediately collide with the sun and often takes on an orbit of its own. The life expectancy of comets varies widely. Scientists refer to a comet that is expected to burn out or impact the sun within two hundred years as a short period comet whereas a long period comet has a life expectancy of over two hundred years. That may seem long to us as earth dwellers but in terms of stars and planets, this is a very short life as a space object indeed. Scientists across the globe have put together some pretty impressive probes to learn more about comets to aid our understanding of these visitors from beyond. In 1985, for example, the United States put a probe into the path of the comet Giacobini-Zinner which passed through the comets tail gathering tremendous scientific knowledge about comets. Then in 1986, an international collation of scientists were able to launch a probe that was able to fly close to Haley’s comet as it passed near Earth and continue the research. While science fiction writers and tabloid newspapers like to alarm us with the possibility of a comet impacting the earth, scientists who understand the orbits of comets and what changes their paths tell us this is unlikely. That is good because some comets reach sizes that are as big as a planet so that impact would be devastating. For now, we can enjoy the fun of seeing comets make their rare visits to our night sky and marvel at the spectacular shows that these visitors from beyond put on when they are visible in the cosmos. PPPPP 728
Dude, You’re Getting a Telescope! You might remember the Dell computer commercials in which a youth reports this exciting news to his friends that they are about to get their new computer by telling them, “Dude, you’re getting a Dell!” It was a cute series but it reflects the excitement young people get about anything new, particularly if it’s a new machine. So when its time to finally get your children that very first telescope, you want to make sure it’s just the right thing. There are a number of reasons you should put some serious thought into just what this beginner telescope should look like.
Perhaps this will be your children’s first experience with a real telescope. They may have a healthy and thriving love of astronomy from your family trips to the country to watch a meteor shower or just to gaze at the stars. And you may have piqued their interest showing them how to enhance the experience with binoculars or even letting them play with your telescope. But this is a big moment. You want them to “bond” with this first telescope the way you did and catch the excitement of using the power of a telescope to do things with their love of astronomy that they could never do before.
The reasons for taking care with your choice are many including… * A telescope is a big step into the lifelong hobby of astronomy. If they get the wrong thing, frustration could make them lose interest both in the machine and in the field of study. * Kids have a short attention span.
You want this beginner telescope to take them from where they are to the next level while giving them those gratifying moments discovering new things in the stars every time they use it. * It has to be a hardy piece of equipment. Kids don’t always know how to treat delicate equipment. So the starter telescope should have some good “training wheels” on it. * It has to be their teacher even when they don’t know they are in school. A good beginner telescope, accompanied by some stimulating documentation that is written just for kids will stimulate their excitement and use it to teach them to work hard to reach new heights in their quest for knowledge about the stars. A lot about how you go about getting this first telescope will depend on your own expertise in astronomy. If it is your passion and you have developed a pretty sophisticated knowledge about telescopes over the years, you not only are well equipped to make this choice but you will be there to guide them as they begin to use it. But if you are just encouraging them in a wonderful hobby that you yourself have not been involved with in depth, first of all, congratulations. You are giving them a wonderful gift of not only knowledge but the love of astronomy and the natural wonder of nature. But you also need some help. So here are some quick guidelines. * Find the astronomy geeks. They are easy to find in hobby shops, astronomy clubs and societies at the local college. They will help you enthusiastically. * Look at the telescope you are considering through their eyes. It should not be too complex. Don’t get something that will intimidate them. * Don’t buy a toy. Your kids will know the difference. * Make sure it can grow and be expanded as their knowledge expands. If you put some wise consideration into just the right starter telescope, your kids will be as excited they have ever been for a gift. Don’t be surprised if you hear one of them squeal, “Dude, you got a telescope!” PPPPP 624
How to Look Up The beauty of astronomy is that anybody can do it. From the tiniest baby to the most advanced astrophysicist, there is something for anyone who wants to enjoy astronomy. In fact, it is a science that is so accessible that virtually anybody can do it virtually anywhere they are. All they have to know how to do is to look up. It really is amazing when you think about it that just by looking up on any given night, you could see virtually hundreds of thousands of stars, star systems, planets, moons, asteroids, comets and maybe a even an occasional space shuttle might wander by. It is even more breathtaking when you realize that the sky you are looking up at is for all intents and purposes the exact same sky that our ancestors hundreds and thousands of years ago enjoyed when they just looked up. There is something timeless about the cosmos. The fact that the planets and the moon and the stars beyond them have been there for ages does something to our sense of our place in the universe. In fact, many of the stars we “see” with our naked eye are actually light that came from that star hundreds of thousands of years ago. That light is just now reaching the earth. So in a very real way, looking up is like time travel. Everybody knows how to look up. Children first discover the amazing light show on display for free every clear night by just looking up. You can probably remember that very first time you noticed that explosion of stars above you when you were a child. Now it is time to foster that same love of astronomy in your own children. You have to teach them how to look up. While anyone can look up and fall in love with the stars at any time, the fun of astronomy is learning how to become more and more skilled and equipped in star gazing that you see and understand more and more each time you look up. Here are some steps you can take to make the moments you can devote to your hobby of astronomy much more enjoyable. * Get out of town. The furtherest you can get from the lights of the city, the more you will see in the night sky. * Know what you are looking at. It is great fun to start learning the constellations, how to navigate the night sky and find the planets and the famous stars. There are web sites and books galore to guide you. * Get some history. Learning the background to the great discoveries in astronomy will make your moments star gazing more meaningful. It is one of the oldest sciences on earth so find out the greats of history who have looked at these stars before you. * Get a geek. Astronomy clubs are lively places full of knowledgeable amateurs who love to share their knowledge with you. For the price of a coke and snacks, they will go star gazing with you and overwhelm you with trivia and great knowledge. * Know when to look. Not only knowing the weather will make sure your star gazing is rewarding but if you learn when the big meteor showers and other big astronomy events will happen will make the excitement of astronomy come alive for you. And when all is said and done, get equipped. Your quest for newer and better telescopes will be a lifelong one. Let yourself get addicted to astronomy and the experience will enrich every aspect of life. It will be an addiction you never want to break. PPPPP 615
Look – Up in the Sky! When television was young, there was a hugely popular show based on the still popular fictional character of Superman. The opening of that show had a familiar phrase that went, “Look. Up in the sky. It’s a bird. It’s a plane. It’s Superman!” How beloved Superman has become in our culture and the worldwide fascination with extraterrestrials and all things cosmic only emphasizes that there is a deep curiosity in all humans about nature and astronomy, even if many people would not know to call it astronomy. Astronomy is one of the oldest sciences of all time. When archeologists unearth ancient civilizations, even as far back as the cavemen, they invariably find art that shows mans unquenchable fascination with the stars. To this day, you can easily get an animated discussion at any gathering on the topic of “Is there intelligent life on other planets?” Many have tried to explain mankind’s seeming obsession with outer space as a result of an ancient memory or as part of mankind’s eternal nature. Whatever the cause, people of every age and every nation share this one deep interest, to know more about the universe that our tiny planet is just a part of. It’s rather strange because the actual conduct of a serious student of astronomy is really not the stuff of high adventure. You will never see a “Raiders of the Lost Arc” or “Jurassic Park” movie made about an astronomer. Excitement for lovers of this science is to stay up all night watching the cosmos through a powerful telescope. But that fact does not seem to discourage the tens of thousands to get into astronomy each year and the huge interest worldwide with the stars, the planets and the universe. There may be no other universal human fascination that does so much to make national boundaries and even international animosity seem to evaporate. Other than the Olympic movement, international cooperation to achieve great strides for human kind in space seems to go forward without interruption even when the nations cooperating in those projects are virtually at war back on the surface of the earth. It is a strange thing to watch as Russian, American and other astronauts work together like brothers on space missions even as their home nations are busily pointing missiles at each other back at home. It almost makes you think that we should put more energy and money into the space program, not less because it seems to be a bond that heals tension rather than creates it. Why is astronomy so exciting even though we have no dinosaurs, moving animals or any real danger to most who are obsessed with the discipline? It may go back to a basic curiosity that all human beings have about their natural habitat and this big mysterious thing out there called space. Maybe it goes back to that old saying at the beginning of Star Trek that space is “the final frontier”. But we all share that ongoing sense of excitement each time we take out our telescopes and gaze directly at the cosmos above us. We feel we are looking at the very dawn of time. And in light of the issues with the speed of light which means that many of the twinkling stars out there are really light from those stars that started their journey to us thousands of years ago, we are in actually looking directly at the past every time we direct our eyes skyward. But we don’t have to worry about ever conquering the final frontier and finding our curiosity satisfied. There will always be more to learn and discover in the world of astronomy. And it is likely that mankind’s curiosity about astronomy is just as limitless as well. PPPPP 633
Moon Fever Of all of the celestial bodies that capture our attention and fascination as astronomers, none has a greater influence on life on planet Earth than it’s own satellite, the moon. When you think about it, we regard the moon with such powerful significance that unlike the moons of other planets which we give names, we only refer to our one and only orbiting orb as THE moon. It is not a moon. To us, it is the one and only moon. The moon works its way into our way of thinking, our feelings about romance, our poetry and literature and even how we feel about our day in day out lives in many cases. It is not only primitive societies that ascribe mood swings, changes in social conduct and changes in weather to the moon. Even today, a full moon can have a powerful effect on these forces which we acknowledge even if we cannot explain them scientifically. The most obvious physical phenomenon that is directly affected by the gravity of the moon are the tides of the ocean. The tides are an integral part of how maritime life is regulated and the comings and goings of the fishing world in coastal communities. But not very many people know that at certain times of the year when the orbits of the earth bring the sun and moon into right alignment, there can even be tidal effect on inland bodies of water and even on the solid earth. Eons ago, when the moon’s orbit was closer to the Earth, it was the effect of the moon that caused massive changes in the topography of the land and on continental drift as well. This reflects the powerful effect the moon has had on both human history and on global geographical history as well. You may sometimes wonder where the moon came from. Was it a planet that traveled too close to Earth and was captured in our orbit? Actually, the prevailing theory of modern science is that the moon was the result of a large scale collision with the still developing Earth early in its development which caused this large “chuck” to spin off into an orbiting body. This explains the similarity in composition as has been confirmed by many of the moon exploratory space missions that were conducted by NASA. But this background also highlights another important influence the moon has had on Earth’s development that is seldom recognized and that is the stabilization of Earth’s orbital pattern. Most know that Earth is not round but more of an egg shaped orb. To be blunt, the Earth would wobble. Without the moon’s stabilizing influence, this shape would shift dramatically so the tilt of the axis, that is the polar caps would shift dramatically with each seasonal rotation producing climacteric, changes much more violent and drastic than we are used to. It is possible that life as we know it could not have developed here had the moon not been there to “keep the Earth in line” and continue to stabilize the orbital position of the Earth so our climate could remain stable and mild. A third significant influence of the moon comes from that origin as coming from a collision which “ripped” the body of the moon from the developing core of the Earth. Because of this disruption in how the core of our planet developed, the metals that are usually intact in the core of the planet are actually scattered up and down the geography of the earth in diverse ways. Usually the metals of the planet are all concentrated deep in the core. But because of the collision which took the moon out to orbit, metals that have been crucial to the development of our industrial and technological cultures are readily available and easy for use to mine. This again, is something we can thank the presence of that lovely moon in the sky for. PPPPP 660
Moon Gazing For many of us, our very first experience of learning about the celestial bodies begins when we saw our first full moon in the sky. It is truly a magnificent view even to the naked eye. If the night is clear, you can see amazing detail of the lunar surface just star gazing on in your back yard. Naturally, as you grow in your love of astronomy, you will find many celestial bodies fascinating. But the moon may always be our first love because is the one far away space object that has the unique distinction of flying close to the earth and upon which man has walked. Your study of the moon, like anything else, can go from the simple to the very complex. To gaze at the moon with the naked eye, making yourself familiar with the lunar map will help you pick out the seas, craters and other geographic phenomenon that others have already mapped to make your study more enjoyable. Moon maps can be had from any astronomy shop or online and they are well worth the investment. The best time to view the moon, obviously, is at night when there are few clouds and the weather is accommodating for a long and lasting study. The first quarter yields the greatest detail of study. And don’t be fooled but the blotting out of part of the moon when it is not in full moon stage. The phenomenon known as “earthshine” gives you the ability to see the darkened part of the moon with some detail as well, even if the moon is only at quarter or half display. To kick it up a notch, a good pair of binoculars can do wonders for the detail you will see on the lunar surface. For best results, get a good wide field in the binocular settings so you can take in the lunar landscape in all its beauty. And because it is almost impossible to hold the binoculars still for the length of time you will want to gaze at this magnificent body in space, you may want to add to your equipment arsenal a good tripod that you can affix the binoculars to so you can study the moon in comfort and with a stable viewing platform. Of course, to take your moon worship to the ultimate, stepping your equipment up to a good starter telescope will give you the most stunning detail of the lunar surface. With each of these upgrades your knowledge and the depth and scope of what you will be able to see will improve geometrically. For many amateur astronomers, we sometimes cannot get enough of what we can see on this our closest space object. To take it to a natural next level, you may want to take advantage of partnerships with other astronomers or by visiting one of the truly great telescopes that have been set up by professionals who have invested in better techniques for eliminating atmospheric interference to see the moon even better. The internet can give you access to the Hubble and many of the huge telescopes that are pointed at the moon all the time. Further, many astronomy clubs are working on ways to combine multiple telescopes, carefully synchronized with computers for the best view of the lunar landscape. Becoming part of the society of devoted amateur astronomers will give you access to these organized efforts to reach new levels in our ability to study the Earth’s moon. And it will give you peers and friends who share your passion for astronomy and who can share their experience and areas of expertise as you seek to find where you might look next in the huge night sky, at the moon and beyond it in your quest for knowledge about the seemingly endless universe above us. PPPPP 642
Our Neighbors in Space We have a special feeling toward the other planets that circle our sun. Maybe it’s all the science fiction stories about visiting the moon, Mars and other planets. But we love to think about those planets that make up what we call “the solar system.” that do what our planet does but do it very differently indeed. The planets of our solar system have taken on personalities and mythical appeal in our literature and arts. It is easy to find artists who render their vision of the planets that make up our society of planets near our sun. The names of the planets, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune are all from our cultural past being gods from Greek and Roman mythology. But the solar system is not just made up of these planets. The solar system is a very busy place indeed. In 2006, there was quite a bit of controversy as scholars and astronomers agreed to downgrade Pluto and remove its status as a planet. So you have to wonder, what is it that makes something a planet and what happened to Pluto? It didn’t just go away so it must still be out there. A planet, by scientific definition is any object in orbit around a sun, that has formed into some kind of round object is a planet as long as it has cleared away any other orbiting items around it. By cleared away, that doesn’t mean it has destroyed all space debris etc. For example, our planet has not “cleared away” the moon but it has captured it into its own orbit so we classify as a planet. That’s a relief huh? There are many objects floating around in our solar system other than the planets we know of. It’s an interesting piece of trivia that in addition to the planets there are 165 moons orbiting around those nine planets. Some of those moons are so advanced that some scientists have suspected that they might have supported life at some point. In addition to the regular planets and moons, there are dwarf planets, asteroid belts and routine visits by comets that create a lot of traffic in our cosmic corner of the universe. The two known dwarf planets that exist on the outer rim of our solar system are Eries and Ceres. So when Pluto’s status was changed to be removed from the list of planets, it simply joined those two bodies as dwarf planets but still a solid citizen of the community of celestial bodies around our sun. In addition to these larger bodies, there is an asteroid belt that exists between Mars and Jupiter that most of the asteroids that we see in our night sky come from. There is another belt of large objects further out called the Kuiper belt as well as a “bubble” in space called a heliopause and there is a suspected additional belt outside the known solar system called the Oort belt that we think is the origin of a lot of large asteroids and comets that frequent our solar system and come to orbit our sun. As fascinating as these many celestial bodies who are our neighbors in space is the origin of our solar system. We have to break it down to simple terms to understand the terms but we know that the early history of the solar system and the universe was one of great bodies of gas and clouds of matter eventually cooling and heating, exploding and spinning off stars and other massive space giants that became more stars, galaxies and solar systems. It was from this erratic activity that our sun separated from the gasses and carried with it the material that became our solar system. The gravity of the sun captured sufficient matter that it began to go through the process of forming, cooling, exploding and separating. This is what happened as the planets all went through he same process eventually establishing stable orbits and small objects falling into orbit around them. When you think of how powerful and out of control this process is, it’s amazing to step back and see the beauty of the organization of our solar system today. The more detail you learn about the history of our solar system, the more you will enjoy your explorations of the planets with your telescope. That that discovery is part of the fun of astronomy. PPPPP 744
Pictures in the Sky One of the earliest activities we engaged in when we first got into astronomy is the same one we like to show our children just as soon as their excitement about the night sky begins to surface. That is the fun of finding constellations. But finding constellations and using them to navigate the sky is a discipline that goes back virtually to the dawn of man. In fact, we have cave pictures to show that the more primitive of human societies could “see pictures” in the sky and ascribe to them significance. Constellations also have been important in culture and navigation long before we had sophisticated systems of navigation. Early explorers, particularly by sea, relied exclusively on the night sky to help them find their way to their destination. In fact, when “Columbus sailed the ocean blue in 1492” and “discovered” America, he could not have done it without astronomy and the help of navigation of the cosmos, much of which is made possible because of the important constellations. When learning to find the great constellations in the sky, we use the “find one, you found them all” system. That is because the easiest constellation to find will guide us to the rest of them. That constellation is The Big Dipper. Look to the northern sky on a clear night and widen your field of vision from just focusing on one star and it will pretty much jump out at you. In will look like a big kitchen pot or ladle, right side up in the fall, upside down in the spring. When you have the big dipper under control, you can pretty easily find the North Star. This is the star that those ancient sailors depended on the most to find their way to land. Start with the far edge of the bowl of the Big Dipper, the side that is opposite the handle. There are two stars that make up that side of the bowl. So start at the bottom of the pot and mentally draw a line to the top star of the bowl. These two stars are “pointing” to the North Star. Just keep following that line, curving a bit with the sky and the bright star that you come to is the North Star. You can impress your friends or family if you know the scientific name for this star is Polaris. The North Star can then take you to The Little Dipper. The key here is that Polaris is the tip of the handle of The Little Dipper and the bowl hangs down from the handle like it was hanging up in the kitchen. Be patient with this one as the stars that make up The Little Dipper are dimmer than The Big Dipper. But it pretty cool once you find it. These are the obvious starting places but from The Little Dipper you can find the constellation known as “The Swan” or Cygnus. Just use the same system you used to find The North Star but continue drawing that line that started in those pointer stars in the bowl of The Big Dipper. Go about half as far as you went to find Polaris and you are there. You will see a trapezoid of stars about as big as The Big Dipper. This trapezoid forms the tail of The Swan. That line that we are drawing from the pointer stars is our roadmap to another well known constellation which is Cassiopeia. If you use that line and imagine you are directly under the two pointer stars, you will se a big “W” just off to the left of the line. This is the constellation Cassiopeia, the wife of the king of Egypt, Cepheus, in Greek mythology. There are so many more wonderful constellations to find and a good star map can continue your quest. Like Cassiopeia, all of the constellations have wonderful stories and myths related to Greek culture. It is just as fun to find the star clusters themselves as it is to enjoy the rich culture related to that constellation. For all of the signs of the zodiac, for example, there is a related constellation in the sky. So whether you are serious about astrology or not, its fun to find the constellation that relates to your “sign” (or that of your children) and be able to see how the ancients related to these pictures in the sky. PPPPP 743
Radio Astronomy For most of us, the idea of astronomy is something we directly connect to “stargazing”, telescopes and seeing magnificent displays in the heavens. And to be sure, that is the exciting area of astronomy that accounts for it’s huge popularity. So to the uninitiated, the idea of “radio astronomy” seems strange. There are two reasons for that. First is that humans are far more visual than audio oriented. And the second is that radio astronomy doesn’t really involve “listening” to the cosmos except to the extent that scientists who use this sophisticated form of “stargazing” do not rely on visual study to conduct their work. To appreciate what is really exciting about radio astronomy, first we have to shift how we view astronomy. That is because to professional astronomers, studying the universe is more about frequencies than it is about visual documentation of phenomenon. This takes us back to Physics 101. Light, obviously, is the physical phenomenon that empowers our ability to use our visual confirmation system, e. g. our eyes to appreciate something, in this case the stars. So when we look up at the heavens, we can see the light emitting from a star or reflecting from a planet or moon. In many cases, if we see a far away star, we are actually seeing it hundreds or thousands of years ago because that is how long it takes for that light to cross the universe and be visible in our sky. That alone is a pretty mind blowing idea. Now light itself is a pretty strange substance. But to our astronomy scientists, light is just another energy that exists in a certain frequency. Now, we tend to think of frequencies when we talk about sound waves. In scientific terms light, energy and sound are just a few forms of the same thing, frequencies of energy that are emulating from a source. Now we get to why radio astronomy is so necessary. The range of frequency that light occupies in the big spectrum of frequencies is really pretty small. To put that more bluntly, we can only “see” a tiny part of the universe that is actually there. Now when you look up in the night sky and it is so overwhelming, when you then that we are seeing just a tiny amount of what is actually going on up there, again, our minds can get pretty overwhelmed. Radio astronomy uses sophisticated sensor equipment to study ALL of the frequencies of energy coming to us from the cosmos. In that way, these scientists can “see” everything that is going on out there and so get a precise idea of how the stars look, behave now and will behave in the future. For some of us who have heard about radio astronomy, we think of it in terms of “listening” for signs of life in the universe. And yes, SETI, or “the Search for Extra Terrestrial Intelligence” is a part of radio astronomy, albeit a tiny part. But of much greater importance is how radio astronomy has empowered serious astronomers (that is those who get paid to do it) to study stars many light years away, to study black holes which we could never see with our telescopes and to gather research and data about the whole of the universe that otherwise would be impossible to know and understand. This is important work that is constantly ongoing in the world of astronomy. It is worth keeping up with and learning more about as we have barely scratched the surface in our brief discussion today. But understanding how important radio astronomy is will only deepen and make more meaningful your love and grasp of this big field of knowledge known as astronomy. PPPPP 625
Shooting Stars If you are a serious astronomy fanatic like a lot of us are, you can probably remember that one event in childhood that started you along this exciting hobby. It might have been that first time you looked through a telescope. But for many of us, it was that first time we saw a rain of fire from the sky that we eventually came to know as a meteoroid shower. At the time when you see the first one, it’s easy to remember the movie “war of the worlds” or some other fantastic image of aliens entering our atmosphere in droves to take over the planet. But with some guidance and explanation of what was going on, we eventually learned that these showers were not at all threatening or any kind of invasion. For the most part meteoroid showers are harmless, part of nature and very fun to watch. So what are these strange lights in the sky? Are they aliens invading from Mars? Are the comets coming to start the next ice age? Or perhaps asteroids burning up as they enter the earths atmosphere. The answer to the above questions is no to the first and “yes and no” to the other two. A meteoroid is actually a small piece of space rubble, usually dust or small rocks that come from either a comet or the break up of an asteroid in space and that eventually plummets toward the earth. We say “toward the earth” because the lights you see are the friction of the atmosphere burning up those small space tidbits and creating a spectacular show for all of us as they do so. A particularly exciting moment to witness is when a meteoroid breaks up or explodes on entry. A meteoroid that explodes is called bolides. There are some interesting details about the life of a meteoroid that make the viewing of shooting stars even more fun. To be seen, a meteoroid only needs to weigh as little as a millionth of a gram. But the thing that makes them so spectacular to see is the tremendous speeds they reach as they enter the atmosphere. Before burning up, a meteoroid will reach between 11 and 74 kilometers per second which is 100 times faster than a speeding bullet. We tend to think of t seeing a shooting star as a freak event and we associate it with superstition (hence, wish on a lucky star). But there are actually thousands of them every year so it really isn’t that rare to see one. In fact, scientists tell us that over 200,000 tons of space matter enters the atmosphere each year and burns up on entry. Comets are a big source of meteoroids because of the nature of those long tails. A large amount of dust, ice and other space debris gets caught up in a comet’s tail as it moves toward the sun. Then as the comet moves away from the sun in its orbit, tons of this matter is thrown off into space to disperse. As the Earth moves in its routine orbit around the sun, it often crosses through clouds of this discarded matter which becomes one of those “meteor showers” that are so popular for viewing. These showers of shooting stars are pretty easy for astronomers to predict so you can get into position to see the excitement at just the right time of night and be looking at the right area of the night sky. Usually the astronomy magazine or site will give you a general time and location to be ready to look when the meteoroids start to fall. Now keep in mind, this is a phenomenon of nature, so it may not observe the time table exactly. Also note that there is a notation system for where the meteoroid shower will occur based on what constellation is its backdrop. The section of the sky to focus on for the show is called the “radiant” because that is where the entering meteoroids begin to glow or radiate. The radiant is named for the constellation it is nearest too. So if the meteor shower is going to occur in the constellation of Leo, then its radiant will be called Leonid. This will help you decipher the listing of asteroid showers in the publications. PPPPP 723
Space, The Final Frontier While it was just a TV show, that little speech at the beginning of the original Star Trek show really did do a good job of capturing our feelings about space. It is those feelings that drive our love of astronomy and our desire to learn more and more about it. The thing that is most exciting about studying the universe is also the most frustrating and that is that no matter how expert we get, we are always just getting started. But if it’s any consolation, some of the most advanced minds in science and from history always felt that way about space. Even the greats such as Copernicus and Einstein looked up into space and felt like they were just a spec in the presence of such infinity. Of course space is not infinite. It has to be finite which means somehow there must be an end to it. But if there is, nobody on this tiny planet has figured out where it is. The only thing that has brought us to “the end of the universe” is our limited ability to see any deeper into space. But conquering the final frontier of space means more than just seeing more stars and planets and building the biggest telescope we can. There are some mind blowing concepts about how space works that we have ahead of us to conquer. The big bang and the expanding universe alone was enough to set your mind to spinning. But then we have the coming of Einstein and the theory of relativity to set the entire idea on its ear. All of a sudden space is not just three dimensions but the dimension of time becomes exportable and the twisting and maybe even travel through time seems almost possible. The frontier of space is as much a journey of the mind as it is of distance. When Steven Hawking showed us the mysteries of black holes, all of a sudden, time and space could collapse and be twisted and changed in those intergalactic pressure cookers. If not for the wonders of radio astronomy, these ideas would remain just ideas but slowly science is catching up with theory. But the brilliance of mathematicians and genius minds like Hawking and Einstein continue to stretch our concepts of space. Now we have the string theory that could revolutionize everything we know about space, time and how the universe relates to itself. We can’t just say, no, we have discovered enough. It’s the final frontier. The Starship Enterprise would not stop exploring so neither can we. Because there is a hurdle still ahead that has a name but no real answer to it yet. It’s called the Unified Field Theory and those that know tell us that when the Einsteins and Hawkings of our day crack that theory, every other theory will fall into place. These exciting concepts seem some tools to put the enormity of space in context. That may also be the value of science fiction. Not only are science fiction writers often the visionaries of what comes to be in the future but they give us the idea that space is knowable, that despite how big it is and how small we are, we can conquer this frontier like we have conquered others before us. For mankind, that is often enough. If we can get the vision that we can conquer something, even if it is something so massive, so impossibly huge, it seems that we are capable of anything. And the love of astronomy, maybe unlike any other force on earth, has brought together mankind toward that common goal of conquering the universe. The quest to establish an international space station and to cooperate on spreading our reach off of this planet seems to find commonality between nations that otherwise cannot get along on the surface of the earth. That alone may be a reason that we must continue to support astronomy locally and the space program nationally. It is something that seems to bring peace rather than war and make us a better people. But more than that it is as though this is what we were created to do. To reach out to the stars may be our destiny. If so then our love of astronomy is more than a hobby, it’s a calling. PPPPP 729
Telescopes 101 Buying the right telescope to take your love of astronomy to the next level is a big next step in the development of your passion for the stars. In many ways, it is a big step from someone who is just fooling around with astronomy to a serious student of the science. But you and I both know that there is still another big step after buying a telescope before you really know how to use it. So it is critically important that you get just the right telescope for where you are and what your star gazing preferences are. To start with, let’s discuss the three major kinds of telescopes and then lay down some “Telescope 101” concepts to increase your chances that you will buy the right thing. The three primary types of telescopes that the amateur astronomer might buy are the Refractor, the Reflector and the Schmidt Cassegrain telescope. The first two are named for the kind of lens that is used. It is pretty easy to see that the lens is the heart of the telescope so the kind that you will use will determine the success of your use of that telescope. The refractor lens is the simplest because it uses a convex lens to focus the light on the eyepiece. So the lens bends outwards for this purpose. The refractor telescope’s strength is in viewing planets. The reflector’s strength is in seeing more distant objects and the lens is concave or bends in. It uses mirrors to focus the image that you eventually see. The final type, the Schmidt Cassegrain telescope is the most complex and accomplishes the goals of both but it uses an involved system of mirrors to capture the image you want to see. So to select just the right kind of telescope, your objectives in using the telescope are important. To really understand the strengths and weaknesses not only of the lenses and telescope design but also in how the telescope performs in various star gazing situations, it is best to do some homework up front and get exposure to the different kinds. So before you make your first purchase… * Above all, establish a relationship with a reputable telescope shop that employs people who know their stuff. If you buy your telescope at a Wal-Mart or department store, the odds you will get the right thing are remote. * Pick the brains of the experts. If you are not already active in an astronomy society or club, the sales people at the telescope store will be able to guide you to the active societies in your area. Once you have connections with people who have bought telescopes, you can get advice about what works and what to avoid that is more valid than anything you will get from a web article or a salesperson at Wal-Mart. * Try before you buy. This is another advantage of going on some field trips with the astronomy club. You can set aside some quality hours with people who know telescopes and have their rigs set up to examine their equipment, learn the key technical aspects, and try them out before you sink money in your own set up. There are other considerations to factor into your final purchase decision. How mobile must your telescope be? The tripod or other accessory decisions will change significantly with a telescope that will live on your deck versus one that you plan to take to many remote locations. Along those lines, how difficult is the set up and break down? How complex is the telescope and will you have trouble with maintenance? Network to get the answers to these and other questions. If you do your homework like this, you will find just the right telescope for this next big step in the evolution of your passion for astronomy. PPPPP 647
The Amazing Hubble In the history of modern astronomy, there is probably no one greater leap forward than the building and launch of the space telescope known as the Hubble. While NASA has had many ups and downs, the launch and continued operation of the Hubble space telescope probably ranks next to the moon landings and the development of the Space Shuttle as one of the greatest space exploration accomplishments of the last hundred years. An amazing piece of astronomy trivia that few people know is that in truth, only about ten percent of the universe is visible using conventional methods of observation. For that reason, the Hubble really was a huge leap forward. That is for the very simple reason that the Hubble can operate outside of the atmosphere of Earth. Trying to make significant space exploration via telescopes from the terrestrial surface of planet Earth is very difficult. That very thing that keeps us alive, our own Earth’s atmosphere presents a serious distraction from being able to see deeper and further into space. The Hubble space telescope was named after the great scientist and visionary Edward Hubble who discovered that the universe was expanding which was explained by what is now known in science as Hubble’s Law. To truly get a feel for the amazing accomplishment that was achieved with the launch of the Hubble telescope, spend some time on Nasa’s web site dedicated to the project at hubble. nasa. gov. There are also a number of sites where you can enjoy some stunning pictures from the Hubble including heritage. stsci. edu/ and stsci. edu/ftp/science/hdf/hdf. html. It’s hard to believe how long the Hubble has been orbiting earth and sending back amazing video and pictures of what it is discovering in space. But the Hubble was actually initially launched on April 25th 1990. It was the culmination of literally decades of research and construction which began in 1977. Expectations were high as the orbiting telescope was put in place and actually began to function as it was designed to do. All was not always perfect with the telescope and the early pictures were disappointing. After some study NASA discovered that the reason for the early failures was the curvatures of one of the main lenses of the orbiting telescope. We probably could never have kept this intricate piece of equipment operational as well as we have had we not had the Space Shuttle program to give us a tool to implement repairs and improvements to the Hubble. In 1993 a new lens was installed on the Hubble which corrected the problem of picture resolution that was noted in the early operation of the telescope. Two other repair and upgrade mission have been made to the Hubble since it launched, both of them in 1997 to upgrade older equipment and to retrofit the telescope to extend its useful life through 2010. It’s pretty amazing to think that this scientific and mechanical marvel has been operating now for ten years without maintenance. We can be assured that plans are in the works for NASA to upgrade or replace parts on the Hubble to extend its useful life even further as that 2010 time frame draws closer. It is hard to imagine the science of astronomy or the natural quest for greater knowledge of our universe without the Hubble. While many times those who would not fund space exploration have tried to cut funding for the Hubble, the operation of this telescope is just too important to astronomers and to the scientific well being of mankind and our planet not to continue to use the Hubble, or its next natural successor. We will always need to have a set of eyes in the sky to watch the universe and discover more of its mysteries. PPPPP 629
The Basics of Buying a Telescope There is a moment in the life of any aspiring astronomer that it is time to buy that first telescope. It’s exciting to think about setting up your own viewing station whether that is on the deck of your home or having a powerful but mobile telescope set up to take to the remove countryside to really get a good shot at some breath taking star gazing. The last thing we would want to do is to take away any of the “fun” of your hobby of astronomy because the joy of what we do as star gazers is a big part of the appeal. But unlike many other hobbies, ours is a passion of science, of learning and of discovery. And don’t kid yourself, even a hobbyist with a limited telescopic set up can see some amazing things in the stars. So let’s be sure you invest in a solid piece of equipment that you can continue to grow with as your knowledge and ability as an astronomer grows. But how do we do that? Meet the Geeks. Now we use the term “telescope geeks” lovingly because any of us who are devoted to our love of astronomy eventually become telescope geeks. And these are the type of people who will know exactly how to evaluate your needs in terms of where you are right now and where you want to go as your hobby grows with you. So if you have not yet associated with a local astronomy club, now is the time to do it. Start rubbing elbows with people who live and breathe telescopes. Their input is a hundred times more reliable than what a sales brochure or that salesman might have to say because the “telescope geeks” have been where you are, made the mistakes and are eager to help you avoid those same mistakes. Size Matters In the world of telescopes, the sales people see, to try to baffle us with all the bells and whistles of their hottest selling model. One of the big check points that is often pushed is the amplification level of the telescope lens. While that is a factor that is worth noting, when it comes to a telescope lens, the old phrase “size matters” is a good guideline. Just remember that your telescope lens works best when it takes in the most light it can from the object you are viewing. So the wider the diameter of the lens, the better a view you are going to get. So don’t fall for the amplification level only. Carefully evaluate the lens size so you have the right fit for what you want to do. It Has to Stand on Its Own Feet. If you are going to set up a permanent telescope station, then you can bolt the unit down so it is well supported. But many of us have to take our telescopes out into the country for optimum use. So the stand has to be strong and flexible so we can set up the telescope on uneven turf but still feel secure that this important and expensive piece of equipment is going to stand on its own without fear of it falling during our observation time. We already mentioned strong and flexible as evaluation guides for the telescope stand but add in ease of use as well. You have to be able to set your telescope up and break it down quickly and easily when you are on a remote viewing. You may even find yourself setting up or taking down your telescope in the dark or by lantern or flashlight if you are taking advantage of the great star displays in the late night sky that make this hobby so exciting. These are the basics of what to look for in your new telescope. Finally, make sure the telescope can be enhanced and expanded without having to throw the first unit away and buy something completely new. You want your telescope to grow as your knowledge and skills grow. If your first telescope meets all of these requirements, you are off on the right foot on a long and enjoyable career as an amateur astronomer. PPPPP 707
The Glossary of Telescopes When you enter into any new area of science, you almost always find yourself with a baffling new language of technical terms to learn before you can converse with the experts. This is certainly true in astronomy both in terms of terms that refer to the cosmos and terms that describe the tools of the trade, the most prevalent being the telescope. So to get us off of first base, let’s define some of the key terms that pertain to telescopes to help you be able to talk to them more intelligently. The first area of specialization in telescopes has to do with the types of telescopes people use. The three designs of telescopes that most people use are the Refractor, the Reflector and the Schmidt Cassegrain telescope. * The refractor telescope uses a convex lens to focus the light on the eyepiece. * The reflector telescope has a concave lens which means it bends in. It uses mirrors to focus the image that you eventually see. * The Schmidt Cassegrain telescope uses an involved system of mirrors to capture the image you want to see. * A binocular telescope uses a set of telescopes mounted and synchronized so your view of the sky is 3-D. Beyond the basic types, other terms refer to parts of the telescope or to the science behind how telescopes work. * Collimation is a term for how well tuned the telescope is to give you a good clear image of what you are looking at. You want your telescope to have good collimation so you are not getting a false image of the celestial body. * Aperture is a fancy word for how big the lens of your telescope is. But it’s an important word because the aperture of the lens is the key to how powerful your telescope is. Magnification has nothing to do with it, its all in the aperture. * Focuser is the housing that keeps the eyepiece of the telescope, or what you will look through, in place. The focuser has to be stable and in good repair for you to have an image you can rely on. * Mount and Wedge. Both of these terms refer to the tripod your telescope sits on. The mount is the actual tripod and the wedge is the device that lets you attach the telescope to the mount. The mount and the wedge are there to assist you with a superior viewing session and to keep your expensive telescope safe from a fall. * An Altazimuth Mount refers to the tripod of the telescope that holds the device in place and makes it useful during a star gazing session. The altazimuth mouth allows the telescope to move both horizontally (which is the azimuth) and vertically. In this way you have full range to look at things close to the horizon or directly overhead. * Coma has a different meaning than the one we are used to, and that’s a good thing. The coma is the blurry area on the outer rims of your view through the telescope. How big the coma is and to what extent it interferes with your viewing will have is important to the effectiveness of your telesscope. * Planisphere. A fancy word for a star chart. It is nothing less or more than a detailed map of where everything is in the cosmos and how to find the star you wish to study by keying off of known stars. * Barlow. This refers to a specialized type of lens that you can buy to enhance the magnification of your telescope. These are just a few of the basic concepts of telescope operation. We deliberately picked the ones you have to know to discuss telescopes intelligently. But your education into the more complex aspects of astronomy and telescope design and operation will go on for as long as you are a lover of astronomy, which we hope is for the rest of your life. PPPPP 670