Pictures in the Sky

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.

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.

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