Comets, Their Orbits, and Where They Hide!
Within the visible universe our solar system occupies a very local region of space. Sunlight reflected from the distant planet Neptune takes only 4 h to reach us here on Earth and yet we can also see quasars and gamma ray bursts whose light has taken up to 13 billion years to arrive. It may take our rockets a year or two to reach the planets but at least they can visit them within a time period that is short compared to our lifespan so we are seeing these objects in almost real time compared to everything else in the night sky. One added benefit of nearby objects is that they can drift against the background stars thereby adding an extra degree of reality and fascination to their study. Objects that move and change their appearance dramatically through a telescope are especially fascinating to us amateur astronomers. We all know that the Universe is a three dimensional place (and maybe even 11 dimensional if you are a string theorist!) but most of the time the objects in it look like they are fixed to a two dimensional star chart plastered on the sky a few miles above our heads. However, dramatic nearby phenomena are extra special and prove to us, if any proof where needed, that we are living in a solar system where absurdly large boulders orbit the Sun at incomprehensible speeds. Undoubtedly the most dramatic example of a rapidly changing spectacle in the sky is a total solar eclipse. Few who have seen one of these ultimate solar system alignments would dispute this; but unless you are on the narrow umbral track and have clear skies for those few minutes you will miss it!