How is your head now? Has your mind expanded faster than the speed of light? Surely you have a new sense of proportions, now that you have traveled back in time to the instant after the Universe came into being, and outward to the farthest reaches of the observable Universe, to the infant galaxies seen at nearly the beginning of time and even the stretched and cooled remnant radiation of the primordial fireball. Do you find yourself thinking about neighboring galaxies in the Local Group? When you look out your window at the horizon, do you ponder whether there is enough matter and energy in the Universe to flatten space-time?
Clearly these thoughts are out of this world. Your mind has been transported out of this world. You are now concerned with issues that a Citizen of the Galaxy would consider important. You are now committed to protecting and perserving intelligent life. You now see the myriad conditions that must exist for such a thing to develop. You now know that there are many worlds besides our own, and that we are part of a grand evolution of consciousness.
What will be your role in galactic society? How will you contribute to this great progression? What can you do here on Earth, in your own lives, that will enrich the Galaxy? These are the important questions.
Yes, there are lots of stars in our Milky Way Galaxy. Yes, there are lots of galaxies in our Universe. How many? The number is almost inconceivable. Does that make you feel small? Well, in one way everything about the cosmos, from the Earth to the Sun, the Solar System and beyond, makes us feel incredibly small, at least physically. How about mentally? Isn't the opposite true, in that the more we understand about the vastness of the Universe, the more connected and a part of it we feel ourselves to be? After all, our minds are wonderful components of this marvelous mix of matter and energy we call the Universe. We are able to think grand thoughts and comprehend these huge distances and spans of time through our mastery of mathematics and science. We are doing our part and taking our place in this wonderful world through our willingness and effort to learn about its ways and its means.
We can all agree that the bizarre and unusual hold a particular fascination in our consciousness, and that danger and disaster grab our attention. Certainly that has something to do with the public interest in black holes. What could be more sinister than an object that swallows up anything that gets too near, its victims never to be seen or heard of again? Shrouded in mystery and darkness, this monster both attracts and repels us, as if we were seated in a movie theater watching a horror flick.
Really, though, those monsters remain hidden and probably claim very few victims. True, there may be a black hole at the center of almost every galaxy, but compared to the hundreds of billions of normal objects, these denizens are extremely rare. Astronomers have direct evidence of only a handful of such objects in our galaxy. One look at the myriad stars that populate the sky on a dark night will convince you that the chances of a black hole jumping out of the bushes are almost nonexistant.
A far more mysterious substance may stalk our every move, though. Where is the dark matter that astronomers think outnumbers normal matter by a factor of at least 10 to 1? Do you have any better guesses after having studied it? Won't it be fun to keep tabs on the ongoing research into this tantalizing question? We are so lucky to be alive in this exciting golden age of astronomy.
Variable stars and stellar evolution were not part of the Medieval mind. Until recently, stars were considered eternal and unchanging. Now we know that they are dynamic objects, operating on a time scale of millions and billions of years. We can measure their pulsations on a human time scale, though. Some stars vary their output in just a few hours, and many change in a matter of days. Given the size of a typical star, that is pretty astonishing. Then there are the Mira variables, which dim to the point of completely disappearing from our view, changing brightness sometimes by a factor of 10,000 in a little over a year.
If these objects intrigue you, welcome to the club. They have captivated my imagination since my first astronomy class, and continue to amaze me with their variety. Want to be a part of it? Join the AAVSO and put your finger on the pulse.
Will we ever reach the stars? How will we do it? What could we learn from such a mission? These questions have intrigued people for centuries, but only lately has our knowledge of physics and astronomy given us the knowledge to contemplate making these dreams a reality. Perhaps the challenges are too great, the distances too far, the travel times longer than our civilization's lifetime. Just the fact that we have explored our own Solar System gives us hope, though. That activity, which started over 50 years ago with the Russians and their Sputnik satellite, has changed the human race, given it special status among all animals. When the United States sent astronauts to the Moon, homo sapiens crossed a boundary, expanded its habitat into the infinite reaches of space. How far we spread into that realm depends on how well we can understand and harness the secrets of matter and energy.
What was it that started humanity on such a journey? Some astronomers and social scientists suggest that the Moon may have played an important role in that process. The dramatic events where it eclipes the Sun and becomes eclipsed by the Earth caused many observers to wonder why that happened, prompting people to study the stars and planets, and construct explanations that could be tested by careful observation. Without that magnificent display of the motions of heavenly bodies, would humans have taken the trouble?