ASTRONOMY UNDERSTANDING CELESTIAL BODIES the advent of spectroscopes radio telescopes and observatories in Earth orbit and many other technological advances It takes a quick tour of the universe starting with our Earth's solar system then moving out into Earth's galaxy the Milky Way where other worlds orbit other stars and finally into intergalactic space and the billions of galaxies stretching to the unimag inably distant edge The book explains some of the strangest denizens of the celestial zoo from black holes so massive that nothing can escape their grav itational pull not even light to quasars that can shine more brightly than entire galaxies full of stars to the mysterious dark matter that affects the structure of the universe and yet remains an almost complete unknown The book concludes with the quest to answer some of the most fundamental questions science has ever faced how the universe was born how it has evolved and what its ultimate fate will be and how that quest has led to one of science's most famous theories even lending its name to a popular television show the big bang theory Scientists know far more about the uni verse and Earth's place within it than the 10
INTRODUCTION ancient people gazing up at the star spangled sky could have hoped to understand Ancient peoples made up stories based on the con stellations they saw in the night sky Today there exist actual photographs of space taken from a satellite Modern astronomy is said to have begun in the early sixteenth century Since then scientists have discovered so much about the universe Yet there is still so much more to learn Astronomy's most excit ing discoveries may well remain to be made 11
CHAPTER 1 THE BASICS OF ASTRONOMY ne of the oldest of all sciences is astronomy the study of celestial objects That s not too surprising since people have been looking up at the skies since before recorded history and peo ple who view dark skies quickly recognize that some of those points of light follow paths that are orderly and predictable Even though astronomy is one of the oldest sciences new discoveries continue to flood in from modern day astronomers Today of course astronomy has moved beyond merely observing the Sun Moon stars and planets from Earth s surface Today astronomy encompasses the study of everything outside our atmosphere from our solar system to the stars of our galaxy to all the millions of galaxies in deep space New technology new theo ries and new observations are leading us to ever more exciting insights into the astonishing complexity and diversity of Our universe 12
THE BASICs OF ASTRONOMY ASTRONOMY THROUGHOUT TIME The ruins of many ancient structures indi cate that their builders observed the motions of the Sun the Moon and other celestial bodies The most famous of these is prob ably England s Stonehenge which was built between about 3100 and 1550 BCE Some of the monument s large stones were aligned in relationship to the position of the rising Sun on the summer solstice Several hundreds of 11 1 The positioning of the stones in the prehistoric monument Stonehenge indicates that the site was used by ancient peoples to track the movement of the Sun and Moon George W Bailey Shutterstock com 13
