Then came the telescope Beginning in the early 1600s astronomers were able to view cosmic objects close up The enlargements were not at all great by modern stan dards but they were astonishing at the time New knowl edge helped correct and clarify old notions about how the universe functions Telescopes were steadily improved and new tools were introduced The first successes in actually probing the heights occurred more than two hundred years ago Experiment ers first leveraged wind power to fly kites Beginning in the 1780s balloons filled with hot air or lighter-than-air gases such as hydrogen and helium were sent higher and higher into the skies The first piloted balloon flight was made in 1783 The great breakthrough in the quest to explore space was the invention of the powered airplane in the early twentieth century After that the ultimate objective of space scientists was tantalizingly within reach manned flights above Earth’s atmosphere 6 the early days of spaCe exploratIon
What’s Up there The earliest humans gazing into night skies dotted with white specks must have wondered What’s up there Every generation since then has asked the same question Over the centuries dedicated astronomers have accumulated an immense body of knowledge about the solar system and the immeasurable space beyond Still they probe New discoveries are made every day It is obvious though that the puzzle of the stars can never be completely understood When studying the universe questions that are finally answered present new mysteries EARLY ASTRONOMERS The earliest sophisticated astronomy arose in ancient Baby lonia Babylonian scholars believed the universe existed on six levels The surface of Earth was one level the visible stars above it another level They believed two additional levels of heaven existed above the visible sky and two underworlds existed beneath Earth’s surface 7 Chapter tItle runnIng head goes here Chapter 1
A stone tablet more than two thousand years old preserves records of Babylonian sky watchers observations of the planet Venus 8 the early days of spaCe exploratIon
What’s up there The powerful Babylonian civilization was centered in what is now southern Iraq during the eighteenth to sixth centuries BCE Although their conception of the universe proved wrong they contributed to the science of astron omy They made detailed records of the positions of promi nent heavenly bodies and devised calendars based on their observations The ancient Greeks were not as advanced in astronomy as the Babylonians They made a breakthrough THE FIRST PREDICTIVE SCIENCE Using night-by-night observations recorded over many years ancient Babylonian astronomers achieved the ability to predict the behavior of the moon and the planets Their work was important in the develop ment of astronomy as one of the earliest sciences The Babylonians also applied their observations to a pseudoscience astrology Astrologists believe that the motions and positions of celestial objects affect events on Earth The Babylonians studied the skies largely because they thought the gods sent signs from heaven to warn the king about such events as impending war a bad barley harvest or an impending epidemic Most scientists scoff at astrology But until recent centuries astrol ogy was considered part of astronomy Astronomers advised nobles of coming events based on astrological calculations The scientists might not have believed in astrology themselves but they needed the money they were paid 9
