1 Bringing the Night Sky Closer with Telescopes For thousands of years people looked up in amazement at the night sky They could see the moon and stars Even some planets were 44 visible But these objects were too far away to study In the early 1600s Dutch eyeglass maker Hans Lippershey built one of the first telescopes He used two glass lenses One was concave or curved inward The other was convex or curved outward Lippershey put the lenses in a tube That way he could look through both at the same time They made objects appear up to three times closer Italian astronomer Galileo Galilei heard of this new invention He built a telescope that magnified objects up to nine times He saw mountains and craters on the moon He noticed sunspots on the sun and made many other discoveries The first telescopes were refracting telescopes Their lenses bent and focused light to magnify objects But
Isaac Newton’s first reflecting telescope in the 1600s it was difficult to make good quality glass lenses Objects seen through early telescopes were often fuzzy In 1668 English scientist Isaac Newton built a reflecting telescope It used polished mirrors instead of glass lenses Light shined into the telescope and onto a concave mirror That light was then focused onto a smaller mirror The second mirror directed the light to an eyepiece Newton’s telescope magnified objects up to 35 times It made studying objects in the night sky much easier THINK ABOUT IT Hans Lippershey is credited with inventing the telescope But Galileo improved the telescope and made it more useful Who do you think deserves more credit for his work and why 1609 Year when Galileo built his first telescope Dutch eyeglass maker Hans Lippershey is credited with inventing the telescope Refracting telescopes use lenses to bend light and magnify faraway objects Reflecting telescopes use mirrors to focus light and magnify faraway objects 55
2 Making Rockets Fly Farther and Higher Rockets are devices filled with a combustible fuel When the fuel burns gases shoot out the rocket’s tail The force of these gases propels the rocket through the air Early rockets were fueled by Robert Goddard with his first liquid-fueled rocket in 1926 6 gunpowder or steam They were used for fireworks and weapons In the late 1800s Russian school teacher Konstantin Tsiolkovsky had a new idea He thought rockets could be used for space exploration But to reach space they would need a more powerful fuel Tsiolkovsky began researching the use of liquid fuels In the early 1900s American scientist Robert Goddard tested liquid-fueled rockets He used a mixture of gasoline and liquid oxygen On March 16 1926 he launched the first liquid-fueled rocket German scientist Hermann Oberth helped develop the idea of multiple stage rockets A large rocket could launch a smaller rocket into the air The speed of the larger rocket would then be added to that of the smaller rocket In this way rockets could travel farther and higher than ever before
Launch of a multistage Bumper-WAC rocket in 1950 German scientist Wernher von Braun studied under Oberth During World War II von Braun helped develop a multistage rocket called the V-2 It could reach the edges of space After the war von Braun worked for the United States military Using the V-2 design he helped build a multistage Bumper-WAC rocket In 1949 one of these rockets reached a height of more than 240 miles 390 km Many view this as the first successful space flight 200 Number of patents Robert Goddard received for his inventions Rockets are propelled by gases escaping from their tails Konstantin Tsiolkovsky first suggested using rockets to explore outer space Wernher von Braun helped build the first rocket to reach outer space 7
