Before 1957, we were limited to exploring space from Earth with telescope.
A telescope is a like a time machine. When you look through it into space, you not only get a close-up pictures of objects that ma be hundreds of millions of miles away-you
Also see deep into the past. That’s because light takes a long time to travel these huge distances-even though it’s whipping along at about 186,000 miles (300,00) per second! The sun light takes about eight minutes to make the 93 million mile (150 million km)
Trip to Earth. So you actually always see the Sun the way it looked eight minutes ago!
It works the same way with other stars-except now you’re talking years, not minutes.
Light from Proxima Centauri, the second closest star to us in our galaxy, takes four years to reach us.
Some of our telescopes are incredibly powerful. They see energy that was given off over 12 billion years ago! That’s when the universe was very young. Telescopes are helping us solve the mysteries of our universe-how it formed, if there are other life forms in it, and what’s going to happen to it-and to us-in the future.
Stonehenge:
Ancient peoples didn’t have telescopes, so they relied on their eyesight to study the sky.
They observed a lot this way. They picked out constellations among the stars and figured out the motion of the Sun and Moon. They also built stone structures that lined up with the different positions of the Sun, moon, and some times the stars. This is Stonehenge, built in England nearly 5,000 years ago.
Galileo Telescope
The Four biggest moons of Jupiter are called “Galilean” moons in honor of the first person to see them: The Italian scientist Galileo. Galileo spied these moons in 1610 using
A telescope he built himself. I t contained two lenses that focused light and made the things he looked at appear 32 times larger. It was called a refracting telescope. Galileo was also the first person to see the Moon’s mountains and craters.
Galileo’s discoveries made him famous, but they also got him into serious trouble.
Leaders of the catholic Church banned his books because they contradicted the church’s
teachings. The church taught that Earth revolves round the Sun. He was put under “house arrest” and had to stay inside his home until he died.
Newton’s Telescope:
Even though Galileo was not allowed to leave his house because of his ideas, he conducted to write. It’s a good thing he did, too. His books were read years later by the English mathematician Sir Isaac Newton and others. Newton is most famous for figuring out the law of gravity and what makes things move. In 1668, he invented a new kind of telescope, and it paved the way for the big reflecting telescope we use today.
Keck’s telescope:
Galileo and Newton would probably gasp at the size of our current telescopes, but these ‘scopes can probe very deep into space. The keck telescope and its twin, Keck II, are
gigantic. Each has a big mirror made up of 36 small mirrors and measures about 33 feet (10 meters) wide. They sit near each other a top an unlikely place: the volcano Mauna Kea in Hawaii. But the volcano is not active. An electronic link between the telescopes lets them function together as one giant telescope that sees light 14 billion years away.
Hard to believe, but there’s an even bigger telescope. It’s the Very Large Telescope (VTL) Chile. This humongous ‘scope includes four big telescopes and three smaller ones.
The mirror in each in one is 27 feet (8.2m) wide. In 2002, the telescopes will begin working together as one.
Telescopes in Space:
Big telescopes on Earth are great but they can see only so far. Their view is affected by Earth’s atmosphere , artificial light, and air pollution. To get really clear views of what’s out there, scientist are sending telescopes into space.
The most famous space telescope is the Hubble, which was launched from the space shuttle Discovery in 1990. It orbits Earth at a height of 370 miles (596) km. The Hubble has sent back amazing pictures – of Mars and other planets, exploding stars, nebulae, and
Galaxies as they appeared 10 to 12 billion years ago.
In July 1999, the Hubble was joined in space by the Chandra X-ray Observatory. This telescope “sees” x-rays given off by space objects that are billions of light years away. Photographic equipment and computers turn the x-rays into pictures for us. In fact, if your sight were as keen as Chandra’s, you could read a news paper headline just one-half-inch high from one-half mile away!!!!!!
