Telescope in Outer Space - Hubble Space Telescope 

Pillars of Creation.Source of pictures: NASA Official Website

The vacation was almost over. Dad took Daniel to the planetarium to see the latest exhibition. Daniel was totally amazed by the gorgeous pictures there, thinking how cool it is to be an astronaut. They could see so many beautiful sceneries every day. One of Daniel's favorites was a photograph calledPillars of Creation. He stood in front of the photograph for a long time, holding Dad's hand. According to the tag below,the photograph was taken by the Hubble Space Telescope. Daniel looked up and askedDad, 'Where is the Hubble Space Telescope? Can we take a look?"

Dad looked at the photograph and said, "Hubble is special. It is a telescope floating in the outer space and the first space telescope created by human beings."

Daniel didn’t get it. Why put the telescope in space?

"Observation of the universe from the earth is constrained in many ways," Dad continued, "The biggest constraint is the atmosphere. The atmosphere can insulate most of the cosmic radiation, protecting lives on the earth, but for astronomers, especially those who keep continuous observation of the sky in front of telescopes, the atmosphere is like a mirror with condensation on it. Think about how you feel when you look in the mirror after taking a bath. When the mirror was fogged, people could not see clearly. The atmosphere deflects light from the universe, causing us to lose track of where it comes from. There is no air in space, which is like a clear mirror, so the telescope there can take such beautiful pictures. But that's not what the universe really looks like. This is the image from the telescope that scientists have superposed and enhanced with computer. It’s definitely not what you can see in space."

Daniel was a little disappointed. It turned out that scientists also mislead people with 'fake' pictures.

Dad seemed to like this photograph very much, and he stared at it quietly for quite a while. Daniel had just decided to look elsewhere when Dad said, "This is the most wonderful thing about space. Human have been trying to explore the mysteries of the universe. They’ve been trying to see, hear and imagine what the universe is like in its early stage. No one knows the answer, but images taken by the telescope can serve as evidence for scientists to prove their viewpoints. Telescopes can catch light that is far away and we can never see in our lifetime. They are really 'the eyes of heaven.'" Daniel seemed to share Dad’s infatuation with the picture.

Dad continued, "In space, the moon is the nearest celestial body to the earth. It's earth's only natural satellite. The moon revolves around the earth in the way as the earth revolves around the sun.But it takes about 29 days for the moon to make one revolution.The sun is a giant hot air balloon, and its light takes 8 minutes to reach the earth, so the sun we see on earth is not the one in real time, but the sun eight minutes ago. Do you know how many galaxies there are in the universe?"

Daniel shook his head, and Dad continued, "Scientists estimate that there are 100 billion to 200 billion galaxies! We are in the Milky Way galaxy, with hundreds of billions of stars and a diameter of about 100,000 light-years. Outside the Milky Way, we can only see three galaxies with naked eyes, including theMagellanic Clouds and the Andromeda Galaxy."

Daniel looked up at Dad curiously and asked, "Where can I see these galaxies?"

"I'll show you next year." Dad finally moved away from thePillars of Creation.

Author: Huang Jing