World Report: November 10, 1995 Vol.1 No.8
- This Issue:
- Table of Contents
- Cover Story
- Cover Story - Spanish Version
- Mini-Lesson
- Comprehension Quiz
- Teacher's Guide and Worksheets
Our Eye On The Universe
Take a good look at the photo on the cover. Are those towers of orange coral in an aqua sea? Or thunderclouds lighted by the setting sun? Not even close. This is no ordinary scene from Planet Earth.
The clouds in the picture are made of a gas called hydrogen. They are incredibly far from where you are sitting: 400 million times as far away as the sun is. They are also amazingly tall: 6 trillion miles high! (The earth is just 24,902 miles around at the equator.)
The purplish sparks you see are stars. But what really amazes scientists are the long, thin wisps sticking out from the clouds. Those are stars about to be born. When they get big enough (by gathering hydrogen), they will light up like a struck match and burn for billions of years.
Scientists have talked about the birth of stars for many years. But no one had ever seen it in action until this photo was released by nasa, the national space agency, last week. "I was just blown away," admits NASA scientist Ed Weiler.
The photo is just the latest of many mind-blowing pictures taken by the world's best eye on the sky: the Hubble Space Telescope.
Why Is The Hubble Special?
The Hubble telescope was put into orbit above the earth in 1990. Since then, it has sent home stunning snapshots from around the universe. The pictures have offered new information about how stars form and die, the age of the universe and many other mysteries. "The Hubble is fundamentally altering our view of the universe," says astronomer Rodger Thompson of the University of Arizona.
What makes the Hubble so powerful is its position above the earth's atmosphere. The atmosphere is a thick blanket of gas constantly swirling around our planet. The swirling is what makes stars seem to twinkle when we look up at night. But it also drives astronomers on earth crazy by blurring the view through their telescopes. The Hubble is above the atmosphere, so it gets a crystal-clear view.
It also sees certain kinds of starlight, called ultraviolet and infrared, that is blocked by the earth's atmosphere. All in all, the Hubble's view is 10 times sharper than any telescope's on earth.
Almost A Disaster
The Hubble's eye wasn't always so sharp. Shortly after a U.S. space shuttle placed the telescope in orbit, scientists discovered a terrible mistake. The big light-gathering mirror at the center of the telescope was the wrong shape. As a result, the pictures taken by the Hubble were fuzzy.
Solving the problem took brains and great courage. First a team of scientists designed a set of small mirrors to work like eyeglasses for the telescope. Then a team of astronauts had to install those eyeglasses and correct a long list of other problems with the telescope.
"I don't think anyone except for the astronauts themselves thought they could complete the mission," says Hubble scientist John Bahcall.
In December 1993, earthlings watched on TV as four space-suited astronauts struggled to fix the Hubble. They did it! Their success seemed like a miracle to astronomers all over the world. "We had a nonstop two-week party," says John Trauger. His team designed the new mirrors at the Jet Propulsion Laboratory in California.
Eye-Opening Views "Since then, the Hubble has performed perfectly. We can take pride in an achievement that no other nation could even consider," says astronomer Bahcall. NASA plans to make the Hubble even better. Shuttle astronauts will visit it in 1997, 1999 and 2002 to replace old parts with better equipment. "It's going to be a new telescope," says Ed Weiler, the Hubble's chief scientist.
Back when the space telescope was just a dream, many Americans wondered if it was really worth spending $5 billion on the idea. Today it seems like a bargain. Seeing the universe at work in all its glory is a miraculous treasure.
