美国英语听力80篇2 Lesson34
4. Exploration
Ancient Quasar
Astronomers have discovered what they say is one of the earliest known structures ever to form in the universe.
It is a star-like object called a quasar.
Quasars are very large.
They produce huge amounts of energy, up to ten thousand times that produced by our solar system.
Astronomers believe the energy of a quasar is produced by a huge black hole that attracts surrounding matter.
Several teams of scientists found the ancient object in the constellation Cetus.
The teams used two telescopes.
One is the Hale Telescope at Palomar Observatory in California.
The other is the National Science Foundation's 'telescope at Kitt Peak in Arizona.
Scientists at the Keck Observatory in Hawaii did a special study of the object's light.
Daniel Stern is an astronomer with NASA's Jet Propulsion Laboratory in Pasadena, California.
He played an important part in the recent discovery.
He says the distant object looked very much like a star.
However, study of the light from the object proved it to be a quasar.
He said further study showed the quasar is extremely old.
Tests showed that light from the object takes about 13,000,000,000,000 light years to reach Earth.
Scientists say that means the quasar existed at a time when the universe was less than 8% of its current age.
Tests of the red light from an object in space
can show how fast the object is moving away from us as the universe expands.
The faster it moves away, the more its light appears to be a red color.
Mister Stern says finding a quasar at that distance is like turning on a flashlight at the edge of the universe.
He says quasars act like very bright flashlights because they are brighter than distant galaxies.
He says this permits astronomers to study everything that has ever developed between Earth and the quasar.
Mister Stern says the newly discovered quasar will add to the knowledge
of how matter spread in the early history of the universe.
He says it also will help show how black holes,
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