Dark Forces Dominate Universe
The earth, moon, sun and all visible stars in the sky make up less than one percent of the
universe. Almost all the rest is dark matter and dark energy, unknown forces that _________ (51)
astronomers.
Observations in recent years have changed the basic ________ (52) of how the universe
evolved and have indicated how little is known about the major forces and substances that
________ (53) our world. Astronomers now know that luminous (发光的) matter—stars, planets
and hot gas—accounts _________ (54) only about 0.4 percent of the universe. Non-luminous
components, such as black holes and intergalactic (星系间的) gas, ________ (55) up 3.6 percent.
The rest is either dark matter, about 23 percent, or dark energy, about 73 percent.
Dark matter, sometimes _________ (56) "cold dark matter", has been known for some time.
Only recently have researchers come to understand the key role it _______ (57) in the formation
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of stars, planets and even people.
"We _________ (58) our very existence to dark matter," said physicist Paul Steinhardt and a
co-author of a review on dark matter which ________ (59) not long ago in the journal Science.
"Dark matter dominated the structure _________ (60) in the early universe," Steinhardt said. "For
the first few billion years dark matter contained most of the mass of the universe. You can think of
ordinary matter ________ (61) a froth (泡沫) of an ocean of dark matter. The dark matter dumps
(结成块)and the ordinary matter falls into it. That ________ (62) to the formation of the stars and
galaxies (星系)." Without dark matter, there would be virtually no structures in the universe.
The nature of dark matter is ________ (63). It cannot be seen or detected directly.
Astronomers know it is there because of its ________ (64) on celestial (天体的)objects that can
be seen and measured. But the most dominating force of all in the universe is called dark energy, a
recently ________ (65) power that astronomers say is causing the galaxies in the universe to
separate at a faster and faster speed.