The U.S. space agency, NASA, is planning to launch a satellite that scientists hope will answer fundamental questions about the origin and destiny of our universe. (41) __________.
The prevailing theory of the universe's origin, the "Big Bang" theory, says all matter and energy were once compressed into a tiny point. The density and resulting temperature were so enormous that, about 13-to-15-billion years ago by current estimates, a mighty explosion flung the matter hurtling outward in all directions. (42) __________.They also ask, is the expansion accelerating? Will the universe collapse? What is its shape? Scientists will seek explanations with NASA's new Microwave Anisotropy Probe, abbreviated as MAP. (43) __________."MAP will take the ultimate baby picture, an image of the infant universe taken in the fossil light that is still present from the Big Bang," he says. "This glow, this radiation, is the oldest light in the universe. Imprinted on this background, physicists knew, would be the secrets of the Big Bang itself."
This background radiation is the light and heat that the early cosmic soup of matter emitted. Once roiling hot, it has cooled over the eons to just a few degrees above absolute zero. It was once thought to be distributed evenly. But in 1992, a highly sensitive NASA satellite named COBE detected nearly imperceptible variations in temperature as tiny as 30- millionths of a degree.
(44) __________."These patterns result from tiny concentrations that were in the very early universe that were the seeds that grew to become the stars and the galaxies that we see today," he says. "The tiny patterns in the light hold the keys for understanding the history, the content, the shape, and the ultimate fate of our universe."
(45) __________. Princeton University scientist David Spergel says MAP Will give us a much more accurate matter count than we have now. "Right now, we want to measure something like the matter-density of the universe," he says. "Today, we can estimate that to a factor of two. That's pretty good. What we want to do is be able to measure it to about the three-percent level, which is what MAP will be capable of doing."
To do its job, the $145 million MAP spacecraft will settle into an orbit 1. 5 million kilometers from the Earth. This is where the Earth's and Sun's gravitational pull are equal, and well past the range of the Earth's own obscuring microwave radiation.
While the older COBE satellite measured just a small part of the sky, Chalrles Bennett says MAP will scan the entire sky at 1,000 times better resolution. "The patterns that MAP measures are extremely difficult to measure," he says, "MAP will be measuring millionths of a degree temperature accuracies, and that's hard to do. That's like measuring the difference between two cups of sand to the accuracy of a single grain of sand."
[A] The principal NASA scientist for the New MAP spacecraft, Charles Bennett, says the heat patterns represent slight differences in the density of the young universe, where denser regions evolved into the present web of structures.
[B] NASA says the first results from the MAP mission will be ready in about 18 months after launch.
[C] The spacecraft will orbit the Earth seeking answers from an extremely faint glow of microwaves that have existed since the beginning of time.
[D] Scientists are trying to learn how it clumped together to produce stars, clusters of stars called galaxies, and clusters of galaxies.
[E] Astronomers are reporting evidence that points to a massive star-eating black hole at the center of our Milky Way galaxy.
[F] One of those keys is the amount of matter and its density. More matter with a higher density me, fins mole gravitational pull, suggesting a slowing of the universe's expansion, and perhaps even its collapse.
[G] The head of NASA's Evolution of the Universe program, Alan Bunner, says MAP will measure what is thought a remnant of the Big Bang--an afterglow of microwaves bathing the universe that was emitted by the ancient cosmic matter.