Word: cosmos
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Unbeknownst to the duo, physicists at nearby Princeton University were about to turn their antenna on the heavens to look for that same signal. Astronomers had known since the 1920s that the galaxies were flying apart. But theorists had belatedly realized a key implication: the whole cosmos must at one point have been much smaller and hotter. About 300,000 years after the instant of the Big Bang, the entire visible universe would have been a cloud of hot, incredibly dense gas, not much bigger than the Milky Way is now, glowing white hot like a blast furnace...
...universe expands, the combined gravity from all the matter within it tends to slow that expansion, much as the earth's gravity tries to pull a rising rocket back to the ground. If the pull is strong enough, the expansion will stop and reverse itself; if not, the cosmos will go on getting bigger, literally forever. Which is it? One way to find out is to weigh the cosmos--to add up all the stars and all the galaxies, calculate their gravity and compare that with the expansion rate of the universe. If the cosmos is moving at escape velocity...
...wanted to measure the cosmic slowdown, known formally as the "deceleration parameter." The idea was straightforward: look at the nearby universe and measure how fast it is expanding. Then do the same for the distant universe, whose light is just now reaching us, having been emitted when the cosmos was young. Then compare...
...supernova known before, was far brighter than had been predicted. That neatly eliminated the idea of dust, since a more distant star should have been even more dust-dimmed than nearer ones. But the level of brightness also signaled that this supernova was shining when the expansion of the cosmos was still slowing down. "Usually," says Riess, "we see weird things and try to make our models of the universe fit. This time we put up a hoop for the observations to jump through in advance, and they did--which makes it a lot more convincing...
...lumps scientists saw were real, not some malfunction in the telescopes. And two weeks ago, astronomers from the Sloan Digital Sky Survey confirmed that this primordial lumpiness has carried over into modern times. The five-year mission of the survey, to make a 3-D map of the cosmos, is far from complete, but scientists reported at the American Astronomical Society's spring meeting in Pasadena, Calif., that it is clearer than ever that galaxies cluster together into huge clumps that reflect conditions that existed soon after the Big Bang...