Balloon Experiments Map Creation's Glow
(From the July/August 2000 issue of StarDate magazine)
The universe is flat, dark, and filled with a mysterious energy that is causing it to expand faster, according to the results from two balloon-borne experiments announced this spring.
Called Boomerang and Maxima, the experiments studied the "glow" of the infant universe, just 300,000 years after the Big Bang. The glow is visible in every direction in the sky as microwaves, which can be detected by radio telescopes.
This "cosmic microwave background" glows at a temperature of 2.73 degrees Kelvin (–454 F). Tiny variations in temperature -- a few parts in 100,000 -- show dense regions of the early universe that gave birth to today's galaxies and galaxy clusters.
By measuring these variations, Boomerang and Maxima produced the most detailed maps yet of the infant universe, which reveal the geometry of the present-day universe. Their observations indicate that the universe is "flat" -- stretched out by a period of furious expansion shortly after the Big Bang.
Just as important, the experiments supported a single model of the composition of the universe: 5 percent normal matter and energy (visible stars and galaxies and all forms of electromagnetic energy, such as light); 30 percent dark matter, which produces no energy but can be detected through its gravitational pull on normal matter; and 65 percent dark energy, which appears to act as an "anti-gravity," causing the universe to expand faster.
Boomerang, which surveyed three percent of the sky, was carried to an altitude of about 23 miles (37 km) by a large helium balloon in late 1998. It was launched from McMurdo Station in Antarctica and circled the south pole for about 10 days. Maxima was launched on an overnight flight from Palestine, Texas, in August 1998. It surveyed a smaller region of the sky than Boomerang did, but its detectors are more sensitive. -- — Damond Benningfield
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