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Bolometer Measurements Support Flat Universe Theory

JPL bolometers allow technologists to capture temperature variations of only 100-millionth of a degree (0.0001 C) in just a few seconds of observing time. The power from the cosmic microwave background, detectable by the sensors in one second of integration time, compares to the thermal radiation given off by a coffee maker at the distance of the moon.

By measuring one small patch of sky after another over several days of observation, bolometers can plot a map of the cosmic background radiation, providing a snapshot of the universe when the radiation formed about 300,000 years after the Big Bang. At this time, regions with a higher density of matter and energy left a record in the background radiation. Wherever dense regions existed, they left a faint imprint of slightly higher temperatures. These fluctuations in the background serve as a kind of fingerprint, allowing scientists to discriminate between theories of cosmic development.

Using advanced micro-machining techniques, each section of the bolometer's web - which looks like a classic spider web - was designed to be smaller than the millimeter wavelength of radiation streaming in from the cosmic microwave background. Created when the first atoms formed in the early universe, this cosmic microwave background has cooled a thousand times from its original temperature to the cold, faint radiation measured today.

Bolometers have been able to reveal density patterns in the young universe that are consistent with an inflationary theory of cosmic development. This theory proposes that, in the first moments after the Big Bang, the universe went through a period of extreme, exponential inflation. The theory further predicts a flat geometry for the universe, because the immense stretching of space during an inflationary period would have removed any initially strong curvature in the smaller and denser early universe.