A high-flying telescope

A massive helium balloon lifts equipment high into the atmosphere. This CMB sensor, hidden in the gondola below, is cooled to nearly absolute zero (-459 degrees Fahrenheit) to increase its sensitivity.
A massive helium balloon lifts equipment high into the atmosphere. This CMB sensor, hidden in the gondola below, is cooled to nearly absolute zero (-459 degrees Fahrenheit) to increase its sensitivity.
Courtesy Shaul Hanany

Because the CMB came from everywhere, it can be seen from anywhere. Or just about. The cosmic microwave background is only about 2.7 degrees Kelvin (-455 Fahrenheit)—very cold, and very faint. To observe it from Earth, without our atmosphere getting in the way, you have to get up high. Very high.

Shaul Hanany and his team put their equipment on a platform suspended from a huge balloon. From more than 100,000 feet above the ground, Hanany’s instruments were able to gather unique data on the intensity and polarization of the CMB.

Other groups have used balloons to observe the CMB, but Hanany’s project focused on a very tiny area—just .3 percent of the sky, near the constellation Draco—and produced some of the most detailed images of the CMB ever.

The shape of the universe

Using their CMB image, along with basic trigonometry (on a universe-sized scale), Hanany and his team were actually able to discover the “shape” of the universe. It can be a tricky concept to get your head around, but until few years ago scientists didn’t know whether our universe was flat, or curved or spherical. In a flat universe, just like on a flat sheet of paper, parallel lines remain parallel. In a curved space, parallel lines—like beams of light—would eventually cross or veer apart over a very great distance, like parallel lines of longitude on a globe. But because Hanany’s team knew the exact distance between two spots on their CMB map, and the distance from those spots to Earth (nearly the radius of the universe), they figured they should then know the angle between the radiation from those spots as they reach earth. If the angle was any greater or smaller than what basic trigonometry said it should be, then they’d know that light was converging or diverging; that the universe is curved. However, the instruments showed that light from the CMB was arriving at just the right angle, meaning that the universe is, in fact, “flat”; parallel lines will always stay parallel.