Frozen secrets

Over the past five years, thousands of detectors have been carefully embedded into holes 1.5 miles deep to try to understand everything from cosmological events that release powerful bursts of energy to a mysterious form of matter that makes up far more of the universe than the stuff people interact with each day.

“We humans, ever since we became conscious, looked up at the sky and wondered what we were seeing,’’ said Gary Hill, an astrophysicist at the University of Wisconsin Madison who works on the experiment, called IceCube. “You can imagine a cave man coming out of the cave and wondering what stars were.

“We’re figuring it out piece by piece. This is another step in a line of research understanding what the universe is, where it came from, and, ultimately, why we’re here.’’

To detect the signatures of the particles called neutrinos, researchers decided to take advantage of a spot with large volumes of exceptionally clear ice: the polar ice cap.

The ice must be clear because the researchers are looking for light that is given off after neutrinos interact with other particles. Scientists also need a big detector because neutrinos rarely interact with other tiny particles.

So ethereal are neutrinos that John Updike wrote about them in a poem:

The earth is just a silly ball To them, through which they simply pass, Like dustmaids down a drafty hall . . . Researchers built about 5,000 spherical modules that can detect the flash of light created when a neutrino interacts with a component of an atom in the ice.

Each module draws on Bay State products: 21 electronic components from Analog Devices Inc., a Norwood company that makes semiconductors and chips for everything from digital cameras to the telecommunications industry. And glass balls that house the modules from Teledyne Benthos, a Falmouth company that makes equipment for use in remote environments.

“Data converters sit at the interface of real-world analog signals . . . and digital signals we feed into computers,’’ said David Robertson, a vice president at Analog Devices. “This is a classic example of the kinds of interesting places where these converters turn up.’’

Embedding the modules deep in Antarctic ice is a difficult task.

Researchers use hot water to drill 1.5 miles into the ice, which takes about two days. Then, they lower a cable strung with 60 modules into the holes.

Researchers must have the cable in place within about a day, because the water freezes quickly around the modules, and they become inaccessible for repairs.

Analog Devices’ chips process pulses from the light sensors, digitally record the signals, and transmit them to the surface.

“We have this situation where we have to reliably communicate over a pretty wide range of distances,’’ said Perry Sandstrom, a University of Wisconsin electrical engineer. “This array is spread out over a large area and a large volume.’’

The glass spheres made by Teledyne Benthos need to withstand the intense pressure of being lowered into a mile and a half of water, and then frozen.

Researchers are planning to complete the installation of the last seven strings of modules this coming Antarctic summer. When finished, the detector will have 86 strings over about 250 acres.

Already, the detector is looking for high-energy neutrinos, and researchers are hoping to answer some basic scientific questions.

In the 1960s, when the US government was launching spy satellites to ensure the Russians were not conducting nuclear tests, they inadvertently spotted brief but incredibly powerful bursts of energy from space. These gamma-ray bursts put out about 100 times more energy in a few seconds than the sun will in its entire lifetime.

Researchers think they may be created in events that also create the cosmic rays that shower down on the Earth — and may let loose a flood of neutrinos.

Using IceCube, researchers hope to detect neutrinos and better understand the origins of these violent cosmological events.

They also hope the telescope can accumulate more evidence about dark matter, a mysterious type of matter that, according to widely accepted theories, makes up about 23 percent of the universe.

The researchers are trying to answer basic questions about the universe, but for the companies whose products are involved, the remote environment and extreme conditions are just more tests of their equipment.

“Those things are permanently embedded in the ice forever,’’ Sandstrom said. “This is a high-reliability application. . . . It’s about as unfixable as it gets.’’

Carolyn Y. Johnson can be reached at cjohnson@globe.com.