Keith Vanderlinde’s South Pole Telescope is perfect for cosmic sleuthing
by Sharon Oosthoek

Perched on a frigid patch of snow at the South Pole, a 10-metre diameter telescope is scanning the heavens for the oldest light in the universe. The image created by this light can be read like a blueprint that shows how ancient gases first coalesced into clusters of galaxies.

Those who know how to read the blueprint — including U of T cosmologist Professor Keith Vanderlinde — are using the South Pole Telescope to reveal no less than how the universe formed and evolved.

“That light has been travelling toward us since shortly after the Big Bang,” says Vanderlinde. “In cosmology, distance is time. This stuff is coming from the edge of the observable universe. It’s the oldest light there is.”

The light he is talking about is known as Cosmic Microwave Background and is left over from the rapid expansion of the universe some 13.8 billion years ago. Because microwave light has a longer wavelength than visible light, we can’t see it.

But the South Pole Telescope can.

Situated just outside Antarctica’s Amundsen-Scott South Pole Station, it captures an image of the sky with an array of extremely sensitive thermometers that register miniscule changes in temperature. These temperature changes are a reflection of how much microwave light is hitting the telescope.

Vanderlinde is particularly interested in how the light is changed when passing through and around clumps of gases in the midst of forming galaxy clusters. These changes provide a blueprint of the unfolding universe.

“It allows us to place ourselves in context — to know where we live,” says Vanderlinde, who has plans to make the telescope even more sensitive. His Long Wavelength Lab at U of T’s Dunlap Institute is helping develop its next-generation upgrades.

The telescope’s South Pole location is ideal for cosmic sleuthing. Microwave light is absorbed by water, but the extreme cold means the atmosphere contains next to no water.
Yet that cold, dry air means the telescope needs a 24/7 babysitter.

“It can get as cold as -75C and everything breaks at that temperature and in the extreme dryness,” says Vanderlinde. “Anything that moves or is electrical has the potential to fail, and it happens quite frequently.”

In 2008, Vanderlinde pulled an 11-month shift, keeping the telescope in optimum working order. He and a fellow researcher took turns sleeping and keeping an eye on their charge.

Not that he minded, given what’s at stake: “We are pushing the frontiers of physics,” he says. “We are trying to understand the fundamental laws that underlie everything.”

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