Dear friend of CIFAR,

Where I’m headed, the view is spectacular – I am trying to get a look at the Universe as it appeared a tiny fraction of a second after its creation. How is this possible? It’s not quite time travel, but it’s almost as good. In technical terms, we are looking at the polarization of the Cosmic Microwave Background radiation (the leftover energy of the Big Bang) and using it to detect gravitational waves. Astrophysicists like me are interested in gravitational waves because they carry information that we’ve never seen before about the cosmos.

Gravitational waves allow us to look at systems that are impossible to observe with optical and radio telescopes. These waves can permeate regions of space that light and radio waves cannot. They also distort space time, so they distort how distant things look. They allow us to investigate some of the biggest mysteries in the Universe, such as: Why did the Universe start out as uniform as it did? What caused its geometry?

Although gravitational waves have never been detected directly, researchers proved their existence indirectly by studying pairs of neutron stars (massive, dense celestial objects which form when a massive star explodes, and emit a stream of gravitational radiation as they orbit each other).

By looking at the CMB, we are basically looking as far away as one can possibly look. And because light takes time to travel, looking this far away takes us way back in time – 13.8 billion years back, to be exact.

The CMB is well-understood by Big Bang theory, which explains that the universe expanded from a hot and dense state at some finite time in the past, and continues to expand to this day. Inflation theory refines Big Bang theory by asserting that the universe initially expanded faster than the speed of light. This refinement predicts the release of gravitational waves, which may be large enough to leave a subtle but detectable imprint on the polarization of the CMB.

Studying a system as colossal as the CMB is a combined effort – it involves a combination of ground-based observatories, satellites and balloon-borne telescopes (which I design and build). One of the reasons I “gravitate” towards balloons is that they are relatively cheap, reusable and can be built quickly. One of my current experiments uses a balloon-based telescope we call Spider (named for the original shape of the apparatus). This experiment will employ the most sensitive equipment to hunt for the CMB signal. I hope to launch it this year.

Best wishes from the frontiers of human knowledge.

Barth Netterfield
Fellow, Cosmology and Gravity program
Canadian Institute for Advanced Research