Reaching for the unknown dark universe

Dr. Will Percival is a primary science coordinator for the Euclid space mission, set to launch from Cape Canaveral this July.

Percival is the Mike and Ophelia Lazaridis Distinguished Chair in Astrophysics, director of the Waterloo Centre for Astrophysics and a full professor in the Department of Physics and Astronomy.

As Percival explains, the Euclid satellite and the mission it will undertake are designed to solve a specific problem in astrophysics and cosmology. 

Theoretically, astrophysicists know that some 95 per cent of the universe is made up of what they call dark material, which is further split into dark matter (25 per cent) and dark energy (70 per cent). Only 5 per cent is regular material that we interact with day-to-day.

Dr. Will Percival hosted a public talk on the Euclid mission at Kitchener Public Library. Percival is the Mike and Ophelia Lazaridis Distinguished Chair in Astrophysics, director of the Waterloo Centre for Astrophysics and a full professor in the Department of Physics and Astronomy.

But because these dark materials do not interact through light, it is incredibly difficult to find and isolate them or their effects in a laboratory setting.

“We see the effects of dark matter and dark energy through astronomy,” Percival continues. “And we have models that help explain their properties. But scientifically, we don’t know very much about them at all.”

That’s where Euclid comes in.

Using different probes and instruments, the Euclid space telescope will precisely map a swath of the universe and allow astrophysicist to understand why it is expanding and accelerating. Dark matter and dark energy play a significant role in what astrophysicists call “large-scale structure” in the universe and how the universe has evolved over time.

Along with its primary mission, Euclid has several secondary missions. Because it is a super-high-resolution telescope, it will be able to provide the same kind of astounding images as the earlier Hubble telescope, but at an unimaginably larger scale.

“Euclid has similar resolution to Hubble, that level of imaging, but will cover 15,000 square degrees without needing to be focused on any specific objects,” Percival says. “We don’t need to point the telescope at particular objects, we’re simply going to observe everything within that area. We will then study huge reams of data and find new objects, not just get better detail on the objects that we already know are there.”

Dr. Will Percival at a public talk as part of outreach on the Euclid mission, hosted at Kitchener Public Library.

It will not be surprising, Percival explains, if Euclid discovers new classes of objects and produces unexpected results. The potential for new discoveries is huge. 

Along with the focus on science and discovery, Percival says that one of the most satisfying parts of the work he’s doing relates to outreach.

“Outreach is so important and it’s something I love doing,” he says. “Astronomy is a branch of science that a lot of people are interested in, and we usually have no problem filling the room when we do public presentations. It is a privilege to give back to the community and the public, who do so much to support our work.”

Percival says he’s especially keen to encourage young people who have an interest in space and astronomy.

“I encourage them to consider a career in the space sector. The scientific aspect, I think, is incredibly exciting. Even after hundreds of years there’s still so much about the universe we don’t know and so many new discoveries waiting to be made.”

Learn more about the Euclid mission through the European Space Agency (ESA) website.