HALIFAX -- An unusual, solar-powered boat could be the key to unlocking secrets of the sea and climate change, say researchers who've been zigzagging the waters off North America's east coast for more than a month.

The MS Turanor PlanetSolar made its first Canadian stop this week when it arrived in Halifax as part of an expedition across the Atlantic Ocean and along the Gulf Stream.

"It's very exciting science that we're conducting," Jerome Kasparian, one of four researchers aboard the vessel, said Thursday.

At 35-metres long, PlanetSolar is billed as the biggest solar boat ever built and is powered exclusively by the sun.

Since its arrival in Halifax, crowds of curious passersby have gathered to get a closer glimpse of the Swiss-owned, German-built catamaran, which boasts 520 square metres of shiny solar panels on its sun deck.

"It's incredible. I've never seen anything like this before," said Trent Perrott, 55, who stopped along the waterfront to look at the vessel.

"I've never seen solar power used to this extent."

The boat sits on large floaters, making the hull appear as though it's hovering over the water's surface and lending to its futuristic, UFO-like appearance. The solar panels charge batteries stored in the floaters which, in turn, power the boat's electric motors.

On board are five crew members and four researchers, who are collecting data in hopes of better understanding the interaction between ocean and atmosphere and how that affects climate change.

All but one of the researchers, including Kasparian, are from the University of Geneva in Switzerland. The other researcher is from the Woods Hole Oceanographic Institute in Massachusetts.

The team is focusing their efforts during the 8,000-kilometre trip on the study of ocean eddies -- large, swirling vortices that affect heat exchanges with the atmosphere and phytoplankton growth.

Most importantly, working aboard the vessel allows the researchers to gather data that's untouched by emissions.

"It has no diesel propeller, which prevents any self-made pollution," said Kasparian, a researcher in applied physics.

"And at the same time, it's a motor ship so we can control the trajectory and choose with quite a lot of flexibility where we want to go."

Plus, the eye-catching boat allows Kasparian's team to sail in style.

"This ship is pretty impressive. First of all, it's quite large and its look ... is quite unique. It's very fascinating, like an alien vessel."

The vessel was built about four years ago and in May 2012 completed the first solar-powered trip around the world in 584 days.

The latest voyage began in March in France. The vessel has also made stops in Miami, New York and Boston along the way to Halifax.

Its French-born captain, Gerard d'Aboville, is no stranger to the sea.

The sailor has conquered both the Atlantic and Pacific oceans as a solo rower.

But d'Aboville said nothing compares to navigating a boat that runs on rays.

"We have to be careful, we have to try to avoid places where there are clouds as much as we can, of course," he said. "We have to be careful with the management of energy."

It takes about one day of full sun to recharge the batteries. The boat's solar panels also expand from the sides of the boat to a width of 23 metres to allow for maximum sun exposure.

If required, d'Aboville said the vessel can run on battery power alone at a reduced speed for about three days.

That might be necessary -- the boat is scheduled to depart next week for the frequently foggy city of St. John's, N.L.