A strange yellow glow emanating from the southwestern portion of Toronto has drawn many quizzical and even worried reactions on social media over the last month or so.

On foggy nights, the eerie yellow haze can encompass a huge portion of the city's sky and looks much like the lighting effects from Close Encounters of the Third Kind.

Giant fire on Lake Ontario or what? pic.twitter.com/6aH0drJcul

— sean andernacht (@seanandernacht) February 25, 2017

Even on clear nights, the glow can be spotted from condos and apartment buildings from a surprisingly large swath of Toronto, though it's much easier to pinpoint the source on such occasions.

There is a strange glow over the lake SW of downtown Toronto. It's kind of freaking me out. And no I'm not drunk or high.

— Adam Taves (@ataves) March 20, 2017

As much as I'd love to report that Toronto is regularly being visited by aliens, the answer is a bit more down to earth, or turf, if you will. The bright yellow glow comes primarily from the grass growing lights at BMO Field.

The stadium has solicited the services of SGL (Stadium Grass Lighting) to keep its turf in the best shape possible. With both Toronto FC and the Argonauts using the field, it's one of the busiest natural grass surfaces in North America that's not used for baseball.

A post shared by Robert Peacock (@robertpeacock22) on Feb 24, 2017 at 3:52pm PST

The reason the glow we see at night is yellow/orange is that the special lights they use to accelerate grass growth are meant to mimic the sun's rays, which makes a whole lot of sense when you think about it.

Chatter about the glow has increased since late February as efforts ramp up to prepare the field for the upcoming season. TFC's home opener against Sporting Kansas City takes place on March 31.