MONTREAL – Maybe those science-fiction scenarios about killer robots from space invading the Earth aren’t so far-fetched after all.

Aliens bearing little resemblance to Steven Spielberg’s cuddly “ET” might actually eye Earth for its potential slaves and to plunder its natural resources, say scientists interviewed in “Aliens: The Definitive Guide,” a new documentary being broadcast Sunday on Discovery Canada.

In short, they might be a lot like humans were when they explored new lands.

But don’t go running for the shelters just yet.

Even if aliens are headed for us now, space travel can take thousands of years using currently known technology, which probably rules out the possibility of any malevolent ETs touching down during our lifetime, anyway.

Producer Alan Handel says aliens are a “never-ending preoccupation” for people, so making the documentary was a no-brainer. He says surveys indicate that many Canadians believe extra-terrestrials exist and may already have dropped in.

“I just think it’s a really neat concept to say ‘OK, let’s take it seriously and let’s go to some of the best scientific minds in the world and see what they have to say.’”

However, “Aliens: The Definitive Guide” isn’t a tale of extra-terrestrial terror and instead entertainingly poses an exhaustive list of questions about who may be beyond the stars.

What planets might have life? How might its inhabitants get here? What would they look like? And what are their possible intentions?

These are some of the queries pondered in the two-hour film by Montreal’s Handel Productions and U.K.-based Arrow Media.

A theoretical physicist at City University of New York scoffs at anyone who tries to suggest we’re the only life forms in the universe.

“Gimme a break,” Michio Kaku says in the documentary.

“I mean, how many stars are out there in the universe anyway? The Hubble Space Telescope can see about a 100 billion galaxies — that’s the visible universe,” he says. “Each galaxy consists of 100 billion stars. Do the math.”

For the benefit of viewers who might be a little less adapt at math than your average theoretical physicist, Kaku is kind enough to provide the tally: “10 sextillion — that’s one with 22 zeros after it.”

All the scientists agreed that any alien who touched down on Earth would be pretty advanced scientifically.

It’s not the first time Handel has tackled a subject that would be considered more in the realm of sensational supermarket tabloids. Their last definitive guide documentary was on Bigfoot and the next one in the works looks at time travel.

“We tried to have a lot of fun with it,” Handel says of the “Aliens” documentary. “There’s a playful tone at times.”

Handel describes himself as a “professional skeptic” when it comes to extra-terrestrial life and UFOs.

He says he was surprised by the number of planets that might support life in some form and the extent of the likelihood that alien life could visit Earth.

“It was really surprising to me. I had no idea. I think it’s a program that’s full of surprises and revelations and information that will be new to most viewers.”

He noted that science fiction can often cross the line into science fact, and pointed to one of his other previous films, “How William Shatner Changed The World.” That documentary discussed how some technology in the old “Star Trek” TV shows and movies had actually become real.

“A lot of stuff that seemed far-fetched back then was in fact really pretty visionary,” he said.

“It’s interesting to do a kind of reality check on science fiction and see how far away we are from that vision being real, or real down the road.”