© Carlos Osorio/Toronto Star
Sofi Papamarko, Joan Smith, Ryan Anning, Farrah Khan, Joshua Bowman, Egon Gardiner and Will Fox (left to right) pose for a photograph during Sofi's rapture party in Toronto on Friday night (May 20, 2011).
If the world were going to end today - as some Christian evangelicals insist - then chances are good that Qinya Liu would already have picked up on the signs.

As an assistant professor of geophysics at the University of Toronto, Liu understands the mechanics of the planet, but she doesn't seem inordinately concerned about fire and brimstone consuming her neighbourhood any time soon.

"I haven't seen in recent history any hazards that could wipe out life on Earth."

In Liu's view, there are five main mechanisms by which the planet could come to a sudden and sorrowful demise: Meteorites, volcanoes, earthquakes, nuclear wars and attacks by extra-terrestrials.

Liu doesn't believe that any of them is about to go critical: "I'm not writing my will yet."

Take that, Harold Camping.

He's the 89-year-old U.S. Christian evangelist who has been swearing up and down on American TV that the time of judgment will commence sharp at 6 p.m. on May 21.

It's then that the chosen will ascend bodily into heaven - in a mysterious manoeuvre known as the Rapture - leaving the rest of us saps to endure five months of excruciating suffering before our fine blue orb goes up in smoke around the end of October.

Liu, and other scientists, seem pretty confident things aren't going to turn out that way.

"The first hypothesis is a meteorite," she says. "It's a very small chance. It's basically a zero chance."

Granted, it has happened before.

Around 65 million years ago, a massive projectile crashed near Mexico's Yucatan Peninsula. Pretty soon, there were no more dinosaurs.

"The Earth does get hit occasionally by huge chunks of rock," says Pierre Savard, an associate professor of physics at the U of T, "and that could annihilate everyone on Earth. But, as far as we know, there are no rocks right now hurtling toward the planet."

Given that it would take a meteorite the size of mountain to threaten our extinction, and given that we can see to Pluto and beyond, we can scratch meteorites.


True, a massive volcanic eruption near Lake Toba in Indonesia is thought to have occurred around 70,000 years ago, causing a long ash-enshrouded winter that reduced the planet's human population to 10,000 individuals or so.

But that constitutes just one such eruption in the more than 100,000-year history of human existence. It could happen again. But, then, Rob Ford could also buy himself a bike.

Next up: earthquakes.

Several years ago, an American made-for-TV movie called 10.5 depicted the devastating consequences of a temblor on a scale vastly greater even than the earthquake that recently crippled much of Japan.

It doesn't seem beyond imagining that so colossal a convulsion could be just what Harold Camping has in mind - except for one thing: Earthquakes don't come that big.

"It turns out that's science fiction," says Liu. "Ten-point-five? It's not going to happen."

Surely nuclear war is a possibility?

As a geophysicist, Liu boasts no particular expertise in armed conflict. But she does follow the news and she doesn't think anyone at the helm of a nuclear power is unusually inclined to press the button just now.

"We've had much more severe global political standoffs before. I don't think we are in such a position now."

Which leaves . . . an invasion by aliens!

Once again, it could happen. But humans have spent decades monitoring the heavens in search of radio waves that might signal the existence of a highly developed species on some other planet.

So far: zilch.

"We haven't even observed anything remotely resembling an environment like the Earth's," says Liu.

Let's face it - warnings of the Apocalypse are nothing new.

More than 150 years ago, a U.S. Baptist preacher named William Miller predicted that the second coming of Christ would occur in 1844. Thousands of his followers quit their jobs and gave away their belongings in expectation of the glorious event.

It didn't happen, of course, and the result came to be known as the "Great Disappointment."

Camping himself formerly predicted that the world would end in 1994. He blamed errors in his math for getting it wrong. What he'll say Sunday is more difficult to predict.

"I think he has very little flexibility," says John Marshall, assistant professor of religion at the U of T. "Other members of the sect will have to face this personally. Some of them will leave."

None of them will be on hand when the world does, in fact, end - which it will.

In about 5 billion years, the sun will run out of hydrogen and begin to burn heavier elements, transforming its once balmy self into a Red Giant, whose gargantuan flames will consume this planet and everything on it.

As for the universe itself, scientists nowadays predict a less fiery but no less troubling destiny.

"It just gets worse and worse," says Savard, the U of T physicist.

The universe, it seems, will continue to expand at an ever accelerating rate, spurred on by a mysterious property called dark energy. Eventually, tens of billions of years from now, the stars will exhaust their fuel, and the entire cosmos will go dark. Yet still the galaxies will fly apart. Their expansion into the frozen void will never, ever end.

"Meanwhile," says Savard, "the forecast for Saturday is sunny."