Debunking the doomsday scenarios

The means by which we meet our end in 2012 vary depending on the book read, website visited or movie seen. Here are five popular scenarios:

Threat: Planet alignment. The Mayan calendar ends as our solar system aligns with the center of the Milky Way. Some who study the Mayans say that means catastrophe.

Science says: There have been any number of speculations and outright hoaxes about planetary alignments. Any alignment of planets will have no effect on Earth.

Threat: Planet X, a space object that is thought to travel through our solar system every 26,000 years, returns. A flyby means hurricanes, volcanoes and debris colliding with Earth.

Science says: The search for Planet X has a wonderful history in our culture, but Planet X doesn't exist.

Threat: Magnetic pole reversal. The polarity of north and south changes places, and the magnetic field protecting Earth weakens. Compasses won't work, bird migration is foiled. Solar radiation heats the Earth's surface and disrupts the electrical grid. In other words, it'll be really hot just when air conditioners won't work.

Science says: If there is pole reversal, there will be some changes in the magnetic field, but it will primarily affect space around the Earth. Humans have already lived through a number of pole reversals. We'll survive the next one.

Science says: Solar activity or sun spots are cyclical. The next cycle just began, and it will peak around 2012 to 2013. Then there will be a quiet period. It happens every 11 years. There might be some disruptions in communications, but there's no disaster coming.

Threat: Polar shift, not the same thing as pole reversal, occurs when Earth's molten lava core actually shifts, changing the Earth's axis of rotation and resulting in crustal displacement -- oceans run amok over land, volcanoes explode and there are earthquakes everywhere.

Science says: The history of Earth has been a violent one: plates smashing together and ripping apart, volcanoes and earthquakes. These are all natural and go on all the time.

Information from "The Complete Idiot's Guide to 2012" and Prof. Lawrence Rudnick, School of Physics and Astronomy, University of Minnesota.