Forget the Mayans. Here are 5 actual apocalyptic possibilities.

Asteroid Collisions and Global Warming More Dangerous than the Mayan Calendar

Nov. 28, 2012— -- It's pretty clear that the world will not end on December 21, 2012. At least not based on so-called Mayan prophecies.

A thousand years ago, the ancient Mayans predicted that on this date, the sun, the earth, and the center of the Milky Way will be perfectly aligned for the first time in 26,000 years, ending the "fifth era of the sun."

Their prediction about the sun´s position was right, according to modern scientists. Although some have also suggested that this "galactic alignment could lead to shifts in the world's magnetic poles" and generate solar storms that would cause all sorts of disasters on earth.

That is certainly not what the Mayans had in mind. In fact, anthropologist Carlos Payan argues that there are no clear indications that this civilization saw the end of the fifth solar cycle in 2012 as the end of the world. Not to mention, there are several other catastrophic possibilities with more potential to end the world than a supposed Mayan prediction. Here are five that would surprise even that ancient group.

1. Asteroid Collision

The first likely threat is a collision with an extraterrestrial object like a meteor, an asteroid or a comet. Most paleontologists say it was a 9-mile wide asteroid that crashed into what is now Mexico's Yucatan Peninsula that was responsible for the extinction of dinosaurs about 65 million years ago. According to NASA's Near Earth Object Program, there is some possibility that a 0.6 miles-wide asteroid collides with earth about every 100,000 years or so. A smaller asteroid with a diameter of 55 yards or so, could statistically hit earth every 100 years. Such an interstellar traffic accident might provoke acid rain that would impact crops worldwide and generate enough dust and debris to shield earth from sunlight.

2. Solar Flare

Another threat would be a solar flare, which could instantaneously knockout earth's power grid.

The sun works on 11-year cycles and when it reaches its "solar max", it generates "Coronal Mass Ejections," which are basically large bubbles of gas producing electromagnetic discharges that can mess with our highly interconnected electric systems.

According to NASA, a large sun storm could reach the earth in minutes and cause power failures that would leave 130 million people in the dark in the U.S. alone, and cost trillions of dollars in damage and take years to fix. A worst-case scenario might mean that international communications, transportation and trade would be cut off, and food supply would be disorganized. The next major period of solar storms could occur between 2012 and 2014.

3. Super Volcano

Not all apocalyptic menaces come from outer space. One credible threat is a "super volcano" that would spit out so much sulfur, carbon dioxide and ash that it would change the climate enough to alter the food chain and lead to human death.

Geologists have found traces of huge volcanoes around the world. One of them is actually under Yellow Stone National Park in Wyoming.

4. Killer Contagion

During the last century, the world has known four major flu pandemics, and the World Health Organization says it is inevitable for humanity to face another killer virus soon.

A few years ago Swine Influenza cost trillions in preventive action. Avian Flu, or Foot-and-Mouth Disease, generated waves of panic and revealed how vulnerable our interconnected economies would be to a new, super resistant virus.

5. Global Warming

2010 was the warmest year on record, with global temperatures 1.12 degrees Fahrenheit hotter than the average for the 20th century, provoking ever more volatile weather patterns and violent climate events like floods, typhoons, tsunamis and extreme blizzards.

As temperature rises, food will become scarce, air quality will worsen and diseases will spread. And as an investigation by the International Institute for Strategic Studies revealed, up to 65 countries are likely to lose more than 15% of their agricultural output by 2100. The World Health Organization considers that at least 150,000 people are already killed by climate-change related issues each year, mostly in the poorest countries.