Apophis: killer asteroid bigger than thought

Lately it seems like the sky is falling. Comets and asteroids are cross-crossing the heavens above as meteors crash down on Earth. Last week there were two major events as meteors came down over central Russia and northern California. Scientists now say that a potential doomsday asteroid will soon pass near Earth, close enough to be visible to the naked eye.

LOS ANGELES, CA (Catholic Online) - Asteroid 99942 Apophis, or just Apophis for short, is on a course that will bring it perilously close to Earth in 2029. There is no question the shave will be close, almost as close as the one we received last week from Asteroid 2012 DA14. The pass will be so close, and Apophis so large, that an astute observer could potentially spot it from the ground without a telescope.

Apophis however, is a genuine killer. Unlike 2012 DA14, which had it hit would have likely vaporized in the atmosphere, Apophis is large enough to survive reentry and strike the surface with enough force to cause a massive tsunami should it land in the ocean, or tens of millions of deaths should it strike a populated area.

The impact would have the equivalent energy of about 510 megatons of TNT. That's much more than the largest atomic bomb ever detonated (Tsar Bomba at 50 megatons) and easily more than the Tunguska and Barringer impacts, between the 3-10 megaton range. In short, a collision with Apophis would devastate a large region of the planet.

However, it would still be far smaller than the Chicxulub event, which wiped out the dinosaurs. Scientists have thankfully ruled out any likelihood of an extinction-level event from Apophis.

Still, the asteroid is massive. Apophis is passing close to Earth right now, and researchers have discovered that it's 20 percent larger than previous estimates. The size of the asteroid has been revised upwards to 325 square meters.

They have also been revising their predictions regarding its orbit.

In 2029, Apophis will pass close enough to Earth to be easily visible to observers on the ground. It may even be visible to the naked eye as a point of light moving steadily across the background of stars over several minutes.

Then, in 2036, it may yet have a greater chance of impacting Earth. Although the odds remain miniscule, they are great enough that scientists have already predicted where it is most likely to land.

If Apophis hits in 2036, it could strike along a path that actually starts quite near the Urals where a meteor famously struck last week. That path then continues across Siberia and into the Pacific near Hawai'i. The danger zone crosses Central America in Nicaragua, and brushes the northern coasts of Colombia and Venezuela. The danger zone ends just off the western coast of Africa.

Odds are, the impact will strike the ocean, creating a devastating tsunami that could kill millions.

Fortunately, the odds are strong that it will miss in 2036.

But what about beyond that? Scientists aren't so sure. Apophis has probably been in its dangerous orbit near Earth for thousands, perhaps millions of years. Or, it could be a new arrival, its current, dangerous orbit only decades old. That much is impossible to tell. Regardless, sooner or later, it seems Earth will have a date with Apophis.

When that happens, we can only hope that scientists and governments around the world have a plan in place to protect us, and the ability to use it. Meanwhile, the rest of us will watch and wait, albeit a bit nervously.

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