'Doomsday Asteroid' Apophis misses Earth by a few million miles

(Florida Today) -- Near Earth Objects are comets and asteroids that cross the Earth's orbit and represent a potential threat of hitting the Earth. Soon after its discovery, an asteroid provisionally named 2004 MN4 was nicknamed "The Doomsday Asteroid," when initial predictions gave it a 2.7 percent chance of striking Earth in April 2029. This elevated it to Level 4 on the Torino scale, the highest ever recorded.

Level 4 is described as, "A close encounter, meriting attention by astronomers. Current calculations give a 1 percent or greater chance of collision capable of regional devastation. Most likely, new telescopic observations will lead to re-assignment to Level 0: "Attention by public and by public officials is merited if the encounter is less than a decade away."

The "regional devastation" comes from the fact that the asteroid was estimated to be around 300 meters in diameter, capable of producing huge tsunamis if there were an oceanic impact. Now 2004 MN4 is rated a 0 on the Torino scale, since the uncertainty of its orbit has been reduced, making a more precise prediction possible.

The provisional name, 2004 MN4, has since been replaced by a permanent name (99942) Apophis. Apophis is the Greek name of an enemy of Ra, the ancient Egyptian sun-god. Otherwise known as Apep, the Uncreator, it is an evil serpent that tries to swallow Ra during his nightly passage through the eternal darkness of the Duat.

The (99942) - with the parentheses - designates Apophis as the 9,9942nd asteroid to have its orbit registered with the Minor Planet Center (MPC).

The MPC operates at the Smithsonian Astrophysical Observatory, under the auspices of the International Astronomical Union (IAU). The MPC is responsible for the designation of minor bodies in the solar system: minor planets and comets among others. There are now more than a third of a million and counting, due to recent extensive computerized surveys. Having a permanent number made it eligible for naming. Most of the recently discovered asteroids will probably never be named.

Apophis made its closest approach to Earth on Wednesday, but was visible only through telescopes at a distance of about 9 million miles, a little less than one tenth of the distance from Earth to the Sun.

It caught the attention of the orbiting Herschel space telescope.

This time Apophis was slowly cruising past the background stars, at a barely discernible rate. When it returns in 2029, Apophis will be much closer; passing within 22,300 miles of Earth's surface - closer even than the orbits of the geostationary satellites that will be bringing news of the interloper to receiver dishes all over the world.

Though we are very certain that Apophis will miss the Earth in 2029, there still remains a small chance that Apophis will pass through a "keyhole" where the Earth's gravity will exactly bend its orbit into a new track leading to an impact with Earth in 2036. However, the probability of an April 13, 2036 impact is considered to be 1 in 7,143,000. Lay your bets!

At the planetarium

Brevard Community College Cocoa Campus is the site of the Astronaut Memorial Planetarium and Observatory. The observatory telescope is free for public viewing, and is open from 6:45 p.m. to 10:15 p.m. (approximately) on Friday and Saturday evenings.

The Planetarium and the Discovery Theater are ready to entertain you with shows at 7, 8 and 9 p.m. Friday and Saturday.

On Friday, BCC will show "The Planets" in the planetarium, naturally, followed by "Tropical Rain Forest" in the Discovery Theater (IMAX). At 9 p.m. get into Led Zeppelin back in the planetarium theater where the laser beams will cut through the haze.

Saturday shows are "Amazing Universe," "The Living Sea" and "Pink Floyd: Dark Side of the Moon."

Visit www.brevardcc.edu/planet/ for show descriptions, schedule details, ticket prices, and directions to the Planetarium. Or you may call the box office at (321) 433-7373 for prices and directions.