Our asteroid was given the name of “2012
DA14” as a “minor planet designation.” Formal minor planet designations are number–name
combinations overseen by the Minor Planet Center,
a branch of the International Astronomical Union. Designations are used for dwarf planets and small solar system bodies such as asteroids.
2012 DA14’s approach will be the nearest
known flyby for an object of this size. Astronomers
assure that it will not strike Earth, and also assure that nothing will
happen when it passes, no alteration of tides, no volcanic eruptions. "No Earth impact is possible,"
Donald Yeomans, manager of NASA's Near-Earth Object program at the Jet Propulsion
Laboratory in Pasadena CA, assures us. Even
the chance of an asteroid-satellite run-in is extremely remote. "No one
has raised a red flag, nor will they," Yeomans told reporters. "I
certainly don't anticipate any problems whatsoever."
This also marks the first time such a close passage has been known about a year in advance. We will not get another pass of 2012 DA14
until February 2046 when the asteroid misses us at twice the distance of
the moon.
The closest approach of 2012 DA14 will
occur Friday afternoon over Indonesia. The
asteroid will be invisible to the naked eye, and even with binoculars and
telescopes will appear as a small point of light. The prime viewing locations will be in Asia,
Australia and Eastern Europe. It will
approach Earth from “down under,” and be straight overhead for observers in the
pre-dawn hours located in western Indonesia. Australia and eastern Asia will have a shot at
seeing the asteroid as it whizzes through the sky in the early morning hours.
Observers in western Asia, Africa and Europe will see the asteroid lower to the
east on the night of the 15th.
In the United States, astronomers using NASA's deep-space antenna in
California's Mojave Desert will have to wait eight hours after the closest
approach to capture radar images.
Now what is the basic nature of this
object swinging so closely to our planet?
Asteroids are also known as "minor planets.” The four largest asteroids known are
spherical or ball-shaped, like the Earth, and have diameters of between 100 and
500 miles. In comparison to Earth's
moon, which has a diameter of about 2100 miles, even the largest asteroids are
still small. The remaining asteroids range in diameter all the way down to less
than five miles. Asteroids with
diameters of thirty miles or less no longer have a spherical shape. Most asteroids orbit the Sun between Mars and
Jupiter. Although some asteroids have
sizes comparable to some moons in our solar system, these are not moons because
they only orbit the Sun, and not planets. The largest asteroids are called planetoids. Most
of our solar system's asteroids are located between the orbits of Mars and
Jupiter, and have remained there for billions of years. Some occasionally visit Earth's neighborhood.
The flyby of 2012 DA14 highlights the
need to keep track of what is out there, if for no other reason than to protect
the planet. NASA's current count of
near-Earth objects: just short of 10,000; and that figure is thought to
represent less than ten percent of the objects out there. No one has ruled out an eventual serious Earth
impact, although the probability is said to be extremely low.
What they do know with certainty: "This object's orbit is so well known
that there's no chance of a collision," Yeomans assures us. Its approach will alter its orbit around the sun in such a way as to keep it out of
Earth's neighborhood, at least in the foreseeable future. (I personally find
these “at least in the foreseeable future” assurances less than confidence building.)
"Space rocks hit the Earth's
atmosphere on a daily basis. Basketball-size objects come in daily.
Volkswagen-size objects come in every couple of weeks," Yeomans said. The grand total of space stuff hitting the
atmosphere every day? "About 100
tons," according to Yeomans, though most of it arrives harmlessly as
sand-sized particles.
NASA has been on a mission to find and
track all near-Earth objects that are .62 miles in diameter or larger. The effort is intended to give scientists and
engineers as much time as possible to learn if an asteroid or comet is on a
collision course with Earth, in hopes sending up a spacecraft or taking other
measures to avert catastrophe. An object
the size of DA14 can be expected to strike Earth about every 1,200 years.
DA14 will soar through the sky at about
eight miles per second. At that speed, if
it did hit the Earth, the energy equivalent of 2.4 million megatons of TNT would
be released and wipe out 750 square miles. In Siberia in 1908, forest land around the
Tunguska River was flattened by a slightly smaller asteroid that exploded five
miles above ground. The explosion killed
reindeer and flattened trees, leveling eighty million trees over 830 square
miles. The Tunguska event has been estimated
at 3 to 20 megatons...2012 DA14 is in the same approximate realm.
And let us not forget: approximately 66
million years ago, a six-mile diameter object smashed into what is now the
Yucatan Peninsula in Mexico leading to the demise of the dinosaurs as well as
most plant and animal life on Earth.
To all of this, to NASA and all the other planetary research agencies, I only ask the same question posed by Bruce
Willis in Armageddon:
“What’s your contingency plan?”
Until next time, LLAP!
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