Provisional
Truth | Essays | April 13, 2007
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Day - Apophis the Destroyer
As
if we didn't have anything else to worry about, here comes
some dandy news from outer space. Asteroid 99942 Apophis, a
thousand-foot diameter chunk of rock discovered in 2004,
will rendezvous with Earth again on April 13, 2029 (a
Friday, of course), hopefully slipping by us at a near-miss
distance of about 18,000 miles.
That's closer than many satellites and well-within the
Moon's orbit, and Apophis, the Greek name for an Egyptian
god of darkness and chaos – naturally – will be visible to
the naked eye in parts of Europe North Africa and western
Asia as it whizzes by. Talk about close encounters of the
worst kind, but wait, it gets better.
In
2004, when discovered, Apophis and Earth came within cosmic
waving distance at 9 million miles. In 2029, it will sweep
above us by less than 20,000 miles, close enough to our
planet for its gravity to possibly alter Apophis's
trajectory for a really close encounter a few years
later.
Early on scientists estimated a 1-in-10,000 chance Apophis
could hit Earth on Sunday, April 13, 2036. And you
thought we only had to worry about global warming,
overpopulation, peak oil, nuclear war, religious
intolerance, AIDS, terrorist attacks, avian flu,
earthquakes, tsunamis, supervolcanoes, rising sea levels,
death and taxes.
David Morrison,
a space scientist and asteroid specialist at NASA’s Ames
Research Center, situated in Silicon Valley, California,
says the possibility of Apophis hitting Earth on April 13,
2036 is real, even if the once-slight probability now seems
to be even smaller (a 1-in-45,000 chance as of the
most recent
calculation in October 2006).
“These
probabilities represent uncertainties in our knowledge of
the orbit, not a failure of the science,” Morrison said. But
whether the asteroid will strike Earth or not, Morrison
concluded, the challenge is to resolve which case is
correct. “With more observations over a longer time span, we
will be able to tie this down.”
The
last major near-Earth-object (NEO) to strike the planet was
near the Tunguska region of Siberia in 1908, an estimated
200-foot-diameter object which likely exploded above ground,
producing a shock wave that rearranged more than 800 square
miles of remote landscape and kicking up dust that altered
evening sunsets for several days.
The
Tunguska blast event corresponded to an estimated at 10-20
megatons of TNT, equivalent to the most powerful nuclear
bomb detonated by the United States. By comparison, the
atomic bomb detonated over Hiroshima on August 6, 1945
produced an explosion of roughly 13 kilotons of TNT, at
least a thousand times less destructive than Tunguska.
Apophis, however, could generate 1,000 – 1,200 megatons of
destructive energy, five or six times that of the volcanic
eruption of Krakatoa in 1883.
That
explosive eruption ejected into the atmosphere more than 25
cubic kilometers of rock, dust and ash and its sound was
heard more than 3,000 miles away. As ash and dust
circumnavigated the globe, average temperatures declined in
many areas for several years and it created optical
atmospheric effects such as spectacular, deeply colorful
sunsets and “blue” moons.
(Some suggest the blood-red sky shown in Edvard Munch's
famous 1893 painting “The Scream” is an accurate depiction
of the sky over Norway after the eruption. Munch said:
"suddenly the sky turned blood red ... I stood there shaking
with fear and felt an endless scream passing through
nature.")
An
Apophis-sized asteroid impact would be exponentially more
devastating than Krakatoa, not only because of the
possibility of a dry-land impact in a populated area, but
more so due to the massive quantities of dust and dirt which
would be lifted into the atmosphere and the resultant
“nuclear winter” as the clouds blocked sunlight for months.
An ocean impact would create massive tsunamis with
destructive forces unlike anything mankind can imagine.
(To
more fully imagine the consequences of nuclear winter, read
Cormac McCarthy's 2006 novel The Road, which offers a
chilling glimpse of post-apocalyptic life on Earth for the
survivors of an undefined catastrophe.)
We'll get a couple more shots at refining our calculations.
Apophis and Earth get together again observationally in 2013
and 2021, which scientists hope will give them enough data
to conclude with even more accuracy than the current 99.9978
percent likelihood a 2036 impact scenario can be ruled out.
That 0.0022 percent chance – one in 45,000 – of collision
cannot be eliminated until after the gravitational effects
of the 2029 close encounter are more reliably defined.
Perhaps more fittingly than can be comprehended by human
minds, April 13, 2036 will be Easter Sunday, the day
hundreds of millions of Christians celebrate the believed
resurrection of Jesus of Nazareth that is the basis of their
faith.
Christians expectantly have been waiting through the ages
for Jesus to return, the “second coming” prophesied to usher
in a thousand-year kingdom of God on Earth. If Jesus arrives
with Apophis in fewer than 30 years, he may find little left
over which to reign.
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