SPACE
Asteroids and Comets: Deadly
Dangers from Above
By Gailon Totheroh
CBN News Science and Medical Reporter
Comets generally travel
faster than asteroids, as fast as 150,000 miles an hour, meaning they could
pack a bigger punch.
CBN.com
(CBN News) - Scientists are concerned about terrorism like many
of us are today, but not from people -- from outer space.
Asteroids and comets constantly spin near us, threatening death and destruction.
A dead-on hit by the largest of these cosmic cannonballs could mean the end
of life as we know it.
Now is the time for a new age of exploration and discovery, to go seek out the
universe -- but maybe it's the reverse -- the universe may be coming after us,
in the form of comets or asteroids.
Physics and astronomy professors like Gary Copeland at Old Dominion University
are predicting 'an event' could be right around the corner. "We'll get
one to two events per century that will be equal to all the destructive power
of all the weapons in World War II."
That would mean that the event would be equivalent to the total destructive
power of every bullet, every shell, every mortar, every bomb of WW II hitting
at once -- including the atomic ones.
The last space projectile of this magnitude was a mere 200 feet across. The
asteroid struck central Russia in 1908, and the resulting fireball torched
miles and miles of forest. But fortunately, the area was nearly uninhabited.
Copeland remarked, "If it [the central Russian asteroid] had happened
over New York City, it would have been a different ball game."
CBN News asked him, "Meaning millions killed?" Copeland replied,
"Yes, yes."
Hollywood envisioned this scenario with the movie, "Deep Impact."
In the movie, it is discovered that two comets are on a collision course with
Earth.
But while Hollywood may sensationalize the risk, members of Congress are
seriously concerned. Representative Dana Rohrbacher, who leads the House Space
and Aeronautics Subcommittee, said, "There is a threat to us and to our
lives, of objects coming from space that could hit our planet and kill millions
of people. It's happened in the past and it will happen in the future. The
question is when, and how many people will be affected. "
Not so long ago, science assumed the risk was even smaller for these extremely
rare events. But better technology means we're discovering more, and finding
a higher risk than was first believed.
Any actual strike brings some devastation, and with the planet's surface
two-thirds water, well, that's a big target.
Copeland said, "There's probably evidence that several things like this
happened in previous centuries, but they didn't land on Earth. On water is
where they hit, and of course, they produced the Tsunamis, the tidal waves."
Copeland says the impact of a space object can generate 900-foot waves, similar
to the impact envisioned in Hollywood films. And if there is little advance
warning, low-lying areas near the strike are more than vulnerable. "It's
not survivable, nor is it escapable," says Copeland. "You get in
your car and try to drive away, meanwhile a wave moving at 600 miles an hour
comes in. There's no way."
And how about a sizable mass that hit in the Atlantic? Copeland said that
places like Florida, which is pretty flat, "would be inundated, it would
disappear for a while."
And a medium-sized strike off the California coast? Also deadly.
But even that much devastation doesn't compare with the mother of all asteroid
strikes in the past.
"There's a place in Africa that's a crater over a hundred miles across,"
Copeland explains. "It wasn't recognized as a crater until they had satellite
photographs to see it." The Vredefort crater has a diameter of 185 miles,
and was created by an asteroid estimated to be six miles wide.
The damage today from even a much smaller rock could mean long-term global
devastation.
An asteroid or comet impact on land would shoot debris high into the atmosphere,
and could create year-round winter conditions by blocking sunlight for a year
or more. That would lead to unstable weather patterns with a nearly non-existent
growing season. And that could mean mass starvation and economic ruin for
years.
Part of the reason asteroids and comets can pack so much damage is their
velocity. Comets generally travel faster than asteroids, as fast as 150,000
miles an hour, meaning they could pack a bigger punch. Don't get too comfortable,
though, the slowest asteroids travel at a deadly 25,000 miles an hour.
And don't forget that the pull of the planets can alter the course of asteroids,
and especially comets, when Jupiter drags them closer to Earth.
So are we all just doomed if one of these astral assailants strikes right
off our shores? Is there anything we can do to stop an asteroid from smashing
into our neighborhoods? The truth of the matter is, right now, not much.
But astronomers are getting better at tracking them. Still, with most observatories
in the Northern Hemisphere, objects flying in the Southern skies could more
easily go undetected. So far, astronomers have discovered 700 or so, out of
an estimated 1100 of the largest, most dangerous asteroids.
And each sighting does boost our potential to protect ourselves. There is
even a global effort to look for asteroids. That is the Spaceguard Survey,
and Congressman Rohrbacher wants to go further, with the Pete Conrad bill.
"The purpose of the Pete Conrad bill," says Rohrbacher, "is
to get people looking up, and not just looking down. Certainly we have to
worry that we might stumble over things in our path, but we also have to worry
about what might be coming at us from up above."
And already on the drawing boards are plans to launch a rocket with a bomb,
to divert an asteroid headed our way. That could make the rock speed harmlessly
past us. Better science will give us more lead-time on a threat, enabling
the kind of evacuations already used for flooding and storms, perhaps even
with months or years of advance notice.
University scientists are already working on the problem of an asteroid or
comet collision, but they really need more research to accurately assess the
danger. With funding, that could take about 10 years, and by then government
officials could come up with a plan to at least minimize the potential global
impact.
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