- In the past six months, while the world focused on the
continuing threat of global terrorism, as many as a dozen or more asteroids
sneaked up on the Earth and zoomed by at distances just beyond the Moon's
orbit and closer. Most were never noticed. Earlier this month, astronomers
did spot one. Four days after it flew by.
-
- In discussing these events, experts describe a planet
vulnerable to an unexpected attack that could, in an instant, wipe out
a city or even destroy civilization. Some researchers go so far as to view
the asteroid threat as an "international emergency situation,"
as Andy Smith of the Safety Research Institute in Albuquerque New Mexico
said last week.
-
- Yet as billions upon billions of dollars are spent to
provide insurance against terrorism, astronomers were foiled in a recent
attempt to encourage Australia to invest a comparatively paltry $1 million
to scan the mostly unsurveyed southern skies for killer space rocks.
-
- The scientists were practically laughed at on television
by the science minister of Australia who, like much of the world's public,
simply does not take the threat of asteroids seriously.
-
- The reason is simple: The Dread Factor is not high
enough.
-
- Paul Slovic, author of "The Perception of Risk"
(Earthscan, 2000), says most people are far more worried over what humans
and technology can do to them than they are about natural disasters. While
terrorism, chemical spills and nuclear accidents are awarded high
"Dread
Factor" marks by most people, asteroids, earthquakes and hurricanes
rate low.
-
- Stealth approach
-
- On March 8, a hunk of stone and metal about the size
of an 18-story building, made its closest approach to Earth, passing
roughly
298,400 miles (480,200 kilometers) from the planet, just a bit farther
out than the Moon, but a little too close for comfort for most
astronomers.
-
- But what was most disturbing was that the asteroid, later
named 2002 EM7, passed virtually unseen. Not until March 12, when it had
moved out of the glare of the Sun and into the night sky was it seen from
Earth.
-
- And it was not alone: On Jan. 7, an asteroid the size
of three football fields came within two lunar distances and was spotted
only a month before. Last October, a smaller asteroid passed by at a
similar
distance and was detected just two days prior.
-
- For each nearby asteroid that is spotted, several pass
entirely unnoticed, some closer to us than the Moon, scientists say. One
researcher estimates that each year, 25 asteroids roughly as large as 2002
EM7 whiz by at even closer distances.
-
- They slip through because of limitations to technology,
telescope time, and funding.
-
- These close brushes illustrate a message that asteroid
researchers have repeatedly tried to hammer home to politicians and the
public: The number of undiscovered asteroids far exceeds the known list,
and the list needs to be filled out before it's too late.
-
- Asteroid 2002 EM7 left a a pretty ominous message on
its own: Only a tremendously expensive new telescopes -- placed outside
Earth's orbit so as to monitor the blind spot created by the Sun -- could
guarantee we won't suffer an unexpected and sudden impact. There would
be a flash of brilliant light in the sky, and seconds later the world would
change forever in a way that would render Sept. 11 an insignificant
memory.
-
- Dread Factor vs. reality of risk
-
- Scientists develop asteroid risk statistics by estimating
the total number of objects that exist and by studying evidence of past
encounters -- big holes in the ground called impact craters.
-
- From these clues, they say your chances of death by
asteroid
are about the same as dying in a plane crash, roughly 1-in-20,000 during
your lifetime. You're more liable to be electrocuted to death (1-in-5000
chance), succumb to skin cancer or be killed in a car crash.
-
- Yet asteroids pose more risk than tornadoes (1-in-60,000
chance), rattlesnake bites or food poisoning.
-
- If Earth is hit, you could die by direct impact and
vaporization.
Or you might be killed in an associated earthquake or volcanic eruption
as the planet's bell is rung like never before in recorded history. Or
perhaps like countless lesser species, you'll die a slow, agonizing death
of starvation as the world's food supply dwindles in the face of reduced
sunlight caused by a global debris cloud.
-
- Yet if you're like most people, you are not all that
worried, according to sociologists and psychiatrists who study these
things.
-
- Slovic, the author, also works at Decision Research,
an organization in Oregon that advises industry and government about risk.
He says we do not base our fears on statistics. Instead, each of us
develops
our own personal Dread Factor for various frightening scenarios based on
personal experience, knowledge and, more important, our sense of the
situation.
-
- Emotion has replaced instinct as a major risk-assessment
tool for modern humans, who face myriad dangers, none of which involve
sneaking up on woolly mammoths from behind a tree.
-
- "It is more of a gut feeling," Slovic says.
"Does it worry me? Does it scare me? Does it make me
uneasy?"
-
- Cars are low on most individuals' Dread Factor lists,
even though the average American stands about a 1-in-100 or 1-in-200 chance
of dying in an automobile.
-
- "We don't dread cars," Slovic says.
"Things
that cause cancer are high on the Dread Factor."
-
- Scientists vs. voters
-
- The Dread Factor, or lack of it, can drive political
funding decisions.
-
- The U.S. Congress apparently perceived the threat real
enough to require NASA to make asteroid hunting a serious business. The
space agency spends $3.55 million each year searching for and studying
asteroids. (Much of that money goes to space-based research of asteroids
that pose no threat.)
-
- Individual search programs provide much of their own
institutional funding. And amateur astronomers around the globe contribute
to the effort. Not everyone, however, sees an urgent need.
-
- The Australian Science Minister Peter McGauran, appearing
on his country's 60 Minutes television program March 17, called the effort
to find potentially threatening asteroids "fruitless, unnecessary,
self-indulgent" and promised no funds unless researchers provide a
more convincing argument for the need.
-
- To the consternation of many researchers, there are no
telescopes below the equator devoted to searching southern skies for
asteroids.
Australia cut funding to one such effort in 1996.
-
- An ongoing online poll taken in conjunction with the
televised program found overwhelming support -- 91 percent at last count
-- for reinstatement of the funding. But these votes were cast by people
who watched an animated asteroid slam into Earth and listened to leading
experts spout frightening statistics and detail the grim outcomes they
say are only a matter of time.
-
- You and most other voters, in Australia and around the
world, probably lean more toward McGauran's sentiment. According to experts
in risk assessment and fear management, McGauran's starkest statement
likely
reflects the general public mood: "I lie awake worrying about a lot
of other things. Near-miss asteroids is not one of them."
-
- The average person tends to be much more afraid of
industrial
accidents, for example.
-
- As with terrorism, vast sums of money are spent, as
Slovic
puts it, "to take small risks of chemical and radioactive pollution
and reduce them even further. We spend a huge amount for every statistical
life saved. On the other hand, if you wanted to get people to spend money
on asteroid protection or earthquake mitigation, it's very difficult, even
though the risk is much greater."
-
- Richard Taylor of the Probability Research Group, a
global
affiliation of researchers looking into various science topics, thinks
there is a clear message in the fact that nations spend billions on
military
defense but zero scanning our entire Southern Hemisphere flank for
asteroids:
-
- "We feel more at danger from man than from
Nature,"
Taylor says.
-
- Next Page: Why we don't care
-
- Not in my lifetime
-
- A decade ago, Slovic and some colleagues conducted a
test. They provided a group of university students with information about
the threat from beyond, explaining that a giant asteroid was thought to
have killed off the dinosaurs, and others would surely hit the planet at
statistically determined intervals. Then they surveyed the students to
determine how they assessed the risk. The students recognized the threat,
but chose not to worry about it.
-
- "They're expectation was, well, it's not going to
happen in my lifetime," Slovic says.
-
- If astronomers were to announce an imminent collision,
asteroids would suddenly develop a high Dread Factor, Slovic figures. But
because none of us has any direct experience whatsoever with deadly space
rocks, "People don't get worked up about it. There's too many things
to worry about."
-
- Scientists find it similarly difficult to generate much
public worry for other potential calamities, like horrible storms, droughts
and coastal flooding that might result over the next century due to climate
change, but which are seen as remote in time.
-
- There is little chance that the complacent attitude of
the public, and of some government officials, will ever elevate to the
level of concern maintained by asteroid experts. As Slovic says, it's
common
for scientists and technicians to have a different and more rational
understanding
of the risks involved in their area of study.
-
- Fear as a motivator
-
- Many astronomers, it must be noted, believe present
asteroid
search efforts are fairly adequate, notwithstanding the lack of a southern
telescope. With time, they say, the worst threats will be rooted out, which
is to say the largest asteroids. And, they argue, the odds are that if
any globally destructive object is found to be on a collision course with
Earth, there will probably be years of warning.
-
- A more vocal group of astronomers and other proponents
of increased spending tend to worry about smaller asteroids that could
cause regional devastation. And they tend to make more frightening
statements.
Here are just a few that have come from the mouths of respected experts
just in the past 10 days:
-
- "If it were over a populated area, like Atlanta,
it would have basically flattened it," asteroid cataloguer Gareth
Williams told CNN in discussing the potential of asteroid 2002 EM7.
-
- "We live in a cosmic shooting gallery," said
Duncan Steel of Salford University.
-
- "We're talking about a million megaton
explosion,"
said author and physicist Paul Davies of Macquarie University, in
discussing
a typical impact on another recent television program. "That's a
million
city-bursting bombs all going off at once."
-
- While such statements are often softened with the
reminder
that the world probably won't end tonight -- Davies said in the next
breath,
"I don't want people to lie awake at night worrying about it"
-- the effort is clear: Get you and the politicians to act on this
threat.
-
- Yet in a world remade by a single day of terrorism, fear
may be doomed as a sales pitch, just as it was in Australia.
-
- Fear is not something that can necessarily be instilled
by scientists. Instead, it tends to be generated by whatever rears its
ugly head and shouts loudest, explains Robert Butterworth, a psychologist
at International Trauma Associates in Los Angeles. Nothing right now,
globally
speaking, can measure up to the fear of terrorism and the associated
potential
of a nuclear attack.
-
- I can't take it
-
- While there are plenty of things for a 21st Century human
to worry about, we all have our limits.
-
- "In order for us not to have these things on our
minds, we use a device that's been maligned in last few years, which is
denial and repression," Butterworth says. "We push it back,
because
we couldn't function if we didn't."
-
- Asteroids, like a fear of bugs or concern over a missed
appointment, can be lost in a shuffle of frightening thoughts. Some things
just aren't as significant as they seemed last summer.
-
- Butterworth puts it this way: "If we had been
walking
with a limp and all of a sudden were shot in the stomach, the limp fades
away."
-
- No place has been hit in the stomach like New York City.
Psychologist Janice Yamins, whose patients include victims of the terrorist
attacks, says residents are stunned by their own change in views, such
as newfound support for defense spending "instead of other things
that won't help preserve our world."
-
- Where fear leaves off, anger and revenge step in.
-
- Natural disasters don't generate similar sea changes
in philosophy. Californians suffer tremendously from earthquakes every
few years. They pick up and move on. Southeast coastal residents rebuild
time and again after hurricanes. People there shrug off the threat.
Butterworth
figures an asteroid impact would generate similar reactions.
-
- "What do we do, shake our fist at God?" he
asks. "Who can we be angry at?"
-
- All this psychology lends support to a notion that has
already formed in the heads of many astronomers: Their call for more
funding
will fall on a whole lot of deaf ears until another asteroid makes real
noise.
-
- The last serious impact was in 1908, when a rock about
the same size as 2002 EM7 exploded above the surface of Siberia. Roughly
1,200 square miles (3,108 square kilometers) of forest were flattened in
a remote region known as Tunguska. There were no known deaths, because
almost no one lived there.
-
- The odds of a similar event, which could easily destroy
a large city or a small state with miles of extra destruction to boot,
are about 1-in-20 over the next 50 years.
-
- Knowledge and false alarms
-
- In the past decade, about 500 very large space rocks
have been found to wander near the space shared by Earth's orbit. These
so-called Near Earth Asteroids, all larger than 1 kilometer (0.6 miles),
represent about half the expected total. Millions of smaller asteroids
are almost entirely uncatalogued.
-
- The larger rocks are the ones many scientists fear most.
If one hit Earth, civilization would be pushed to the brink and perhaps
beyond. Deaths could easily be counted in millions, possibly even billions.
Many species of plants and animals would disappear.
-
- As more asteroids are discovered and publicized, public
awareness of the threat grows. But the information is not always
accurate.
-
- In a couple of high-profile cases, most prominently four
years ago with an asteroid called 1997 XF11, the public was warned of
potentially
devastating impacts before further calculations showed the newly found
rocks to be no threat at all.
-
- Worse, late-night radio programs and various web sites
spout all sorts of unscientific claims of impending asteroid doom, reports
that spread like tsunami radiating outward from an ocean impact. Any
reporter
who covers the subject has gotten more than a few frantic e-mails from
concerned citizens who heard this or that and were worried about the
planet-destroyer
coming next June, or whenever.
-
- Movies like Armageddon only enhance "wild
inaccuracies"
in some minds, says Taylor of the Probability Research Group.
-
- All of this -- the fact, the fiction, the unfounded fears
and the genuine threats that some people don't fear at all -- create a
gulf of apathy and misunderstanding that may well prevent asteroid experts
from convincing you to see the world as they see it.
-
- Several dozen professional astronomers, meanwhile,
maintain
a nightly vigil in the Northern Hemisphere, scanning immense and dark skies
for tiny points of light, then struggling to observe often minor movements
against the background of stars in order to determine a trajectory, an
ultimate destination.
-
- Always on their minds: Will this one hit
Earth?
-
- "It isn't a matter of if one of these things is
going to hit the Earth," said Duncan Steel on the 60 Minutes
broadcast.
"It's just a matter of when. Either we can expect 23 years warning
or six or seven seconds."
-
- For those in the know, the asteroid Dread Factor is off
the charts.
-
- Copyright © 2002 SPACE.com
|
