Skip to main content

Don't count 'doomsday asteroid' out yet

By Greg Bear, Special to CNN
updated 8:46 AM EST, Thu January 24, 2013
The March 1966 cover of Analog Science Fiction/Science Fact featured an illustration of an asteroid hitting Earth. J.E. Enever published his ground-breaking article,
The March 1966 cover of Analog Science Fiction/Science Fact featured an illustration of an asteroid hitting Earth. J.E. Enever published his ground-breaking article, "Giant Meteor Impact," in this issue, detailing what such strikes could do, and have done, to the Earth, with vivid prose and terrifying physics.
STORY HIGHLIGHTS
  • Greg Bear: Asteroid Apophis flew by this month and was much larger than expected
  • Named after an evil Egyptian serpent god, Apophis swings by every seven years
  • Bear: We can never be 100% sure how close it will come or if events might change its course
  • If Apophis hit Earth, he says, the blast would be the equivalent of over a billion tons of TNT

Editor's note: Greg Bear is an internationally bestselling science-fiction author of many books, including "Moving Mars," "Darwin's Radio" and "Hull Zero Three." As a freelance journalist, he covered 10 years of the Voyager missions at the Jet Propulsion Laboratory.

(CNN) -- Look up at our nearest neighbor, the moon, and you'll see stark evidence of the dangerous neighborhood we live in. The Man in the Moon was sculpted by large-scale events, including many meteor and asteroid impacts.

In 1994, the comet Shoemaker-Levy 9 dove into Jupiter. The result was awesome. The impact caused a brilliant flash, visible in Earth telescopes, and left an ugly dark scar on Jupiter's cold, gaseous surface.

Greg Bear
Greg Bear

With the recent fly-by of a 1,000-foot-wide asteroid labeled 99942 Apophis, one of a class of space rocks referred to as "near-Earth objects" or "Earth-grazers," scientists have revised their worst estimates of its chances of striking Earth. Current thinking is: We're safe. For the next couple of decades.

But this does not mean the danger is over. Far from it.

Become a fan of CNNOpinion
Stay up to date on the latest opinion, analysis and conversations through social media. Join us at Facebook/CNNOpinion and follow us @CNNOpinion on Twitter. We welcome your ideas and comments.



Named after the evil Egyptian serpent god Apophis, lord of chaos and darkness -- and recently dubbed the "doomsday asteroid" -- it flies past Earth every seven years. This year, its 1,000-foot bulk approached to within 9 million miles. In 2029, it will swoop in close enough to put some of our orbiting satellites in peril -- 20,000 miles. In that year, no doubt Apophis will arouse even more attention, because it will be visible in the daytime sky. In 2036, it will probably pass by at a reassuring 14 million miles.

Yet there's always a possibility we don't have these measurements exactly right. Something could happen at any point in Apophis' orbit to modify its course, just a smidgen. A tiny collision with another object, way out beyond Mars? What could change between now and 2029, or during any orbit thereafter?

Apophis masses at more than 20 million tons. If it hit Earth, the impact would unleash a blast the equivalent of over a billion tons of TNT. That's not an extinction event, but it could easily cause billions of deaths and months, if not years, of climate disruption.

The potential risk is huge. And Apophis is far from alone. Life in our solar system has always been dangerous. As kids we learn about the Barringer Crater in Arizona, a relatively recent formation -- 50,000 years old -- caused by a rock weighing several times more an aircraft carrier. That impact released the equivalent of 20 megatons of TNT and left a crater 4,000 feet wide.

Both Mars and Earth were long ago hit by planet-sized objects, one spinning off our Moon, the other shaping two distinctly different hemispheres on Mars. To this day, a steady rain of meteors falls on Earth -- some of them left-over pebbles and dust from worn-out comets, others from the "asteroid belt," still others from big strikes on the Moon and Mars.

Asteroid to fly between Earth, moon
Debunking doomsday: Killer asteroid
The Number: hazardous asteroids
The Number: hazardous asteroids

Since oceans cover two-thirds of the Earth's surface, it's more likely debris will hit water than land. Scientists believe it was the blast of a 6-mile-wide asteroid off the coast of Mexico some 64 million years ago that changed Earth's weather for years and hastened the departure of the dinosaurs. Ocean hits are worse than land hits, not just because of immense tidal waves, but because of the vast quantities of super-heated water vapor and dust that spread from the impact to shroud the entire Earth.

In March 1966, J.E. Enever published his ground-breaking article, "Giant Meteor Impact," in the periodical Analog Science Fiction/Science Fact. Enever surveyed the available material on meteor and asteroid strikes, then published his own calculations and analysis of what such strikes could do, and have done, to the Earth, with cinematically vivid prose and equally terrifying physics.

He was the first to put it all together and publish in a respected and widely available forum. Although geology was still reluctant to admit to any form of "catastrophism," eschewing biblical explanations, many read and pondered ... seriously.

In the decades since Enever's article, writers, scientists, and engineers have proposed various ways to avert such disasters. Some have suggested we strap rocket motors to a threatening rock and nudge it away. A steady pulse of projectile "paintballs" could also do the trick.

Others have suggested we use nuclear weapons to "kick" an asteroid from its orbit, or even to shatter it into smaller debris -- a rather dim idea that misleads us into believing a single bullet is worse than the blast from a shotgun. Our atmosphere provides little protection against meteors larger than a truck.

Moreover, many asteroids are chunky masses of rock and dust loosely held together by very little gravity, like loosely packed peanut clusters. Attempting to attach a rocket to one of these might merely dislodge a few "peanuts," leaving the rest to do the dirty work.

Wrap one of these peanut clusters in a giant steel net, then drag it off its deadly course? Intriguing, but for now -- like deploying tractor beams from the starship Enterprise -- it's just so much super-science.

Follow @CNNOpinion on Twitter.

Join us at Facebook/CNNOpinion.

The opinions expressed in this commentary are solely those of Greg Bear.

ADVERTISEMENT
Part of complete coverage on
updated 12:26 PM EDT, Wed August 27, 2014
The death of Douglas McAuthur McCain, the first American killed fighting for ISIS, highlights the pull of Syria's war for Western jihadists, writes Peter Bergen.
updated 6:42 PM EDT, Tue August 26, 2014
Former ambassador to Syria Robert Ford says the West should be helping moderates in the Syrian armed opposition end the al-Assad regime and form a government to focus on driving ISIS out
updated 9:21 AM EDT, Wed August 27, 2014
Ruben Navarrette says a great country does not deport thousands of vulnerable, unaccompanied minors who fled in fear for their lives
updated 9:19 AM EDT, Wed August 27, 2014
Robert McIntyre says Congress is the culprit for letting Burger King pay lower taxes after merging with Tim Hortons.
updated 7:35 PM EDT, Tue August 26, 2014
Wesley Clark says the U.S. can offer support to its Islamic friends in the region most threatened by ISIS, but it can't fight their war
updated 7:26 AM EDT, Wed August 27, 2014
Jeff Yang says the tech sector's diversity numbers are embarrassing and the big players need to do more.
updated 4:53 PM EDT, Tue August 26, 2014
America's painful struggle with racism has often brought great satisfaction to the country's rivals, critics, and foes. The killing of Michael Brown and its tumultuous aftermath has been a bonanza.
updated 4:19 PM EDT, Tue August 26, 2014
Ed Bark says in this Emmy year, broadcasters CBS, ABC and PBS can all say they matched or exceeded HBO. These days that's no small feat
updated 3:19 PM EDT, Tue August 26, 2014
Rick Martin says the death of Robin Williams brought back memories of his own battle facing down depression as a young man
updated 11:58 AM EDT, Tue August 26, 2014
David Perry asks: What's the best way for police officers to handle people with psychiatric disabilities?
updated 3:50 PM EDT, Mon August 25, 2014
Julian Zelizer says it's not crazy to think Mitt Romney would be able to end up at the top of the GOP ticket in 2016
updated 4:52 PM EDT, Mon August 25, 2014
Roxanne Jones and her girlfriends would cheer from the sidelines for the boys playing Little League. But they really wanted to play. Now Mo'ne Davis shows the world that girls really can throw.
updated 12:29 PM EDT, Mon August 25, 2014
Peter Bergen and Emily Schneider say a YouTube video apparently posted by ISIS seems to show that the group has a surveillance drone, highlighting a new reality: Terrorist groups have technology once only used by states
updated 5:04 PM EDT, Mon August 25, 2014
Kimberly Norwood is a black mom who lives in an affluent neighborhood not far from Ferguson, but she has the same fears for her children as people in that troubled town do
updated 5:45 PM EDT, Fri August 22, 2014
It apparently has worked for France, say Peter Bergen and Emily Schneider, but carries uncomfortable risks. When it comes to kidnappings, nations face grim options.
updated 1:27 PM EDT, Tue August 26, 2014
John Bare says the Ice Bucket Challenge signals a new kind of activism and peer-to-peer fund-raising.
updated 8:31 AM EDT, Fri August 22, 2014
James Dawes says calling ISIS evil over and over again could very well make it harder to stop them.
updated 9:05 PM EDT, Sat August 23, 2014
As the inquiry into the shooting of Michael Brown continues, critics question the prosecutor's impartiality.
updated 6:47 PM EDT, Fri August 22, 2014
Newt Gingrich says it's troubling that a vicious group like ISIS can recruit so many young men from Britain.
updated 10:50 AM EDT, Thu August 21, 2014
David Weinberger says Twitter and other social networks have been vested with a responsibility, and a trust, they did not ask for.
updated 7:03 AM EDT, Fri August 22, 2014
John Inazu says the slogan "We are Ferguson" is meant to express empathy and solidarity. It's not true: Not all of us live in those circumstances. But we all made them.
updated 8:23 AM EDT, Fri August 22, 2014
Retired Lt. Gen. Mark Hertling says he learned that the territory ISIS wants to control is amazingly complex.
updated 3:51 PM EDT, Wed August 20, 2014
Cerue Garlo says Liberia is desperate for help amid a Ebola outbreak that has touched every aspect of life.
updated 1:42 PM EDT, Thu August 21, 2014
Eric Liu says Republicans who want to restrict voting may win now, but the party will suffer in the long term.
updated 11:38 AM EDT, Thu August 21, 2014
Jay Parini: Jesus, Pope and now researchers agree: Wealth decreases our ability to sympathize with the poor.
updated 8:00 AM EDT, Thu August 21, 2014
Judy Melinek offers a medical examiner's perspective on what happens when police kill people like Michael Brown.
updated 6:03 PM EDT, Tue August 19, 2014
It used to be billy clubs, fire hoses and snarling German shepherds. Now it's armored personnel carriers and flash-bang grenades, writes Kara Dansky.
updated 1:27 PM EDT, Wed August 20, 2014
Maria Haberfeld: People who are unfamiliar with police work can reasonably ask, why was an unarmed man shot so many times, and why was deadly force used at all?
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT