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 10:53 AM EDT, Thu April 17, 2014
Michael Bloomberg and Shannon Watts say Americans are ready for sensible gun laws, but politicians are cowed by the NRA. Everytown for Gun Safety will prove the NRA is not that powerful.
updated 9:28 AM EDT, Thu April 17, 2014
Ruben Navarrette says Steve Israel is right: Some Republicans encourage anti-Latino prejudice. But that kind of bias is not limited to the GOP.
updated 7:23 PM EDT, Wed April 16, 2014
Peggy Drexler counts the ways Phyllis Schlafly's argument that lower pay for women helps them nab a husband is ridiculous.
updated 12:42 PM EDT, Wed April 16, 2014
Rick McGahey says Rep. Paul Ryan is signaling his presidential ambitions by appealing to hard core Republican values
updated 11:39 AM EDT, Wed April 16, 2014
Paul Saffo says current Google Glasses are doomed to become eBay collectibles, but they are only the leading edge of a surge in wearable tech that will change our lives
updated 2:49 PM EDT, Tue April 15, 2014
Kathleen Blee says the KKK and white power or neo-Nazi groups give haters the purpose and urgency to use violence.
updated 7:56 AM EDT, Wed April 16, 2014
Sen. Sheldon Whitehouse and Rep. Henry Waxman say read deep, and you'll see the federal Keystone pipeline report spells out the pipeline is bad news
updated 7:53 AM EDT, Wed April 16, 2014
Frida Ghitis says President Obama needs to stop making empty threats against Russia and consider other options
updated 5:29 PM EDT, Tue April 15, 2014
Peter Bergen and David Sterman say the Kansas Jewish Center killings are part of a string of lethal violence in the U.S. that outstrips al Qaeda-influenced attacks. Why don't we pay more attention?
updated 12:41 PM EDT, Tue April 15, 2014
Danny Cevallos says families of the passengers on Malaysian Airlines Flight 370 need legal counsel
updated 11:23 AM EDT, Mon April 14, 2014
David Frum says Russia is on a rampage of mischief while Western leaders and Western alliances charged with keeping the peace hem and haw
updated 7:56 AM EDT, Mon April 14, 2014
Most adults make the mistakes of hitting the snooze button and of checking emails first thing in the morning, writes Mel Robbins
updated 1:54 PM EDT, Mon April 14, 2014
David Wheeler says as middle-class careers continue to disappear, we need a monthly cash payment to everyone
updated 7:55 AM EDT, Mon April 14, 2014
Democrats need to show more political spine when it comes to the issue of taxes.
updated 11:55 AM EDT, Mon April 14, 2014
Donna Brazile recalls the 50th Anniversary of the Civil Rights Act as four presidents honored the heroes of the movement and Lyndon Johnson, who signed the law
updated 9:17 AM EDT, Mon April 14, 2014
Elmer Smith remembers Chuck Stone, the legendary journalist from Philadelphia who was known as a thorn in the side of police and an advocate for the little guy
updated 2:56 PM EDT, Sun April 13, 2014
Al Franken says Comcast, the nation's largest cable provider, wants to acquire Time Warner Cable, the nation's second-largest cable provider. Should we be concerned?
updated 11:22 AM EDT, Fri April 11, 2014
Philip Cook and Kristin Goss says the Pennsylvania stabbing attack, which caused grave injury -- but not death, carries a lesson on guns for policymakers
updated 3:06 PM EDT, Fri April 11, 2014
Wikipedia lists 105 football movies, but all too many of them are forgettable, writes Mike Downey
updated 10:32 AM EDT, Fri April 11, 2014
John Sutter and hundreds of iReporters set out to run marathons after the bombings -- and learned a lot about the culture of running
updated 12:49 PM EDT, Fri April 11, 2014
Timothy Stanley says it was cowardly to withdraw the offer of an honorary degree to Ayaan Hirsi Ali. The university should have done its homework on her narrow views and not made the offer
updated 10:16 AM EDT, Fri April 11, 2014
Al Awlaki
Almost three years after his death in a 2011 CIA drone strike in Yemen, Anwar al-Awlaki continues to inspire violent jihadist extremists in the U.S, writes Peter Bergen
updated 9:21 PM EDT, Fri April 11, 2014
David Bianculli says Colbert is a smart, funny interviewer, but ditching his blowhard persona to take over the mainstream late-night role may cost him fans
updated 1:31 PM EDT, Thu April 10, 2014
Rep. Paul Ryan says the Republican budget places its trust in the people, not in Washington
updated 5:28 PM EDT, Thu April 10, 2014
Aaron David Miller says Obama isn't to blame for Kerry's lack of progress in resolving Mideast talks
updated 11:22 AM EDT, Mon April 14, 2014
David Weinberger says beyond focusing on the horrors of the attack a year ago, it's worth remembering the lessons it taught about strength, the dangers of idle speculation and Boston's solidarity
updated 12:32 PM EDT, Thu April 10, 2014
Katherine Newman says the motive for the school stabbing attack in Pennsylvania is not yet known, but research on such rampages turns up similarities in suspects and circumstances
updated 2:39 PM EDT, Wed April 9, 2014
Wendy Townsend says the Rattlesnake Roundup -- where thousands of pounds of snakes are killed and tormented -- is barbaric
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT