Skip to main content

Don't count 'doomsday asteroid' out yet

By Greg Bear, Special to CNN
January 24, 2013 -- Updated 1346 GMT (2146 HKT)
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
October 1, 2014 -- Updated 1947 GMT (0347 HKT)
Julian Zelizer says Jimmy Carter's message about the need to restore trust in public officials is a vital one, decades after the now 90-year-old he first voiced it
October 1, 2014 -- Updated 2156 GMT (0556 HKT)
Ford Vox says mistakes and missed opportunities along the line to a diagnosis of Ebola in a Liberian man have put Dallas residents at risk of fatal infection
October 1, 2014 -- Updated 2221 GMT (0621 HKT)
Pepper Schwartz says California is trying, but its law requiring step-by-step consent is just not the way hot and heavy sex proceeds on college campuses
October 2, 2014 -- Updated 0217 GMT (1017 HKT)
Mike Downey says long-suffering fans, waiting for good playoff news since 1985, finally get something to cheer about
October 1, 2014 -- Updated 2139 GMT (0539 HKT)
Steve Israel saysJohn Boehner's Congress and the tea party will be remembered for shutting down government one year ago
October 1, 2014 -- Updated 1856 GMT (0256 HKT)
Yep. You read the headline right, says Peter Bergen, writing on the new government that stresses national unity
October 1, 2014 -- Updated 2312 GMT (0712 HKT)
Hong Kong's pro-democracy demonstrators are but the latest freedom group to be abandoned by the Obama administration, says Mike Gonzalez
September 30, 2014 -- Updated 1653 GMT (0053 HKT)
Jeff Yang calls Ello a wakeup call to Facebook and Twitter, and a sign of hope for fast-rising upstarts Pinterest and Snapchat.
October 1, 2014 -- Updated 1423 GMT (2223 HKT)
Paul Waldman says the Secret Service should examine its procedures to make sure there are no threats to the White House--but without losing the openness so valuable to democracy
October 1, 2014 -- Updated 1455 GMT (2255 HKT)
Jesse Williams says the videotape and 911 call that resulted in police gunning down John Crawford at a Walmart reveals the fatal injustice of racial assumptions
September 30, 2014 -- Updated 2303 GMT (0703 HKT)
Mel Robbins says officials should drop the P.C. pose: The beheading in Oklahoma was not workplace violence. Plenty of evidence shows Alton Nolen was an admirer of ISIS.
September 30, 2014 -- Updated 1911 GMT (0311 HKT)
The Occupy Central movement has already achieved much by bringing greater attention to Hong Kong's struggle for democracy, William Piekos says..
September 30, 2014 -- Updated 1911 GMT (0311 HKT)
The Occupy Central movement has already achieved much by bringing greater attention to Hong Kong's struggle for democracy, writes William Piekos.
September 30, 2014 -- Updated 1413 GMT (2213 HKT)
As Prime Minister Narendra Modi visits America, Madeleine Albright says a world roiled by conflict needs these two great democracies to commit to moving their partnership forward
September 30, 2014 -- Updated 1404 GMT (2204 HKT)
John Sutter: Lake Providence, Louisiana, is the parish seat of the "most unequal place in America." And until somewhat recently, the poor side of town was invisible on Google Street View.
September 29, 2014 -- Updated 1311 GMT (2111 HKT)
Julian Zelizer says in the run up to the 2016 election the party faces divisions on its approach to the U.S.'s place in the world
September 29, 2014 -- Updated 1419 GMT (2219 HKT)
Ruben Navarrette says Common Core supporters can't devise a new set of standards and then fail to effectively sell it.
September 30, 2014 -- Updated 1329 GMT (2129 HKT)
Earlier this month, Kenyans commemorated the heinous attack on the Westgate Mall in Nairobi.
September 30, 2014 -- Updated 1859 GMT (0259 HKT)
David Wheeler says Colorado students are right to protest curriculum changes that downplays civil disobedience.
September 27, 2014 -- Updated 0158 GMT (0958 HKT)
Sally Kohn says when people click on hacked celebrity photos or ISIS videos, they are encouraging the bad guys.
September 26, 2014 -- Updated 1155 GMT (1955 HKT)
Loren Bunche says she walked by a homeless man every day and felt bad about it -- until one day she paused to get to know him
September 30, 2014 -- Updated 1332 GMT (2132 HKT)
ISIS grabs headlines on social media, but hateful speech is no match for moderate voices, says Nadia Oweidat.
September 29, 2014 -- Updated 1233 GMT (2033 HKT)
A new report counts jihadists fighting globally. The verdict? The threat isn't that big, says Peter Bergen.
September 23, 2014 -- Updated 2137 GMT (0537 HKT)
Ebola could become the biggest humanitarian disaster in a generation, writes former British Prime Minister Tony Blair
September 26, 2014 -- Updated 1658 GMT (0058 HKT)
ISIS has shocked the world. But will releasing videos of executions backfire? Four experts give their take.
September 26, 2014 -- Updated 1439 GMT (2239 HKT)
Eric Holder kicked off his stormy tenure as attorney general with a challenge to the public that set tone for six turbulent years as top law-enforcement officer.
September 26, 2014 -- Updated 1309 GMT (2109 HKT)
LZ Granderson says Obama was elected as a war-ending change agent, not a leader who would leave behind for his successor new engagement in Iraq and Syria. Is he as disappointed as the rest of us?
September 24, 2014 -- Updated 0910 GMT (1710 HKT)
Gayle Lemmon says the question now is how to translate all the high-profile feminizing into real gains for women
ADVERTISEMENT