With the celestial goings-on this year — the close fly-by of a large asteroid, one comet that's come and gone, another on its way, and a 55-foot asteroid that injured 1,500 people when it exploded over Russia — it's not surprising that people have gotten a bit concerned about what might be "out yonder" and on a collision course with our planet.
The fact is, nobody really knows. And while the advice given Tuesday by Charles Bolden, who heads NASA, may have been unusual for a man of science, it may be the best there is to offer right now.
Appearing before the Science Committee of the U.S. House, Bolden was asked what America could do about sizable celestial objects that could wreak havoc should they crash into the Earth.
"From the information we have, we don’t know of an asteroid that will threaten the population of the United States," Bolden said. "But if it’s coming in three weeks, pray."
The amount of energy that is packed into asteroids hurtling through space at thousands of miles per hour is amazing, as evidenced by the explosion in mid-February over Chelyabinsk, Russia. Captured on video with almost surreal images because of their similarity to cinematic science fiction productions, that asteroid generated an explosion that sent out a shockwave that damaged windows and buildings. Scientists believe it is the biggest event of its type since 1908.
Had it actually struck ground in a densely populated city, the death toll would have been high. At an estimated diameter of 55 feet, the asteroid falls into the class known as "city killers."
What was more sobering was a bigger asteroid that followed it in a fly-by that, while there was no chance it would strike Earth, came closer to our planet than the satellites that orbit above us to beam down weather information and television/radio entertainment signals.
Of the objects that could devastate the planet — diameters of more than six-tenths of a mile — NASA officials believe they know where the great majority (95 percent) are, and they're tracking them. But they think the 1,000 or so "city killers" they're tracking only comprise about 10 percent of what probably is out there.
As NASA officials say, the odds of destruction from the sky are slim. "City killers" can be expected to hit once a millennium, and the last "planet killer" asteroid was a 6-mile-wide one that hit the Yucatan Peninsula 66 million years ago, wiping out the dinosaurs and most of the plant life on Earth. But though the odds are heavily in our favor, the pure destruction from such a collision requires that officials take it seriously and work on technology that might someday divert an asteroid — and devastation.
In the meantime, all we can do is look for more of these space objects to catalog and track, as students at Lee County High School are doing under the instruction of physics and astronomy teacher Dave Baltenberger. His class of seniors is part of the International Astronomical Search Collaboration that has more than 5,000 high school and college students from 500-plus schools in 60 nations searching through data to locate asteroids that have so far gone undetected. The program has located 500 already, including 29 that have been numbered or named by the students who discovered them.
All in all, the questions about destruction from above are a reminder that as big as the Earth seems and as powerful as we think we are with the tools and energies we have harnessed, our planet is small and fragile in the overall scheme of the universe. And from that perspective, Bolden's advice doesn't seem out of line at all.