PASADENA, Calif.

ON Feb. 15, an asteroid designated 2012 DA14 will pass safely within about 17,200 miles of Earth’s surface — closer than the communication satellites that will be broadcasting the news of its arrival. The asteroid is about 150 feet in diameter and has a mass estimated at about 143,000 tons.

Should an object of that size hit Earth, it would cause a blast with the energy equivalent of about 2.4 million tons — or 2.4 megatons — of TNT explosives, more than 180 times the power of the atomic blast that leveled Hiroshima.

It’s almost as if nature is firing a shot across our bow to direct our attention to the vast number of nearby rocky asteroids and a few icy comets that make up what we call the near-Earth object population. We should take the warning seriously.

While no known asteroids or comets represent a worrisome impact threat now, NASA’s Jet Propulsion Laboratory shows more than two dozen asteroids have better than a one in a million chance of smacking into Earth within the next 100 years. That may sound reassuring, but we estimate that less than 10 percent of all near-Earth objects have been discovered. And while we are keeping a vigilant eye out for these objects in the Northern Hemisphere, we are considerably less watchful in the Southern Hemisphere.