Asteroid nearly two miles wide sails past Earth

Asteroid fly-by didn't pose a risk of striking Earth, but NASA is working to catalog space rocks that could pose a threat – and be ready to deflect them.

Whew, that was close.

A massive asteroid, nearly two miles wide, hurtled past Earth late Friday.

It was “near” by the standards of astrophysics – just 3.5 million miles away.

That’s actually more than 14 times further from Earth than the moon. So you probably didn’t feel any cosmic breeze when the asteroid named 1998 QE2 flew by at about 5 p.m. in America’s Eastern time zone.

But such rogue rocks warrant close watching, given the potential devastation that could occur if one were to strike Earth.

The need to safeguard the planet – against both large asteroids and potentially against smaller objects like the one that caused injuries this year near Chelyabinsk, Russia – was the subject of recent congressional hearings.

Experts at two hearings sounded a mix of optimism and caution.

“Much more needs to be done,” warned John Holdren, director of the president’s Office of Science and Technology Policy. “In general, detection of NEOs [near-Earth objects] and prediction of future orbits are challenging endeavors, especially when one considers that orbits can change as a result of encounters with other objects.”

In his prepared testimony, he said that almost every day, “at least one 10-meter near-Earth asteroid (part of the undiscovered population of about 50 million) passes the Earth inside the orbit of the Moon.”

The Chelyabinsk object, characterized by scientists as a small asteroid, had an estimated size of about 17 meters.

The importance of understanding asteroids – including how to deflect them away from Earth if needed – is one reason the National Aeronautics and Space Adminstration is planning a mission to “lasso” an asteroid and bring it close enough for an astronaut visit by 2025.

"NASA has determined that it is unlikely that the world will suffer a global catastrophic impact over the next several hundred years similar to the dinosaur extinction event," NASA Administrator Charles Bolden told the House Committee on Science, Space, and Technology.

NASA is still in the process of cataloging the largest near-Earth objects. And some scientists at the hearings noted the need for more global resources, beyond the US, to be devoted to the issue.

To safeguard Earth, a key goal is to use ground- and space-based equipment to identify near-Earth objects that are larger than 140 meters, determine which represent potential threats, “and do so with enough time to either deflect the object, or warn of its arrival,” Donald Yeomans of NASA’s Jet Propulsion Laboratory told one of the hearings this spring.

The asteroid 1998 QE2 is one of the already known objects. NASA says the asteroid won’t pass so close to Earth again for 200 years.