How to Watch Enormous Asteroid Zoom By Earth
Earlier today, the massive asteroid 2004 BL86 passed by Earth, coming within 745,000 miles of our planet.
According to NASA officials, the asteroid, which is a staggering 1,800 feet wide, made the closest pass by such a large space rock until 2027.
Although the asteroid's nearest pass has already happened, scientists at NASA's Near-Earth Object Program say that the best time to catch a glimpse of it will be about three hours after sunset, approximately 8 p.m. to 1 a.m. ET tonight.
They expect that 2004 BL86 will not be visible to the naked eye, but small telescopes and strong binoculars could be able to get a view, weather permitting. Asteroid-watchers should look to the east, as the asteroid flies from south to north.
Phil Keating reported on "America's Newsroom" today that astronomers worldwide are eager to study 2004 BL86 to pinpoint its orbit, observe its surface and even look for moons.
"It is huge, the size of a mountain, about a third of a mile wide," Keating said. "It is on the same orbit plane as Earth is, going around the sun."
"Critically important here, this mammoth asteroid is not going to hit Earth. Humanity will be spared."
"For objects that get this close, that are this large, the radar observations are really analogous to a spacecraft flyby in terms of the caliber of the data that we can get," said Lance Benner of NASA's Jet Propulsion Laboratory in Pasadena, California, who is the principal investigator for the Goldstone observations of the asteroid.
The resulting black-and-white images can reveal unprecedented details about asteroids, whereas most ground-based telescopes would see only a point of light. But the first item on the team's checklist will be to nail the space rock's location in space and time. This will enable a better understanding of the object's orbit and its future motion, scientists say.
The researchers expect to obtain resolutions as fine as 13 feet per pixel, so the images of 2004 BL86 should reveal details as small as the length of a typical car. This will allow the scientists to assess how rugged or smooth the space rock's surface is.
"It's expected to be one of the best radar-imaging targets of this calendar year," Benner said.
If Benner and his colleagues get enough images as the object spins, they can start to reconstruct its three-dimensional shape in order to understand how it rotates. They also plan to search for any moons in tow. About 17 percent of asteroids in 2004 BL86's size range tend to have smaller objects trailing along with them.
The Goldstone antenna will track the asteroid for 5 to 6 hours most nights from Jan. 27 to Feb. 1. The Arecibo Observatory, however, will only be able to spot 2004 BL86 on the night of Jan. 27. Its radar is not fully steerable, and the space rock will be zipping through the sky at 2 degrees (roughly four times the width of the moon) per hour.
"The thing that excites us the most is that we don't know anything about it, but it's likely that we'll learn a great deal and see a lot of detail," Benner said. "Whenever one of these objects comes really close like this, it offers such an outstanding opportunity — we almost always see things we haven't seen before. And so we're expecting some kind of surprise."
Watch more above.