Radar reveals asteroid’s ‘puzzling structures’

LOS ANGELES – The largest asteroid to pass close to Earth in decades hurtled by Tuesday afternoon, appearing as only a faint streaking glow on your average telescope but lighting up NASA’s powerful radar screens.

The 1,300-foot-wide asteroid came within roughly 201,000 miles of the planet, within the moon’s orbit but never posing a threat, allowing NASA scientists at the Deep Space Network antenna in the Mojave Desert their closest peak ever at such a massive space rock.

The radar images were detailed enough to allow the NASA’s Jet Propulsion Laboratory, based in La Canada Flintridge …

LOS ANGELES – The largest asteroid to pass close to Earth in decades hurtled by Tuesday afternoon, appearing as only a faint streaking glow on your average telescope but lighting up NASA’s powerful radar screens.

The 1,300-foot-wide asteroid came within roughly 201,000 miles of the planet, within the moon’s orbit but never posing a threat, allowing NASA scientists at the Deep Space Network antenna in the Mojave Desert their closest peak ever at such a massive space rock.

The radar images were detailed enough to allow the NASA’s Jet Propulsion Laboratory, based in La Canada Flintridge, Calif., to create a short video of the spinning asteroid as it approached.

“The animation reveals a number of puzzling structures on the surface that we don’t yet understand. To date, we’ve seen less than one half of the surface, so we expect more surprises,” said radar astronomer Lance Benner, the lead scientist on the project.

NASA blasted the asteroid with microwaves from a radio telescope near Barstow, Calif., using the 230-foot-wide aluminum dish to receive signals bouncing off the asteroid. That data revealed its ridges, craters and boulders and provided enough information about its speed, trajectory and physical characteristics to allow JPL officials to plot its course for the next 64 years.

Benner said the data show that the asteroid – named 2005 YU55 – will have another close encounter with earth in 2075. It will skim close to Venus in 2029.

The close proximity gives researchers a rare opportunity to study the physical characteristics of a massive asteroid.