THE LARGEST ASTEROID PAST EARTH IN A FAINT GLOW

LOS ANGELES, U.S.A. - The 1,300-foot-wide asteroid came within roughly 323,478km of the planet, within the moon's orbit. Posing no threat to Earth, it allowed Nasa scientists at the Deep Space Network antenna in the Mojave Desert their closest peek ever at such a massive space rock.
The largest asteroid to pass close to Earth in decades hurtled by on Tuesday afternoon, appearing as only a faint streaking glow on your average telescope but lighting up Nasa's powerful radar screens.
The radar images were detailed enough to allow Nasa's Jet Propulsion Laboratory, based in La Canada Flintridge, 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, 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.
• Its proximity gives researchers a rare opportunity to study the physical characteristics of a massive asteroid, adding to the research and understanding of bodies floating in space and offering a glimpse, perhaps, of the forces that created the universe, Benner said.

Robert S McMillan (left photo), the University of Arizona scientist who discovered the asteroid, said the orbits, size, shape and mechanical structures of these ‘near-Earth objects' provide clues to their origins and may help explain how they escape the asteroid belt between Mars and Jupiter. "We know the orbit extremely well," McMillan said on a webcast.

Source: Agency