“An aircraft carrier-sized asteroid will make a safe, close flyby of Earth…”

If the calculations are correct, the 400m-wide asteroid 2005 YU55 will make a safe, close flyby of Earth at around half past eleven tonight (11.28pm GMT).  [If?! – Ed]  If not, we’ll have a wondrous new scar to boast about! 

Radar image of asteroid 2005 YU55 obtained on Nov. 7, 2011, at 11:45 a.m. PST (2:45 p.m. EST/1945 UTC), when the asteroid was at 3.6 lunar distances, which is about 860,000 miles, or 1.38 million kilometers, from Earth. [Image credit: NASA/JPL-Caltech]

And with its projected path inside the Moon’s orbit.

From the JPL press release

Radar observations from the Arecibo Planetary Radar Facility in Puerto Rico will begin Nov. 8, the same day the asteroid will make its closest approach to Earth at 3:28 p.m. PST (6:28 p.m. EST/1128 UTC).

The trajectory of asteroid 2005 YU55 is well understood. At the point of closest approach, it will be no closer than 201,700 miles (324,600 kilometers) as measured from the center of Earth, or about 0.85 times the distance from the moon to Earth.  The gravitational influence of the asteroid will have no detectable effect on Earth, including tides and tectonic plates. Although the asteroid is in an orbit that regularly brings it to the vicinity of Earth, Venus and Mars, the 2011 encounter with Earth is the closest it has come for at least the last 200 years.

It’s also the closest approach by an asteroid of this size that we’ve known about in advance.  The last fly-by of something of this size was in 1976, the next will be in 2028.  That we know of…

Other, more recent, close fly-bys have been by much smaller asteroids.  In this short video from JPL News, research scientist, Lance Benner, provides the details

Update Well, we’re still here. [So the calculations were correct?! – Ed] Apparently so. And here’s a short animated video of asteroid 2005 YU55 by NASA’s Jet Propulsion Laboratory. The data was obtained Nov. 7, 2011 using NASA’s Goldstone Solar System Radar (located at the Deep Space Network facility in Goldstone, Ca.) At the time, asteroid 2005 YU55 was approximately 860,000 miles (1.38 million kilometers) away from Earth.  Resolution 4 metres per pixel. Via JPL News.

Pete Baker