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NASA captures new images of large asteroid passing Earth

Tracking of the asteroid began at 12:30 p.m. EST November 4, with an additional four hours of tracking planned each day November 6–10.
By Jet Propulsion Laboratory, Pasadena, California, NASA Headquarters, Washington, D.C. Published: November 8, 2011
Asteroid 2005 YU55
New radar image of asteroid 2005 YU55. Credit: NASA
NASA’s Deep Space Network antenna in Goldstone, California, has captured new radar images of asteroid 2005 YU55 passing close to Earth.

The asteroid will fly past our planet slightly closer than the Moon’s orbit November 8. The last time a space rock this large came as close to Earth was in 1976, although astronomers did not know about the flyby at the time. The next known approach of an asteroid this size will be in 2028.

The image was taken November 7 at 2:45 p.m. EST, when the asteroid was approximately 860,000 miles (1.38 million kilometers) away from Earth. Tracking of the aircraft-carrier-sized asteroid began at Goldstone at 12:30 p.m. EST November 4 with the 230-foot-wide (70 meters) antenna and lasted about two hours, with an additional four hours of tracking planned each day November 6–10.

Radar observations from the Arecibo Planetary Radar Facility in Puerto Rico will begin November 8, the same day the asteroid will make its closest approach to Earth at 6:28 p.m. EST.

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.

NASA detects, tracks, and characterizes asteroids and comets passing close to Earth using both ground- and space-based telescopes. The Near-Earth Object Observations Program at the Jet Propulsion Laboratory in Pasadena, California, commonly called “Spaceguard,” discovers these objects, characterizes some of them, and plots their orbits to determine if any could be potentially hazardous to our planet.

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5 stars
JERRY ROSS from MISSOURI said:
RADAR is based on the reflectivity of the object being observed. Therefore areas of higher/lower reflectivity show up as lighter/darker areas on the object. Lighter/darker areas are determined by how the RADAR reflections are presented to the observer. In this case the object is pretty much an orb which will change the amount of reflected energy depending on where the RADAR pulses are reflected from the object. That produces lighter and darker areas. The top area is less reflective so in this case less reflective areas are displayed as lighter areas. Apparently the lower part of the asteroid is not so orb-like as the part shown in the photograph.
MIKE WILLOWS from NEW JERSEY said:
How is it that a radar image would appear lit from the "top"?

Or do I have a completely erroneous concept of the way radar works?
4 stars
DAVID NYE from MONTANA said:
This seems to me to be an extremely close encounter. On the scale of things I would think someone would have mentioned that. An object that size coming within the Earth Moon orbit should bring some concern from those who track it. Am I too concerned?

How far out can we detect and predict the course of an object this size?


Sincerely; Dave Nye bhl@blackfoot.net
5 stars
MR GERALD W MORAN said:
The radar image of asteroid 2005YU55 looks amazing,but seeing how small it is.Its amazing how round it seems to be.
4 stars
RAUL V ESPINOZA from ARIZONA said:
very fine articles!
4 stars
FRED T HOPKINS JR from SOUTH CAROLINA said:
I was set up just before the close encounter and saw the asteroid make its pass low in the sky, while I was looking to the east from my house in Florence, South Carolina. Its color was vaguely reddish-orange and I was surprised to see it so clearly in my 20x80mm binoculars. It made quite an impression. I can't wait to see the close approach of Apophis [sic.] next September!
SHAUN G VAVRA from ILLINOIS said:
this is the first time i ever heard of an astroid this size come between the earth and the moon these days, unless if there has?
5 stars
JOHN GABODA JR from NORTH CAROLINA said:
It's amazing to think that this super-carrier sized asteroid almost slammed into our home. I personally breath a sigh of relief, not because i had any doubt about the mathematics in determining the trajectory of the asteroid, but because we were able to gather a pool of photos and now are learning more about the asteroid. Learning continues and perhaps soon enough we will understand more about these " space rocks".
3 stars
KAVAN DAVE said:
VERY GOOD :)
4 stars
DEAN DENNEY from CALIFORNIA said:
good
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