A small asteroid, designated MPEC 2013 PS13 and first detected on August 4, is scheduled to pass within 0.52 Lunar Distance of the surface of Earth on Friday, August 9, 2013. Not many get that close. The Minor Planet Center reports 24 observations establishing the body’s path and size.
This one will be hard to see. It is estimated to be between 5 and 19 meters in length. (It’s hard to tell. Asteroids are dark, they are irregularly shaped and they move pretty fast.) But it nevertheless serves as a reminder that we have projects watching the skies and those projects are important and should be supported.
For more information and links, visit the Minor Planet Center’s NEO Page (Near Earth Objects Page).
Assuming the asteroid has a diameter of 12 meters, a density equivalent to porous rock, a velocity of 20 kilometers/second, and an atmospheric entry angle of 45 degrees, this is what would happen if it collided with Earth:
The projectile begins to breakup at an altitude of 75100 meters = 246000 ft
The projectile bursts into a cloud of fragments at an altitude of 35300 meters = 116000 ft.
The residual velocity of the projectile fragments after the burst is 15.3 km/s = 9.5 miles/s.
The energy of the airburst is 1.13 x 10^14 Joules = 0.27 x 10^-1 MegaTons.
No crater is formed, although large fragments may strike the surface.
The average interval between impacts of this size somewhere on Earth is 13.4 years.
Robert: Thanks. That sounds about right. I think the Chelyabinsk Meteroid earlier this year was a little bigger and came in very shallow.