Asteroid 2009 DD45 Missed Earth By About 49,000 Miles On Monday - Roughly Size Of Tunguska Object

[hatrack]

PASADENA, Calif. — An asteroid about the size of one that blasted Siberia a century ago just buzzed the Earth.

The asteroid named 2009 DD45 was about 48,800 miles from Earth when it zipped past early Monday, NASA's Jet Propulsion Laboratory reported.

That is just twice as high as the orbits of some telecommunications satellites and about a fifth of the distance to the Moon.

"This was pretty darn close," astronomer Timothy Spahr of the Harvard-Smithsonian Center for Astrophysics said Wednesday. The space rock measured between 69 feet and 154 feet in diameter. The Planetary Society said that made it the same size as the asteroid that exploded over Siberia in 1908 and leveled more than 800 square miles of forest.

EDIT

http://www.huffingtonpost.com/2009/03/04/asteroid-2009-dd45s-passi_n_171722.html

[DemzRock]

1. Too close for comfor... btw...

How is it that the Tunguska asteroid blew up OVER Siberia and not by hitting it? I never understood that one.

[MNDemNY]

2. The heat of entering the earths atmosphere and it's high water(ice) content.

[lapfog_1]

3. Theory is that it superheated on entry into the atmosphere...

and "blew apart" into millions of small gravel sized chunks, thus leaving almost no impact crater but the force of the
explosion knocked down trees for many many miles in all directions.

Had it been made with a solid iron core center, the area would now look more like this:



only bigger.

[phantom power]

6. SciAm had a good article on tunguska last year.

A team of scientists found a lake the fits the profile for a residual impact crater. What was left after the aerial explosion. They were planning to return and try retrieving a fragment from the lake.

[JohnWxy]

4. 49,000 MILES!!! That's too damn close.

[Nihil]

5. Shame.

Better luck next time.

[struggle4progress]

7. Earth Impact Effects Program

http://www.lpl.arizona.edu/impacteffects/

JPL Small-Body Database Browser
http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2009%20DD45;orb=1

You can play with the impacts program; if you need better info, maybe the orbital parameters data helps. Crudely speaking: at 10 km from the impact, you're seriously burned by the fireball radiation and also badly battered by the shock wave; at 100 km from the impact, you hear noise and the ground shakes a bit

If this had been on a collision course, I expect that with the limited notice, and lack of precise information about shape and cohesiveness of the object, there would be no chance of gauging with any precision how this would travel through the atmosphere, whether it would break into smaller pieces, and where the largest fragments might hit

[dbt]

8. The same Tunguska Object of which no trace

has yet been found, yes?

It was Tesla.

:evilgrin:

[Howard T38]

9. Return?

Has anyone seen any info on possible returns?