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[DD1975]

regarless of the size, what was scary was that it was only spotted 7 days before passing.

It just shows how important the NEOshield research actually is!!

[DaveMorton]

Just watched Horizon: The good, the bad, and the ugly. It was about asteroids

The Tunguska event in 1908 was estimated at 1-10 mega ton explosion and estimated to be about 30-50 meter asteroid.

I revise my blasé comment in the previous post about a 13m asteroid.

Yeah, I don't think that an asteroid that measures 13 meters across would "mostly burn off", especially if it were composed of dense nickel/iron, like most asteroids are. By the time it hit the ground, I'm guessing it would still be roughly 10 meters across, and depending on speed, could produce an impact force of 100 to 1,000 kilotons, which could easily level anything from an entire city block to a few square miles or more. The town I grew up in would probably be completely vaporized, should something that size make a surprise appearance. Of course, said town has a population of only 500 people, but still...

[Snowcrash]

The real scarey bit is not the impact but the high winds from the detonation.

The Tunguska event was an air burst as well and leveled many square miles on forest. Would level most cities if in the wrong place.

Here's a link for those who have never heard of it.

[Legion]

Near-miss asteroid will return next year, even closer

When it whizzes past Earth in 2013, a newly discovered asteroid is going to miss our planet -- but not by much.  The 50-meter space rock is expected to come closer than many satellites, highlighting the growing need to keep watch on hazards from above.
Source: Near-miss asteroid will return next year, even closer

[Snowcrash]

A new PHA coming up.

Name          Date of          Distance (LD = Lunar Distance)
                  closest               and Size
                  approach

2012 EG5   Apr 1      0.6 LD and 62 meters across.

Been doing a little homework. 20-30 meters (almost the same as yards) will tend to burn up. 50m is roughly the size of what caused the Barringer Crater (also known as meteor crater) and the Tunguska. The difference being, Barringer Crater was an iron meteor and Tunguska was an ice meteor/comet.

[DaveMorton]

Thanks for the info, Snowy! great stuff!
I've been to the Barringer Meteor Crater a couple of times, and have every intention of visiting again some day. The place is both breathtakingly beautiful and humbling, and is one of the reasons why I love the field of astronomy so much. It's staggering to think that something so small (cosmically speaking, that is) can do so much damage.

Google visited last this page May 17, 2012, 07:08:10 AM