B612 Foundation Earth Day Impact Video

Things that make you go uh-oh.

B612 Foundation Earth Day Impact Video

Quote :

Between 2000 and 2013, this network detected 26 explosions on Earth ranging in energy from 1-600 kilotons - all caused not by nuclear explosions, but rather by asteroid impacts. To put that in perspective, the atomic bomb that destroyed Hiroshima in 1945, exploded with an energy impact of 15 kilotons. While most of these asteroids exploded too high in the atmosphere to do serious damage on the ground, the evidence is important in estimating the frequency of a potential “city-killer-size” asteroid.

The Earth is continuously colliding with fragments of asteroids, the largest in recent times exploding over Tunguska, Siberia in 1908 with an energy impact of 5-15 megatons. More recently, we witnessed the 600- kiloton impact in Chelyabinsk, Russia in 2013, and asteroid impacts greater than 20 kilotons occurred in South Sulawesi, Indonesia in 2009, in the Southern Ocean in 2004, and in the Mediterranean Sea in 2002. Important to note as well is the fact that none of these asteroids were detected or tracked in advance by any existing space-based or terrestrial observatory.

Are these numbers greater than the historical norm?

I suppose there's no way to know for sure, because it's only recently that we've had the technology to monitor the events. But certainly things were a lot more violent billions of years ago, and I got the impression that they have gradually calmed down since then. But trending down doesn't mean you don't get the occasional uptick. And as the saying goes, it only takes one - one good one in the wrong place.

richard09 wrote:

it only takes one - one good one in the wrong place.

I can think of a city which wouldn't be a bad place.

Scrounging around on the internet, I found a number of sites that write about meteor and asteroid impacts. None of them specifically give the historical numerical data I was looking for to compare with the post Richard09 made, but it would appear that nothing has changed in eons. I was surprised to see the number of rocks that smash into the earth every year.

_Howard wrote:

I was surprised to see the number of rocks that smash into the earth every year.

Most of them are airbursts, rather than actual impacts. But if it gets close to the ground, that's bad enough. And a few miles up is close enough, if the explosion is big enough. Witness the Tunguska event.