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View Full Version : How big would an asteroid have to be to destroy earth?



Heroin
2004-Jan-21, 01:27 AM
How big would an asteroid have to be to destroy earth? How likely is that to happen?

Sparks
2004-Jan-21, 01:32 AM
To destroy the planet, to wipe out all life on the planet, or just to wipe us out?

Heroin
2004-Jan-21, 01:36 AM
To destroy the planet, to wipe out all life on the planet, or just to wipe us out? just all life forms on earth

Sparks
2004-Jan-21, 01:39 AM
Depends on the impact speed, the impact site and the composition of the asteroid.
A nickel-iron asteroid 10km in diameter sounds about right though.

Heroin
2004-Jan-21, 01:42 AM
ok thank you

semi-sentient
2004-Jan-21, 03:01 AM
13?

8-[

tuffel999
2004-Jan-21, 03:03 AM
Exactly just hadn't gotten here yet.

So here it is.

13 :wink:

Taibak
2004-Jan-21, 03:53 AM
To help put things into perspective....

When a meteor hit and the dinosaurs went extinct, most of the life on the planet went with them. The Earth isn't exactly barren now.

The Moon was formed when a rock the size of Mars slammed into the Earth billions of years ago. That didn't destroy the newborn Earth.

As for how likely it is that it will happen, nobody really knows because nobody really has any idea just how many rocks are out there that are large enough to do it, nor how many asteroids get close enough to the Earth. In all honesty, it's probably only a matter of time before something big hits us. However, this is a bit like using the entire field at Gillette Stadium for a game of marbles. More often than not, things are just going to miss us.

Sparks
2004-Jan-21, 07:01 AM
The Moon was formed when a rock the size of Mars slammed into the Earth billions of years ago. That didn't destroy the newborn Earth.
Weelllll.....
Beforehand, one lump of rock - afterwards, two large pieces and lots of debris.
I know it's not total vapourisation, but we don't have the deathstar to work with here ;)


As for how likely it is that it will happen, nobody really knows because nobody really has any idea just how many rocks are out there that are large enough to do it, nor how many asteroids get close enough to the Earth. In all honesty, it's probably only a matter of time before something big hits us.
I thought there was a figure from Spacewatch of 0.4 for the probability of a 1km diameter asteroid hitting us between the year 1000 and 3000?

Sparks
2004-Jan-21, 07:56 AM
Exactly just hadn't gotten here yet.
So here it is.
13 :wink:
Am I right in assuming that the actual value is somewhat higher? :D

tuffel999
2004-Jan-21, 10:03 PM
Possibly I am not sure of the exact number of times this has been discussed but it could be higher than 13.

Wingnut Ninja
2004-Jan-22, 03:57 AM
I bet something the size of Jupter would do it, more or less.

Charlie in Dayton
2004-Jan-22, 06:45 AM
13?

8-[

Wrong.

42.

ZaphodBeeblebrox
2004-Jan-22, 11:19 AM
13?

8-[

Wrong.

42.

But, of course, Now where did I put my Towel?

=D>

Amadeus
2004-Jan-22, 12:14 PM
Hasn't there just been a discovery of microbes living deep inside the crust?

Lifes a tough little thing. It will always find a way. Even if the planet is smashed to bits there would still be a few microbes clinging to the fragments asking what that noise was.

ToSeek
2004-Jan-22, 04:02 PM
You can play around with various results here (http://janus.astro.umd.edu/astro/impact.html). Sparks' 10 km asteroid would release roughly double the energy of the K/T impactor (the "dinosaur killer").