Asteroid Impacts

[Achán hiNidráne]

Here's a morbid query: I'm working on a sci-fi RPG setting where Earth is struck by an moderately sized asteroid. Not an "Dinosaur Killer," but one that causes a massive disruption of human civilization; economic collapse, war, famine, etc. Can anyone suggest how big such an asteroid should be and where the impact could do the most damage?

I know, it's a weird question. Feel free to mock me for asking it.

 

[cgordon]

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

>Earth Impact Effects Program
>Robert Marcus, H. Jay Melosh, and Gareth Collins
>Welcome to the Earth Impact Effects Program: an easy-to-use, interactive
>web site for estimating the regional environmental consequences of an
>impact on Earth. This program will estimate the ejecta distribution, ground
>shaking, atmospheric blast wave, and thermal effects of an impact as well as
>the size of the crater produced.

 

[Silly Green Monkey]

That one was fun, my friend in the UK put in his details and found that he was part of the ejecta.

 

[wollery]

He he, that really was fun, on my second go I vapourised the Earth and created a new asteroid belt!!!

 

[Carn]

Here's a morbid query: I'm working on a sci-fi RPG setting where Earth is struck by an moderately sized asteroid. Not an "Dinosaur Killer," but one that causes a massive disruption of human civilization; economic collapse, war, famine, etc. Can anyone suggest how big such an asteroid should be and where the impact could do the most damage?

I know, it's a weird question. Feel free to mock me for asking it.

I'm no expert, but i afaik the "dinosaur killer" didn't kill all dinosaurs, just have of them, the rest died the following 10 to 100 thousand years. The point is, that a similar impact today would not be the end of mankind, maybe not even a direct way back to stone age, depending on hit location and time to prepare.

Carn

Edit to add:
According to above link a 10 km dense rock with 20km/s impact speed will not affect someone 5000 km away immiediately in a serious way, so if the pacific is hit US east coast and europe will survive and if atlantic is hit japan and US west coast will survive. In both survival areas, they have enough science knowledge and tech to survive the temperature drop.

 

[Carn]

Can anyone suggest how big such an asteroid should be and where the impact could do the most damage?

As the impact energy can transverse much better through water than stone, an impact in water does normally more damage above(big enough to produce tsunami) and below a certain size than a land impact.
The more people close to shore increases damage, so a pacific hit would be worst, could make china's east coast(80% of their social product), japan and US west coast vanish, the most human and economic damage done. Also pacific is most likely hit area, it's biggest.

Carn

 

[Roboramma]

I'm no expert, but i afaik the "dinosaur killer" didn't kill all dinosaurs, just have of them, the rest died the following 10 to 100 thousand years.

I didn't think the fossil record had that kind of detail (to 10's of thousands of years accuracy...). If it does, that's pretty cool!

 

[Carn]

I didn't think the fossil record had that kind of detail (to 10's of thousands of years accuracy...). If it does, that's pretty cool!

Maybe that was the thought behind what i read, from fossil record one can only prove the death to have happened shortly after the impact and there is simply no mechanism, how a 10 km impacting could kill dinosaurs on the other side of earth immiediately.

Carn

 

[Bikewer]

Ah, read Lucifer's Hammer by Larry Niven and Jerry Pournell. It's kinda been done...

 

[Soapy Sam]

Bikewer is right.

Shallow marine strike seems to be optimal for maximum effect.

Something English Manor House sized in the English Channel would take out london and Paris, most southern N.Sea gas fields and some northern N.Sea oil pipelines and platforms. Could trigger secondary slides along the Norwegian continental shelf , too. Lots of shipping losses - some of the cargoes might be toxic , too.
Economic and environmental damage immense. Trillions wiped off stock values. Immense disruption of economic / banking / insurance services.
South East England, the Paris Basin, much of the Netherlands / Rhine Delta underwater.

You could blame it on the Tartan Army. (Space Division.)

 

[Achán hiNidráne]

Ah, read Lucifer's Hammer by Larry Niven and Jerry Pournell. It's kinda been done...

Well, the setting wasn't going to be as apocylptic as that. The Earth would only be plunged into a brief Dark Age before getting back on track. Then would come the renewed interest in space, the discovery of FTL drive, first contact with aliens, etc..