Asteroid Impact: Risk of Debris & Intact Objects on Earth

[projection]

Is the biggest danger of an asteroid hitting Earth the debris released from the asteroid? Looking at general articles it seems that the global risk arises from the debris released into the atmosphere which would affect climate.

What would happen if no debris was released? I mean, if the object that hit Earth remained intact. Like in a sci-fi film you have a spaceship that crashes onto earth. If the object is made of a metal strong enough to remain intact, would it still be a global event from the debris generated from the Earth? Or would it just be felt in the locally.

 

[D H]

That vast majority (> 99.9%) of the ejecta from a moderate-sized to large impactor comes from the Earth itself. Regarding your "metal strong enough to remain intact": Another name for that metal is unobtanium. Scientists haven't quite nailed down the exact characteristics of this material precisely because it is unobtainable.

Large impactors tend to vaporize on impact. Even moderate sized ones tend to do so. Meteor Crater, Arizona is good example. This crater was caused by an impactor with a diameter of about 50 meters. The impact created a crater 2000 times larger (in volume) than the impactor itself. The impact was the equivalent of about 700 Hiroshima bombs all concentrated in one space.

 

[JesseC]

If it hit the ocean, which is highly likely, there is also the mega-tsunamis. The heat generated also has the potential to start enormous forest fires.

 

[DrClapeyron]

What about an impact so powerful that it triggers massive earthquakes, tsunamis and creates volcanic activity like the Siberian Traps? I would imagine something like that if the bolite was not destroyed upon intrance or impact.