That width is less than the distance I drive from my house to the grocery store. Why was that size of an asteroid able to cause such catastrophic damage?
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Kinetic energy is 0.5mv^2, so is proportional to mass. Double the mass, double the kinetic energy.
Kinetic energy is proportional to the square of velocity. Double velocity, quadruple the energy.
Objects in solar orbit are generally going very very fast with respect to earth. So even an object with small mass has tremendous kinetic energy.
For example, the object that struck the Barringer crater in Arizona was only about the size of a 747 in terms of radius (but was much more massive being a non-hollow rock). https://en.wikipedia.org/wiki/Meteor_Crater?wprov=sfla1
That object struck with so much kinetic energy that the entire object not only _melted_ from the heat but _evaporated_ from the heat of the impact. So a hunk of iron bigger than a 747, at the moment of impact, turned into iron _gas_. Gases take up a lot more volume by mass than liquids and solids. Gases approximately follow the ideal gas law, PV=nRT, at any given moment. So at the moment of impact, temperature T spiked enough to turn solid iron into gas iron. So the left-hand side of this equation suggests that either pressure P or volume V had to spike also. But at the precise moment of impact, the meteor still occupied almost the same volume as the moment before. So it must have been pressure that spiked. So, the gas expanded explosively. By turning from a solid to a gas at the moment of impact, the meteor basically exploded into a huge cloud of iron gas.
As it expanded, the gas iron cooled into molten iron, which rained down for miles around the impact site.
Now apply the same thing to an object several miles across, and you get an event that shakes tectonic plates and lays down a layer of metal across the entire surface of the planet. The layer from the dinosaurs’ extinction event is known as the KT boundary.
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