asteroid disaster

[Sander]

How could an asteroid wipe out the dinosaurs?

[woolley]

Scienetists generally believe that the dinosaurs died as the result of an asteroid which hit Chicxulub in Mexico 65 million years ago. One theory is that clouds of dust hung in the upper atmosphere for months, blocking sunlight and stopping plants growing. But a new study by geologist Kevin Pope from Geo Eco Arc Research in Maryland shows that dust alone could not have caused it. This is because only dust grains which are smaller than a micrometre across stay suspended in the atmosphere, and the ten-kilometre asteroid would not have created enough fine dust to affect the whole world. Kevin Pope thinks that rocks which were vaporised by the impact may have released sulphur and formed formed sulphate aerosols that blocked out the light. The impact at Chicxulub spread a layer of debris around 3mm thick around the world. However, Keven Pope believes that more than 99% of the debris was made up of droplets condensed from the vaporised rock, and only a tiny amount was dust.

[incitatus]

You can extend the effect though. The tunguska explosion caused seismic disruption on the other side of the world. One theory runs that the impact kicked off volcanic eruptions on the oother side of the globe. There are large areas of vulcanism in Asia that fit the general date. The dust emissions from these should make up the missing material....