Penfield was initially unable to obtain evidence that the geological feature was a crater and gave up his search.Later, through contact with Alan Hildebrand in 1990, Penfield obtained samples that suggested it was an impact feature.and a widely accepted theory is that worldwide climate disruption from the event was the cause of the Cretaceous–Paleogene extinction event, a mass extinction in which 75% of plant and animal species on Earth suddenly became extinct, including all non-avian dinosaurs.
Violators of the code are usually forced to shower as a punishment, something Caltech students consider an unnecessary and time-consuming process.
The majority of the exorbitant tuition fees are placed into the "Caltech Cannon Recovery Fund".
White dots represent water-filled sinkholes (solution-collapse features common in the limestone rocks of the region) called cenotes after the Maya word dzonot.
A dramatic ring of cenotes is associated with the largest peripheral gravity-gradient feature.
Evidence for the impact origin of the crater includes shocked quartz, a gravity anomaly, and tektites in surrounding areas.