Self-study
Selena: Asteroid impact on the Earth caused the extinction of the dinosaurs by raising vast clouds of dust, thus blocking the Sun's rays and cooling the planet beyond the capacity of the dinosaurs, or perhaps the vegetation that supported them, to adapt. █ █████████ ████ █████ ████████ ████████ ██ ████████ ██████ ██ █████████████ ███ ███████ █████ ███ █ ████ ██████ ██████ ██ ███ ████ ██ ███ ████████ █████████ ██ ███████
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Summary
The author concludes that the extinction of the dinosaurs was not due to asteroid impact on Earth.
Why?
Because the asteroid crater in the Yucatan peninsula in Mexico isn’t large enough to create enough dust to block out the Sun’s rays and to cause the planet to get too cold for the dinosaurs to survive. Also, the extinction of dinosaurs took many years.
Notable Assumptions
Trent assumes that the asteroid that hit the Yucatan could not have caused extinction of the dinosaurs through some other method besides dust. (This overlooks the possibility that the asteroid could have killed the dinosaurs through some mechanism besides dust blocking the Sun’s rays.)
Trent assumes that the asteroid that hit the Yucatan was the only asteroid that could have contributed to the amount of dust in the atmosphere. (This overlooks the possibility that a different asteroid, or multiple asteroids together, could have created enough dust to block out the Sun’s rays.)
Trent assumes that dust created by a single asteroid cannot last the many years required for the dinosaurs to go extinct.
17.
Trent's argument assumes that
a
any collision of ██ ████████ ████ ███ █████ █████ ████ ████████ ██ █ ████ ████ ██████ ████ ██ █████
Not necessary, even if some asteroids could have occurred in the ocean, that doesn’t undermine Trent’s reasoning. It’s still the case that the Yucatan asteroid didn’t create enough dust, and that still constitutes a reason to doubt asteroids as the cause of dinosaur extinction.
b
dinosaurs in the ████████████ ██ ██ ████████ ██████ ███ ███ ██████ ███ ████ ██ ██████ ██████ █████ ████ ████████ ████ ██ ██████
Not necessary, because even if dinosaurs in the neighborhood of an asteroid impact, but outside the direct impact zone, still would have died, that doesn’t undermine Trent’s reasoning. Trent’s argument is that the Yucatan asteroid didn’t create enough dust to block out the Sun’s rays and cool the planet beyond the capacity of dinosaurs to survive. He could agree that the asteroid killed many dinosaurs around the impact; the point is that it didn’t create enough dust to kill dinosaurs worldwide.
c
any event that █████ █████ ████ █ ████ ██████ ██ ████ ███ ████ █████████ █████ ██ ██████
Trent never argues that the dinosaur extinction had “many different causes.” He simply believes it wasn’t caused by asteroid impact.
d
dust from the ██████ ██ ██ ████████ ██ ███ █████ █████ ███ ████ ███ ███ ███████ ██████ ██ ███ ███████
Not necessary, because Trent can agree that the dust from the impact of the Yucatan asteroid had a cooling effect on the climate. His point is that there wasn’t enough dust to make the world cold ENOUGH to kill dinosaurs.
e
no more than ███ █████ ████████ ██████ ███ █████ ██████ ███ ██████ ████ ███ █████████ ████ ████████ ███████
Necessary, because if this were not true — if MORE than one large asteroid struck Earth during the period when the dinosaurs were becoming extinct — then the fact that the Yucatan asteroid couldn’t have created enough dust by itself to kill the dinosaurs does not establish that the extinction wasn’t caused by asteroid impact. Perhaps the Yucatan asteroid plus another asteroid together could have created enough dust to kill the dinosaurs.