A meteor falls out of the sky, creating an incurable dent in the chalkboard. The ambient temperature of the classroom is 70F. Five minutes after impact, an errant paper airplane touching the meteor bursts into flame, whence it is deduced that the temperature is then 451F.

Fifteen minutes after impact, a careful measurement of the meteor reveals that it has cooled to 260.5F.

What was its temperature at the time of impact? An hour after the impact?

Recall that the difference in temperature to ambient surroundings decays exponentially with time.