To determine how far the comet will travel in 10 hours, we first need to find its speed in miles per hour.
Given that the comet travels 8,000 miles in 4 hours, we can calculate its speed:
\[ \text{Speed} = \frac{8,000 \text{ miles}}{4 \text{ hours}} = 2,000 \text{ miles per hour} \]
Now, we can use this speed to find out how far the comet will travel in 10 hours:
\[ \text{Distance} = \text{Speed} \times \text{Time} = 2,000 \text{ miles per hour} \times 10 \text{ hours} = 20,000 \text{ miles} \]
Thus, the comet will travel 20,000 miles in 10 hours.