To find out how far the comet will travel in 10 hours, we can first determine its speed. The speed can be calculated using the given distance traveled in 4 hours:
\[ \text{Speed} = \frac{\text{Distance}}{\text{Time}} = \frac{8000 \text{ miles}}{4 \text{ hours}} = 2000 \text{ miles per hour} \]
Now, we can calculate the distance the comet will travel in 10 hours using the speed:
\[ \text{Distance} = \text{Speed} \times \text{Time} = 2000 \text{ miles per hour} \times 10 \text{ hours} = 20000 \text{ miles} \]
Thus, the comet will travel 20000 miles in 10 hours.