To determine how far the comet will travel in 10 hours, we first need to find its speed based on the distance it travels in 4 hours.
The comet travels 8,000 miles in 4 hours, so we can calculate its speed as follows:
\[ \text{Speed} = \frac{\text{Distance}}{\text{Time}} = \frac{8000 \text{ miles}}{4 \text{ hours}} = 2000 \text{ miles per hour} \]
Now, we can use this speed to calculate how far the comet will travel in 10 hours:
\[ \text{Distance in 10 hours} = \text{Speed} \times \text{Time} = 2000 \text{ miles per hour} \times 10 \text{ hours} = 20000 \text{ miles} \]
Therefore, the comet will travel 20,000 miles in 10 hours.