Light year is a unit of ______________.

Answer

**Step-by-Step Solution:**

1. **Understanding the Term "Light Year":**
- A light year is a term used in astronomy to measure vast distances in space.

2. **Definition of Light Year:**
- A light year is defined as the distance that light travels in a vacuum in one year.

3. **Calculating the Distance:**
- Light travels at a speed of approximately 299,792 kilometers per second (or about 300,000 km/s).
- To find the distance light travels in one year, we can use the formula:
\[ \text{Distance} = \text{Speed} \times \text{Time} \]
- The time in one year is:
\[ 1 \text{ year} = 365 \text{ days} \times 24 \text{ hours/day} \times 60 \text{ minutes/hour} \times 60 \text{ seconds/minute} = 31,536,000 \text{ seconds} \]

4. **Calculating the Light Year:**
- Now, substituting the values into the formula:
\[ \text{Distance} = 299,792 \text{ km/s} \times 31,536,000 \text{ seconds} \]
- This gives us the distance in kilometers that light travels in one year.

5. **Conclusion:**
- Therefore, the answer to the fill-in-the-blank question is:
**Light year is a unit of distance.**

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