Why is looking at a star in the night sky like seeing back into time?

Explanation

### Step-by-Step Solution:

1. **Understanding Light Travel Time**:
- Light travels at a finite speed, approximately 299,792 kilometers per second (or about 300,000 kilometers per second). This means that light from distant stars takes time to reach Earth.

2. **Distance of Stars**:
- Stars are located at vast distances from Earth, often measured in light-years. A light-year is the distance that light travels in one year. For example, if a star is 4 light-years away, the light we see from that star today actually left it 4 years ago.

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