Q
If you're traveling at the speed of light, what happens when you turn on your headlights?
A
Expert Answer
According to special relativity, you can't reach light speed if you have mass (it would require infinite energy). If you could, light from your headlights would still appear to travel at light speed relative to you—one of relativity's counterintuitive predictions.
Key Insight
According to special relativity, you can't reach light speed if you have mass (it would require infinite energy).
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