Question 1

How far is a light-year in km?

Accepted Answer

A light-year is 9.461 trillion km (9.461 × 10¹² km). The nearest star, Proxima Centauri, is 4.24 light-years away.

Question 2

How long would it take to travel a light-year?

Accepted Answer

At Voyager 1 speed (17 km/s), about 17,500 years. At 1% light speed, 100 years. Current technology cannot approach these speeds.

Question 3

Is this conversion factor exact?

Accepted Answer

Metric-to-metric conversions are exact (1 km = 1000 m). Imperial-to-metric factors like 1 inch = 2.54 cm are exact by international agreement.

Question 4

Why do some countries use different units?

Accepted Answer

Historical reasons - the metric system spread from France after 1795. The US, UK, and a few others retained older systems. Science uses metric worldwide.

Light Years to Kilometers Converter

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