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Light-Years Across Space
Age 14 · Astronomy
A light-year is the distance light travels in one year. It helps measure the huge gaps between the Sun, other stars, and galaxies.
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In the picture
- The Sun: the nearest star, the starting point of the scale.
- A planet beside the Sun: one world in the solar system.
- The glowing beam: the distance light travels in one year.
- The distant star: a sun far beyond the solar system.
- The spiral galaxy: a vast collection of stars far beyond single stars.
Examples
- Sunlight takes about 8 minutes to reach Earth.
- Light from the nearest star beyond the Sun takes about 4.2 years to reach us.
Key takeaways
- A light-year measures distance, not time.
- Light travels about 9.5 trillion kilometers in one year.
Quiz: Light-Years Across Space (Age 14)
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Which of these does a light-year measure?
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About how far does light travel in one year?
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What does a light-year help measure?
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