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Science

How do solar eclipses happen?

A solar eclipse happens when the Moon passes directly between the Sun and Earth, casting its shadow on us. For a few minutes, the Moon blocks the Sun's light, turning day briefly to twilight along a narrow path.

See it in motion.
Watch a 2-minute animated lesson that shows exactly how solar eclipses works.
▶ Watch the visual lesson

Step by step

  • 1The Moon moves between the Sun and Earth.
  • 2Its shadow falls on part of Earth's surface.
  • 3People in the shadow's path see the Sun partly or fully blocked.
  • 4It only happens at a new moon, when alignment is just right.

Frequently asked questions

What causes a solar eclipse?
The Moon passing directly between the Sun and Earth, blocking the Sun's light and casting a shadow on Earth.
Why don't eclipses happen every month?
The Moon's orbit is tilted, so it usually passes above or below the Sun rather than directly in front.
Is it safe to look at a solar eclipse?
No — looking directly at the Sun can damage your eyes; use certified eclipse glasses.

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