Why do solar eclipses look so perfectly sized from Earth?
Quick Answer
The Moon is about 400 times smaller than the Sun but also about 400 times closer, so they appear nearly the same size in the sky.
The Full Story
A total solar eclipse happens because the Sun and Moon look almost identical in angular size from Earth. The Sun is about 1.39 million km wide and roughly 150 million km away, while the Moon is about 3,474 km wide and about 384,400 km away on average. That near match lets the Moon cover the Sun’s bright disk for a total eclipse when alignment is exact. The effect is temporary, because the Moon is slowly moving away from Earth by about 3.8 cm per year, so total eclipses will eventually become rarer.
Key Facts
YouTube Angle
Suggested video title for this topic:
"The Moon and Sun look the same size by cosmic coincidence."
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