A Wonderleaf question
Why do stars twinkle?
a real page from the book
Stars twinkle because their light crosses Earth's moving atmosphere before it reaches your eyes. Uneven layers of warm and cool air bend the beam again and again, so the star seems to brighten, fade, and wobble. The star itself is steady.
Planets usually look calmer because they are near enough to show a tiny width, not just a point. Light from one edge may be nudged one way while light from another edge is nudged differently, and your eye blends the tiny changes together.
Wonder words
- atmosphere
- starlight
- telescope
- planet
Try it out
Look outside for a bright planet and a star, then see which one seems steadier to your eyes.
Read the whole picture book
Watercolour scenes, straight answers, about three minutes cover to cover.
Open the picture bookOne more wonder: Why is space so dark?
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