A Wonderleaf question
How big is the universe?
a real page from the book
From Earth, the measurable universe spans about 93 billion light-years. That is not the universe’s full size; it is the distance light has managed to cross toward us while space has been expanding. The whole thing may be much bigger, and it might have no edge at all.
One lovely catch is that distance in space is also time. When you look at Andromeda, you are seeing light that started traveling before modern humans were around. Telescopes are a kind of looking-back machine, collecting old starlight so carefully that it can tell us where we live.
Wonder words
- galaxy
- light-year
- telescope
- expanding
Try it out
Stand outside after dark, pick one star, and imagine its light leaving long before tonight to reach 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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