Astronauts get taller in space.
宇航员在太空里会悄悄变高。
They can grow a few centimeters.
他们能长高好几厘米呢。
Why? There is no gravity up there.
为什么呀？那里没有重力。
On Earth, gravity pushes your body down.
在地球上，重力把身体往下压。
In space, your backbone can stretch out.
在太空，你的脊椎就能舒展开。
The space between the bones gets bigger.
骨头和骨头之间，空隙变大了。
When they come home, they shrink back.
等回到地球，他们又缩回去啦。
