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Mercury is the smallest
planet in the solar system.
And it just keeps getting
smaller. Scientists think it has
shrunk up to a mile (2
kilometers) since it formed.
Because Mercury is so
small, it has very little
gravitational pull. That means
it can’t hold on to much of an
atmosphere
—the layer of
gases around a planet.
The surface of Mercury looks a lot like our Moon. Some
areas are covered with
craters
. Other areas are smooth.
The little planet takes just eighty-eight Earth
days
to go
around the Sun. That’s the shortest
year
in the solar system.
But a day on Mercury—the time it takes to spin once—is as
long as two months on Earth. Wow!
Mini
Mercury
