A scientist who studies the stars and other objects in the sky
astronomer
a spacecraft that carries scientific instruments that can collect data, but has no human crew
space probe
Center of the earth
core
A force that pulls objects toward each other
gravity
The path of an object as it revolves around another object in space
orbit
Anything that has mass and takes up space
matter
The length of a path between two points
distance
A straight line passing from side to side through the center of a circle or sphere.
diameter
the outside layer; the top
surface
A large round pit caused by the impact of a meteoroid.
craters
(adj.) one of a kind; unequaled; unusual; found only in a given class, place, or situation
unique
objects, such as those in space or on Earth.
bodies
inside
inner
external
outer
