Step off a diving board and Earth pulls you down. Nothing touches you on the way. The pull reaches you through empty air.
In earlier grades you saw gravity as the downward pull on objects near Earth. This lesson names what fills the space around Earth. The surprise is how many other objects have one too.
Now consider Earth and the space around it. Earth fills the space around it with a gravitational field.
Earth has mass, so Earth has a gravitational field. The Moon has mass, so the Moon has a gravitational field. An apple has mass, so the apple has a gravitational field too.
A pebble lies on a trail. Does the pebble have a gravitational field around it?
The apple's gravitational field is real, but it is far too weak to notice. Even you have mass, so even you have a gravitational field around you. No object is too small: anything with mass has a gravitational field, however weak.
Mars has mass. Does Mars have a gravitational field around it?
Write down the fact:
Any object with mass has a gravitational field around it.
Mars has mass.
Yes: Mars has a gravitational field.
Signe says her textbook has a gravitational field around it, far too weak to notice. Is Signe correct?
A granite boulder rests beside a trail. Does the boulder have a gravitational field around it?
Write down the fact:
Any object with mass has a gravitational field around it.
The boulder has mass. No object is too small; the field is simply very weak.
Yes: a very weak gravitational field surrounds the boulder.
So Earth's pull on a diver is one example of something universal: every object with mass fills the space around it with a gravitational field.
Which statement about gravitational fields is true?
A wrench drifts in deep space, far from every planet. Which statement is true?
A helium balloon drifts upward. Which statement is true?