Dr. Michael Shara, an astrophysicist from the American Museum
of Natural History, says:
Ever heard of Newton’s Law of Gravity? The famous mathematician Isaac Newton came up with this description of the force of gravity between two objects over 300 years ago. Today, scientists are still using it to describe the how objects move in space. For example, they use it to:
• Calculate the orbits of the Space Shuttle
The law can be shown with the formula:
What does this mean? First, let’s look at what the letters represent:
Keep in mind that there’s always a gravitational pull between any two objects. Scientists use this formula to figure out how big the pull is. Newton’s Law of Gravity shows two important ideas:
Even though the Earth’s mass is a lot smaller than the Sun’s,
the Earth is much closer to us so its gravity overwhelms the Sun’s.
That’s why the Earth has a much stronger pull on us than the Sun
and why we stay firmly on the ground instead of flying off!