why is gravity on earth and not on the moon i need something to help me start it off
Ahh -- but the moon does have gravity.
http://www.moonconnection.com/moon_gravity.phtml
To understand why gravity exists on Earth but not on the Moon, let's start with a basic understanding of what gravity is and how it works.
Gravity is the force that attracts objects with mass towards each other. It is responsible for the phenomenon that makes objects fall to the ground when dropped. The strength of gravity depends on the mass of the objects and the distance between them.
Now, when it comes to Earth and the Moon, the difference lies in their respective masses and sizes.
Earth has a much larger mass than the Moon. This means that Earth has a greater gravitational pull because it has more mass to exert that force. As a result, everything on or near Earth is affected by the gravitational pull towards its center.
The Moon, on the other hand, has a much smaller mass compared to Earth. Consequently, the force of gravity on the Moon is significantly weaker. The Moon's gravitational pull is about one-sixth (1/6) of Earth's. This means that objects on the Moon weigh about one-sixth of what they do on Earth.
To further explain why gravity on the Moon is weaker, you can use the formula for gravitational force, known as Newton's law of universal gravitation:
F = (G * m1 * m2) / r^2
In this formula, F represents the gravitational force, G is the universal gravitational constant, m1 and m2 are the masses of the two objects interacting (in this case, Earth and the Moon), and r is the distance between their centers.
By plugging in the respective values for Earth and the Moon, you can calculate the difference in gravitational force.
So, to answer your question, gravity exists on Earth and not on the Moon primarily because Earth has a much larger mass and therefore a stronger gravitational pull.