How Are Kinetic Energy & Gravity Tugs the Same?

Asteroid Basics

• Objects have energy when in motion. Asteroids have a large amount of kinetic energy. A 10 kilometer-diameter asteroid can strike the Earth's crust at 15 to 20 kilometers per second. This impact generates energy as large as that of 300 million nuclear weapons and creates temperatures greater than the sun's surface, creating widespread destruction and death.

Gravity Tug

• Fortunately, scientists have conceived of a method of preventing asteroid Armageddon by using dense rockets to generate a gravitational pull that gently tugs the asteroid out of the path of the Earth. The rocket would travel near the asteroid and would use its mass to pull at the asteroid for over a year. This pull would gradually shift the asteroid's direction so it flies past the Earth, instead of crashing into it.

Gravity and Energy

• Gravity normally generates potential energy, which is different from kinetic energy. Potential energy is the energy stored within an object. Potential energy is created by the act of the larger object with the gravitational force pulling the smaller objects to them. As a smaller object gets closer to the object attracting it, the object's potential energy decreases and the kinetic energy increases, with the difference in kinetic energy being equal to the difference in kinetic energy. The gravity tug changes the direction of the asteroid, pushing the kinetic energy in a different direction. The gravity tug also generates kinetic energy between the asteroid and the rocket.

Differences

• Fundamentally, the gravity tug is a process of pulling an asteroid, while kinetic energy is a natural phenomenon. Gravity tugs create kinetic energy, but they're built on more physics principles than kinetic energy alone. Theoretically, a gravity tug could increase the kinetic energy of the asteroid by pulling it in the direction it's already traveling, while the tug could reduce the asteroid's kinetic energy by pulling it in the opposite direction.

Kinetic Energy Manifestations

• Kinetic energy is not always noticeable until the object with kinetic energy strikes something. For example, when a child throws a baseball at a window, the ball may have less kinetic energy than whether a professional baseball player hits the baseball at the window with a bat. In the first case, the kinetic energy might cause the ball to make a noise, while in the second case, the kinetic energy will likely shatter the glass.