Bixuan Sang Chunshan Jiang Xuan Huang

1. Bixuan Sang • Chunshan Jiang • Xuan Huang • Jiaxun Wang Group members:

2. What is Gravitation • Gravitation, or gravity, is an attractive force between two objects which have mass. • Gravitation is known as one of the four fundamental interactions of nature. • Newton’s law of universal gravitation provides an accurate approximation for most gravitation’s calculations.

3. Being Developed… • Isaac Newton initially developed a quantitative theory of gravitation. • the force of attraction between two bodies is related to their masses and the distance between them, given as: • Albert Einstein then showed that a body undergoing uniform acceleration is indistinguishable from one that is stationary in a gravitational field.

4. How we describe today? • Using General Theory of Relativity • The curvature of space-time determines the motion of inertial objects • The existence of gravitation is the consequence of the curvature of space-time.

5. “Daily” Gravitation • In our daily life, gravitation is most known as the agent that gives weight to objects. • Gravitation explains why objects fall down when they are dropped. • With existence of gravitation, we can walk and move on the ground.

6. However… Gravitation has a much vaster significance • Gravitation is responsible for the formation of Earth and other planets. • Gravitation also makes our planet revolve around the sun and the moon revolve around the earth. • For the Earth: • Gravitation keeps the water on the Earth, the inhabitants on Earth, and the Earth's atmosphere in its place.

7. Before “Gravity”… How gravity develop cannot be isolated from ASTRONOMY. To look at the history before the concept of “Gravitation” is intentioned, we must analyze from different perspectives: Culture influence, Religion Control, and lack of Knowledge

8. Are We the center of the Universe? Before Isaac Newton discovered gravity, people believed what the Catholic Church was teaching. The Catholic Church, as the most powerful influence in public and society, was teaching people that everything revolved around the Earth. God was the one who was using His power to hold up the heavenly bodies. • Why everything on the earth is falling down not lifting up? • That’s the Power of God!! • OMG!!You are kidding me?

9. The most prevailing view towards Astronomy & Gravity • Early scientists do find the phenomenon that Apple is falling down from the tree. Then, they started to create theory to explain it. • the geocentric theory: Earth was the center of the universe, dominated ancient and medieval science. It seemed evident to early astronomers that the rest of the universe moved about a stable, motionless Earth.

10. How does gravitation impact society • Most important impact to society is one of the key factors for life existing, more specifically, for us to live. • Inventions based on gravity • Eg: Gravia. • Gravia is a gravity based kinetic energy lamp created by Clay Moulton in 2007. The driving idea of Gravia is that light is generated when the user raises weights from the bottom to the top of the lamp.

11. Use as ENERGY • Gravia is an efficient, energy-saving invention. That means gravity can be use as an energy producer. This is another important impact on our society. It can be a new resource of energy.