The Solar Wind

 

The solar wind travels at a minimum speed of 500 KM per second towards earth and the entire solar system, but which force of the earth protects us from such an onslaught from solar wind and other high-energy particles of the sun? Obviously, gravity cannot perform this critical task because it is a force of attraction. Then, which other force performs this crucial role of resistance?  

 

Newton’s Reservation on Gravity

(Reference from: http://en2.wikipedia.org/wiki/Gravity)

 

Newton's Reservations: It's important to understand that while Newton was able to formulate his law of gravity in his monumental work, he was not comfortable with it because he never, in his words, "assigned the cause of this power." In all other cases, he used the phenomenon of motion to explain the origin of various forces acting on bodies, but in the case of gravity, he was unable to experimentally identify the motion that produces the force of gravity. Moreover, he refused to even offer a hypothesis as to the cause of this force on grounds that to do so was contrary to sound science.

 

Quantum Mechanics and Waves: Gravity is the only one of the four fundamental forces of nature that stubbornly refuses to be quantised (the other three: Electromagnetism, the Strong Force, and the Weak Force, can be quantised). Quantisation means that the force is measured in discrete steps that cannot be reduced in size, no matter what; alternatively, that gravitational interaction is transmitted by particles called gravitons. Scientists have theorized about the graviton for years, but have been frustrated in their attempts to find a consistent quantum theory for it. Many believe that string theory holds a great deal of promise to unify general relativity and quantum mechanics, but this promise is yet to be realized.

 

It is true that Einstein's hypotheses are successful in explaining the effects of gravitational forces more precisely than Newton's in certain cases, but he too never 'assigned the cause of this power,' in his theories. It is said that in Einstein's equations, 'matter tells space how to curve, and space tells matter how to move,' but this new idea, completely foreign to the world of Newton, does not enable Einstein to assign the 'cause of this power' to curve space anymore than the Law of Universal Gravitation enabled Newton to assign its cause.

 

Speed of gravity: Einstein's theory of relativity predicts that the speed of gravity (defined as the speed at which changes in location of a mass are propagated to other masses) should be consistent with the speed of light. In 2002, the Fomalont-Kopeikin experiment produced measurements of the speed of gravity, which matched this prediction. However, this experiment has not yet been widely peer-reviewed, and is facing criticism from those who claim that Fomalont-Kopeikin did nothing more than measure the speed of light in a convoluted manner