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Gravity Probe B

Testing Einstein's Universe

Examples of Great Discoveries in the Fundamental Forces:

Four fundamental forces govern our universe: electromagnetism, the strong and the weak nuclear forces, and gravity. Einstein himself (unsuccessfully) spent a great portion of his life trying to relate these forces and unify their laws into one set of governing equations that would apply to all.


Arguably the most practical area of scientific discovery in the last 200 years has been electromagnetism. For a long time no one knew for certain how magnetism and electricity were related. No one understood the electromagnetic nature of light or the propagation of electromagnetic waves in general (such as radio waves, microwaves or X-rays).
As you may recall, Benjamin Franklin investigated electromagnetic energy in the form of lightning. No one knew what lightning really was (except perhaps that it was something to be avoided whenever possible). Many people thought Ben Franklin was crazy, or that he would probably kill himself. However, he discovered that lightning was actually related to other electrical phenomena (something long suspected by the scientific community, but never proven until Franklin's experiment), and in 1752 Franklin invented the lightning rod. The most evident lesson of Franklin's work is that understanding more about lightning enabled us to redirect strikes and ultimately save lives. For more information, see "The Key & the Kite Experiment" web page.

Far reaching discoveries were made by James Clerk Maxwell in the late 1800s. His theories and discoveries definitively and conclusively explain the relationship between electricity and magnetism, and also tell us how light is propagated. Because these relationships were verified and the phenomena of light explained, we can wirelessly transmit electromagnetic signals. Thanks to his discoveries and the inventors who furthered them, we can watch TV, listen to the radio, use a microwave oven, transmit signals through space from satellites and generate electricity. However, when Maxwell was first studying electromagnetism, people weren't visualizing ahead to the day when we could each have our own light bulbs and computers - and they certainly weren't thinking of satellite TV or rental-car GPS units.

In 1888, fifteen years after Maxwell had published his work, Professor Heinrich Hertz demonstrated Maxwell's theories by successfully sending a spark from a transmitter in one corner of the room to a receiver in the opposite corner without the use of wire or any physical connection. He was asked by a student if these electromagnetic waves could be of any practical use. Hertz answered "None whatsoever. It's simply an interesting laboratory experiment which proves that Maxwell was right. I don't see any useful purpose for this mysterious, invisible electromagnetic energy." Clearly, the Dr. Hertz was not a prophet.

Nuclear Forces

Fusion & Fission: Based on research in Special Relativity, mankind learned how to harness energy from the elements. Remember Einstein's E=mc2? It was used to learn how to release the energy in the heavy elements (fission) and how to create more energy by fusing light elements together. This technology was first used to create atomic bombs (a controversial choice and one that Einstein was remorseful about), and later nuclear energy plants -also controversial. If we continue our research efforts, we will, hopefully, one day be able to safely provide huge amounts of energy with harmless helium as a by-product. For better or for worse, nuclear weaponry has completely changed the global political dynamic.

Quantum Mechanics:

Due to basic research at linear accelerators and subsequent advances in quantum mechanics, the MRI and the tunneling electron microscope were invented. Magnetic Resonance Imaging is used in medical scanning equipment and has saved many people exploratory brain surgery. The scanning tunneling electron microscope allows us to understand materials at new levels, thus enabling advances in computer technology and aviation, among other things.


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