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What Is Constant Physics?

In constant physics, scientists investigate the fundamental physical constants of nature. Almost without exception, fundamental physical constants are the same everywhere in the universe and are expressed by a value (number) and symbolized by a letter of the alphabet, sometimes a Greek letter. Well-known constants include the mass of a proton and the speed of light. A lesser-known one is the fine-structure constant.

Importance
- Fundamental physical constants apply to time, matter, space and energy and are tools in aiding scientists "to understand and predict the past, present and future of the universe," states astro-physicist Neil deGrasse Tyson in an article in the November 2004 issue of "Natural History."
Standardization
- The work of physicists, cosmologists, astronomers and other scientists who use fundamental physical constants requires precision and uniformity. The Committee on Data for Science and Technology is the international organization established to ensure that the fundamental physical constants use the same values and conversion factors worldwide. Founded in 1966, CODATA issued its most recent set of fundamental physical constants in 2010. The National Institute of Standards and Technology (an agency of the United States Department of Commerce) is the domestic counterpart of CODATA.
Modifications
- Regardless of the word "constant," the values of these constants do sometimes change based on scientific experiments. For example, in 2010 the value of the fine-structure constant -- symbolized by alpha, the first letter of the Greek alphabet -- changed from its 2006 value. Because of improved measuring techniques and the correction of an error in the presentation of the theory governing alpha, its 2010 value is more accurate. In fact, NIST said the uncertainty in its 2010 value had been cut in half to 0.3 parts per billion.
Fine-Structure Constant
- The fine-structure constant, or alpha, measures the strength of electromagnetic forces. It is particularly relevant to the relationship between atoms and light absorption. Alpha is a dimensionless number, meaning its value is the same no matter whether scientists use the metric, U.S., imperial or other measuring system. The value of alpha is about 1/137.03599.
  
  In a study released in 2010, scientists studying quasars using two telescopes, one in Chile and the other in Hawaii aimed in opposite directions, found the value of alpha was different depending on which direction they looked. So, perhaps alpha changes depending on its location.

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