Microgravity >> Fundamental Physics

Fundamental physics is the study of the basic laws that govern the properties of the physical world on all scales, from microscopic to cosmic. The discipline of fundamental physics continues to evolve as new technology and techniques improve and broaden the scope of scientific principles that can be experimentally investigated. The study of fundamental physics in the microgravity environment can yield entirely new or substantially improved results when the obscuring effects of Earth's gravity are not present. Researchers will use the microgravity environment to test some of the most fundamental theories of physics, such as Einstein's theory of general relativity and Newton's laws concerning gravitation.

Until recently, the work of microgravity fundamental physics focused primarily on condensed matter physics at extremely low temperatures, with a particular emphasis on investigations of liquid helium. Scientists have observed that at these extremely low temperatures, sometimes close to absolute zero (-273° C), some materials, like helium, will experience unusual phase transitions to states of matter that cannot be simply classified as gas, liquid, or solid. These states include superfluidity, in which a fluid flows without friction and has a very high thermal conductivity, and superconductivity, in which a material conducts electricity or heat with no resistance or loss of energy. Superconductors are used to make high-strength, lower-power magnets for medical applications (such as magnetic resonance imaging, or MRI) as well as high-precision thermometers. Superconductors can also be used for magnetic shielding and may soon be applied in the power and transportation industries.

Another area of research in microgravity fundamental physics, and one which is relatively new, is laser cooling and atomic physics. Researchers working in this area are interested in the study of the structure of isolated atoms and their interactions with external stimuli, such as other atoms, surfaces, electromagnetic fields, temperature, pressure, and light. Laser cooling technology provides a new method of investigation in which atoms are bombarded with light to slow their movement, allowing scientists a longer time to observe them. Microgravity will improve this technology by eliminating the external stimulus of gravity, which affects the motions of atoms.

Fundamental physics research will also play a significant role in the human exploration and development of space. Engineers have already designed atomic clocks, which use laser-cooled atoms to maintain high-precision time standards. These clocks can be used to help spacecraft maintain accurate courses over vast distances and to help aircraft make more precise landings in situations that require automatic landing systems, such as in inclement weather or when visibility is limited.

Text source: Hampton University/NASAl