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gamma rays - the region of energy in the electromagnetic spectrum from about 10-5 to 10-1 nm in wavelength; smallest wavelengths and the most energy of any wave in the electromagnetic spectrum. (more)

global climate change - the hypothesis that the known increase in greenhouse gas concentrations has led and will continue to lead to changes in the Earth's climate; also known as "global warming."

gravitational force - force exerted by a body as a result of its mass.

greenhouse effect - the process of incoming short-wave solar radiation being absorbed by the surface of the Earth and re-emitted as longer-wavelength radiation, which is then absorbed, retained, and re-radiated by certain gases in the atmosphere. The net result is a "warm blanket" around the Earth that prevents sudden cooling and heating effects each time the face of the Earth rotates away from or towards the sun. (more)

greenhouse gases - gases in the atmosphere which absorb, retain, and re-radiate energy in the infrared region. (more)

  ©Copyright 2003 Carnegie Mellon University
This material is based upon work supported by the National Science Foundation under Grant Number 9653194. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.