Astronomy terms starting with I

17 terms

  1. Inflation A condition of increasing prices. Inflation is generally measured by the Consumer Price Index.
  2. Infrared The range of invisible radiation wavelengths from about 700 nm, just longer than red in the visible spectrum, to 1 mm, on the border of the microwave…
  3. Infrared (IR) Radiation Infrared (IR) radiation is electromagnetic radiation whose wavelength is longer than that of visible light, but shorter than microwaves.
  4. Inhomogeneity Something not evenly distributed in space; a clump or cluster.
  5. Initial Being first, before anything else occurs.
  6. Initial Conditions The nature of a system's state when time equals zero.
  7. Intensity With regards to light, intensity is the energy moving through a region of area per unit of time.
  8. Intrinsic Luminosity A measure of the true brightness of an object. It is the amount of energy radiated into space every second by a celestial object, such as a star.
  9. Inverse Square 1 divided by a quantity squared. 1/(r^2). The force due to gravity is proportional to 1 over distance squared. F~1/(d2).
  10. Ion An atom or molecule that has lost or gained one or more electrons and has become electrically charged as a result.
  11. Ion, Ionize An ion is an atom which has lost or gained one or more electrons so that it has a net electrical charge.
  12. Ionization A process that produces ions, typically collisions between atoms or electrons, or by interaction with electromagnetic radiation.
  13. Ionized The state in which an atom is missing on or more of its electrons, and is therefore positively charged.
  14. Ionosphere The region of Earth's atmosphere that extends from about 50 to 300 miles above the surface of the planet and is made up of multiple layers dominated by…
  15. irradiation (ih-RAY-dee-AY-shun) The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors.
  16. Isotopes atoms that have the same number of protons, but a different number of neutrons are isotopes of each other.
  17. Isotropic the property of being independent of direction. Isotropic radiation has the same intensity regardless of the direction of measurement.