Astrophysics terms starting with S

17 terms

  1. Scalar A constant number. 1, -16, .3534, 7346 are all scalars.
  2. Scatter When refering to photons and light, scattering describes the phenomenon of a source absorbing, and then emanating light in all directions.
  3. Sensitivity When referring to a medical test, sensitivity refers to the percentage of people who test positive for a specific disease among a group of people who have…
  4. Simultaneous Occurring at the same time.
  5. Spacetime The theory of relativity says that time cannot be treated absolutely separately from space, only in one observer's relative view.
  6. Spectra A range of different measurements. In terms of physics, spectra usually refers to the different wavelengths, or colors (if in the visible range) of light…
  7. Spectral Line An emission (bright) or absorption (dark) of light at a specific frequency or wavelength.
  8. Standard Candle A celestial object whose intrinsic brightness is known or can be estimated by some physical principle.
  9. Static Unchanging over a length of time.
  10. Steady State Theory A cosmological model where matter is created constantly as the universe expands so it remains homogenous and isotropic.
  11. Stochastic Random.
  12. Strong Force The interaction responsible for binding quarks, antiquarks, and gluons to make hadrons. Residual strong interactions provide the nuclear binding force.
  13. Structure Changes in the shape of the bottom of lakes, rivers, or impoundments, especially those that influence fish behavior.
  14. Super Cluster A cluster of clusters of galaxies. A vast collection of galaxy clusters that may contain tens of thousands of galaxies spanning over a hundred million…
  15. Supernova Supernova refers to several types of stellar (meaning star) explosions that produce extremely bright objects that decline to invisibility over weeks or…
  16. Synthesis of Nuclei Combining protons and neutrons to form nuclei.
  17. Systematic Errors Measurement errors that are not random.