Astronomy terms starting with O

4 terms

1. Observed Brightness The flux due to a light emitting object measured at the observer (in most cases, at the earth or a satellite).
2. Omega, Ω The ratio of the average total density of matter to the critical density required to make the universe flat and eventually stop its expansion.
3. Opaque to Radiation A condition when radiation is absorbed or scattered many times. For the first 400,000 years the universe was so hot that the matter was ionized and…
4. Open Universe , Ω A universe where the geometry of space is curved like an infinite saddle-shaped surface.