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- Occam's Razor
- a way of approaching the development of a scientific
model based on the belief that ``the best model is the simplest one---the one
requiring the fewest assumptions and modifications in order to fit the observations''
(i.e., nature prefers the simplest most elegant solution).
- the primary optical element of a telescope, it gathers the
electromagnetic radiation and does the initial focussing.
- Olbers' Paradox
- the problem that if the universe is
infinite in size and age, then the night sky should everywhere be as bright
as the Sun because no matter which direction you look, your line of sight
will see a star or galaxy.
- Oort Cloud
- a large spherical cloud of billions to trillions
of comets surrounding the Sun at distances between roughly 50,000 to
100,000 A.U. from the Sun. It has not been
directly observed; its presence
is inferred from the behavior and orbits of the long period comets.
- a measure of a material's ability to absorb or
block photons. A material with high opacity prevents most of the
photons from passing through (the material is opaque).
- open universe
- a universe with too little matter (gravity)
to stop the expansion (it has an ``open future'').
- a type of oxygen molecule made of three oxygen atoms bound
together (O3). This molecule absorbs ultraviolet light.
Glossary links (select a letter for definitions of astronomy terms
beginning with that letter):
A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z
last updated: 27 May 2001
Is this page a copy of Strobel's
Author of original content: