past+calculation
71Numerical model of the Solar System — A numerical model of the Solar System is a set of mathematical equations, which, when solved, give the approximate positions of the planets as a function of time. Attempts to create such a model established the more general field of celestial… …
72Timeline of Islamic science and engineering — This timeline of Islamic science and engineering covers the general development of science and technology in the Islamic world during the Islamic Golden Age, usually dated from the 7th to 16th centuries.From the 17th century onwards, the advances …
73radioactivity — /ray dee oh ak tiv i tee/, n. Physics, Chem. the phenomenon, exhibited by and being a property of certain elements, of spontaneously emitting radiation resulting from changes in the nuclei of atoms of the element. Also called activity. [1895… …
74General Chronology — General Chronology † Catholic Encyclopedia ► General Chronology Chronology (Greek chronos time, logos, discourse), the science of time measurement, has two branches: ♦ Mathematical Chronology, which determines the units to be… …
75Gregorian calendar — For the calendar of religious holidays and periods, see Liturgical year. For this year s Gregorian calendar, see Common year starting on Saturday. 2011 in other calendars Gregorian calendar 2011 MMXI …
76Gini coefficient — The Gini coefficient is a measure of statistical dispersion most prominently used as a measure of inequality of income distribution or inequality of wealth distribution. It is defined as a ratio with values between 0 and 1: A low Gini coefficient …
77Social Security (United States) — This article is about the retirement/disability program. For the general concept of providing welfare, see Social security. For other uses, see Social Security (disambiguation) …
78Carbon tax — Part of a series on Green economics Concepts …
79Carbon-14 — Infobox isotope background = #999999 isotope name = Carbon 14 num neutrons = 8 num protons = 6 isotope filename = alternate names = radiocarbon mass number=14 abundance = 1 part per trillion symbol=C decay product = 14N halflife=5,730 error… …
80Council Tax — Taxation An aspect of fiscal policy …
