Search results
Results from the WOW.Com Content Network
A. E. (Andrew Ellicott) Douglass (July 5, 1867 in Windsor, Vermont – March 20, 1962 in Tucson, Arizona) was an American astronomer. He discovered a correlation between tree rings and the sunspot cycle , and founded the discipline of dendrochronology , which is a method of dating wood by analyzing the growth ring pattern.
Alternation of generations – Beta oxidation – Bioelectricity – Biological pest control – Biological rhythm – Bipolar disorder – Cardiopulmonary resuscitation – Calvin–Benson cycle – Cell cycle – Chronobiology – Citric acid cycle – Circadian rhythm – Clinical depression – Digestion – Ecology – Feedback – Infradian rhythm - Life cycle – List of biochemistry ...
Andrew Ellicott (January 24, 1754 – August 28, 1820) was an American land surveyor who helped map many of the territories west of the Appalachians, surveyed the boundaries of the District of Columbia, continued and completed Pierre (Peter) Charles L'Enfant's work on the plan for Washington, D.C., and served as a teacher in survey methods for Meriwether Lewis.
Representative lifetimes of stars as a function of their masses The change in size with time of a Sun-like star Artist's depiction of the life cycle of a Sun-like star, starting as a main-sequence star at lower left then expanding through the subgiant and giant phases, until its outer envelope is expelled to form a planetary nebula at upper right Chart of stellar evolution
In 1788, George Ellicott, a son of Andrew Ellicott, loaned Banneker books and equipment to begin a more formal study of astronomy. [30] [31] [32] During the following year, Banneker sent George his work calculating a solar eclipse. [30] [31] [29] In 1790, Banneker prepared an ephemeris for 1791, which he hoped would be placed within a published ...
A cyclic model (or oscillating model) is any of several cosmological models in which the universe follows infinite, or indefinite, self-sustaining cycles. For example, the oscillating universe theory briefly considered by Albert Einstein in 1930 theorized a universe following an eternal series of oscillations, each beginning with a Big Bang and ending with a Big Crunch; in the interim, the ...
The pattern of seven-day weeks repeats over a two-year cycle, i.e., the calendar year always begins on a Sunday in odd-numbered years, thus effecting a perpetual calendar for Mars. [27] Whereas previous proposals for a Martian calendar had not included an epoch, American astronomer I. M. Levitt developed a more complete system in 1954.
The anthropic principle, also known as the observation selection effect, is the proposition that the range of possible observations that could be made about the universe is limited by the fact that observations are only possible in the type of universe that is capable of developing intelligent life.