The Sun: Man's Friend & Foe

circa 384-322 B.C.	Aristotle developes the geocentric theory.

circa 408-355 B.C.	Eudoxus of Cnidus became the first mathematician to give a theoretical explanation of celestial movement. He supported Aristotle's heliocentric views.

129 B.C.	Hipparchus records solar eclipse. He later used the information he gained from this experience to determine the distance between the Earth and moon.

773	Numerical tables from India introduced to western culture. They were used for calendar and astrological purposes and were important because they introduced the Indian system of numerals (with place-value and zero for open place). These numerals were later called arabic numerals.

1543	Copernicus developes the heliocentric theory.

1610	Galileo and Johann Goldsmid discover sunspots.

1604	Zacharias Janssen, optician, constructed more advanced telescope.

1609	Johannes Kepler - Laws 1 & 2

1610	Galileo publishes Sidereus Nuncius (Messenger of the Stars), his first published work supporting the Copernicus theory.

1618	Johannes Kepler - Law 3

1676	Olaf Romer calculates speed of light.

1687	Issac Newton - Principia

1690	Christian Huygenus discovers polarized light

1752	Benjamin Franklin does lightning experiments.

1782	William Herschel publishes his first star catalog and his discoveries on the motion of the Sun.

1795	William Herschel publishes his views on the nature of the Sun.

1800	William Herschel discovers infrared rays in the solar spectrum.

1814	Joseph Fraunhofer develops Fraunhofer lines.

1816	Photography invented.

1843	Schwabe discovers the frequency of appearance of sunspots and how they appear in cycles.

1845	First photograph of the Sun taken.

1852	Rudolph Wolf discovers that the sunspot cycle is 11 years long.

1860	Bunsen and Kirchhoff discover spectral analysis.

1864	James Maxwell develops Maxwell's equations.

1868	Helium is discovered in the spectrum of the solar chromosphere.

1870	Lane publishes his theory on the Sun's temperature.

1897	Joseph Thomson discovers electrons.

1898	Swedish scientist Svante Ahrrenius warns that Industrial Revolution's carbon dioxide emissions, could accumulate in atmosphere and lead to global warming.

1905	Einstein published his paper "On the electrodynamics of moving bodies", The Theory of Special Relativity.

1908	Hale discovers the magnetic fields of sunspots.

1917	Einstein develops a static universe model.

1918	Shapley discovers the galactic hallow.

1926	Eddington publishes "The Internal Constitution of the Stars"

1947	The transistor is invented.

1959	Sputnik launched.

1961	New observatory atop Hawaii's Mauna Loa volcano detects rise in atmospheric carbon dioxide.

1969	Apollo moon landing.

1972	Skylab launched into orbit.

1980s	Computer models of world climate project temperature rises.

1985	Skylab II launched into orbit.

	U.N. establishes authoritative network of climate scientists, Intergovernmental Panel on Climate Change.

1990	IPCC certifies scientific basis for "greenhouse effect" and global warming predictions.

1991	Yohkoh launched into orbit.

1992	Climate change treaty signed, setting voluntary goals for industrial nations to lower greenhouse gas emissions to 1990 levels by 2000.