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Galileo begins experiments with falling and rolling bodies.
Galileo's experiments led him to conclude that once something is set in motion it will remain in motion unless something stops it. This contradicted earlier ideas that said only rest was a natural state. -
Period: to
Last 400 Years
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Galileo uses telescope for astronomical observations
Galileo uses telescope for astronomical observations. Galileo didn't invent the telescope but he was among the first to use a telescope to examine the heavens. He carried out important observations of the Sun, Moon, Planets, and Stars. -
Galileo publishes "The Dialogue".
The Dialogue, although superficially a balanced debate about the merits of the geocentric and heliocentric models of the solar system, was in fact a powerful argument for the ideas of Copernicus. Galileo was brought before the Inquisition and spent the last nine years of his life under house arrest. -
Newton discovers law of universal gravitation.
When Cambridge University was closed by the plague, Newton spent most of the next two years at his family farm. During this period he made fundamental discoveries in optics, discovered the law of universal gravitation, and invented differential and integral calculus. -
Meteorite shower at l'Aigle convinces scientists that meteorites have an extraterrestrial origin
A careful investigation of the shower by Edouard Biot convinced most skeptics that meteorites really do fall from the sky. -
Albert Einstein explains the photoelectric efect.
Einstein explained that the emission of electrons only by light at short wavelengths occurs because light consistes of bundles of energy called photons. -
Albert Einstein's general theory of relativity.
Einstein explained that matter curves space, causing bodies to move in ways we attribute to gravity. -
Edwin Hubble discovers universe is expanding.
Hubble found that the speed of recession of galaxies increases with distance. He explained that this is due to the expansion of the universe. -
Fleet of space probes encounters Comet Halley.
A fleet of five space probes flew past Comet Halley at distances as small as 600 km. Images sent back by the spacecraft showed that the nucleus of Halley is very dark and larger than anticipated. -
Hubble Space telescope launched.
Hubble Space telescope launched.