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The Idea of the Telescope Comes About
The national government discussed the idea of a device that aided people in seeing faraway things as though they are nearby. -
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Kepler Configures the 3 Laws of Planetary Motion
- The path of the planets about the sun is elliptical in shape, with the center of the sun being located at one focus. (The Law of Ellipses)
- An imaginary line drawn from the center of the sun to the center of the planet will sweep out equal areas in equal intervals of time. (The Law of Equal Areas)
- The ratio of the squares of the periods of any two planets is equal to the ratio of the cubes of their average distances from the sun. (The Law of Harmonies)
- The path of the planets about the sun is elliptical in shape, with the center of the sun being located at one focus. (The Law of Ellipses)
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Galileo Discovers a Modern View of the Heavens
A view of the heavens started in the early 1600's when Galileo first turned his newly invented telescope to the heavens and saw worlds in their own right. -
Saturn's Rings Discovered
Christiaan Huygens realizes that the "appendages" of Saturn are rings. He realized that the appendages were really flat rings that disappeared when viewed edge on. -
Distance of the Stars Calculated
James Gregory makes the first realistic estimate of the distances of the stars. Gregory assumed that the other stars were just as bright as the Sun and then calculated how distant they had to be to match their apparent brightnesses. -
Stars Move?
Edmund Halley discovers stars move through space. He found that the positions of stars change with time and explained the changes in position as due to the individual motions of stars through space -
Aberration of Starlight Discovered
James Bradley discovers the aberration of starlight. He found that the positions of all the stars shift back and forth as part of an annual cycle caused by the motion of the Earth about the Sun. -
Uranus Discovered
William Herschel discovers Uranus. While measuring the directions and brightnesses of stars, Herschel found a fuzzy spot that moved among the stars. This was Uranus, the first planet that was not known to the ancients. -
Milky Way is Mapped
William Herschel uses star counts to map Milky Way. Herschel assumed that the galaxy extended farther in directions in which he could see more stars. He found the galaxy to be flattened with the Sun near the middle. -
Black Holes Discovered
Pierre Simon Laplace proposes stars can produce black holes. Laplace proposed that if a star is so compact that its escape velocity exceeds the speed of light, then not even light can escape from the star. -
Asteriods are Discovered
Giuseppe Piazzi discovered Ceres, the first known asteroid, on January 1, 1801, the first day of the 19th century. -
Neptune is Found
John Couch Adams and Urbain Le Leverrier discover Neptune. Adams and Leverrier independently calculated the location of the unknown planet, Neptune, that was required to explain discrepancies in the orbit of Uranus. -
The Earth Rotates
Jean Foucault uses a pendulum to demonstrate Earth rotates. -
Life on Mars?
Giovanni Schiaparelli discovers "canals" of Mars. Schiaparelli reported thin, dark lines crisscrossing the surface of Mars, which raised the possibility of intelligent life on Mars. -
Pluto Found
The planet Pluto is discovered. -
The First Radio Telescopse Was Invented
The inventor of the radio telescope is Grote Reber. In 1937 in his backyard he built the world's first radio telescope. The dish was 31 feet across and the telescope could move both the dish and the mount. -
U.S. Launches Explorer 1
The United States launched its first Earth satellite on January 31, 1958. -
SETI has Begun
SETI is an acronym for the Search for Extraterrestrial Intelligence. It is the science of using telescopes, radio and optical, to search the skies for signals from alien civilizations. -
The World's First SETI Meeting
The world's first SETI meeting was convened at Green Bank by Drake in 1961. As the agenda for that conference, Drake drafted an equation for estimating the number of possible communicative technologies in the cosmos. -
The Drake Equation
The Drake Equation was developed by Frank Drake in 1961 as a way to focus on the factors which determine how many intelligent, communicating civilizations there are in our galaxy. -
Kennedy Challenges the Nation
In President Kennedy's speech to Congress, on May 25, 1961, he expressed a concern that the United States was falling behind the Soviet Union in technology and prestige. He challenged the nation to put a man on the moon before the end of the decade. -
Moon Landing
"That's one small step for a man, one giant leap for mankind."
Neil Armstrong became the first man on the moon. -
The Hubble Telescope
The Hubble Space Telescope's launch in 1990 sped humanity to one of its greatest advances in that journey. -
How Old is the Universe?
New measurements show that the Universe is 13.7 billion years old. -
Pluto No Longer a Planet
Pluto no longer has the status as a planet, now it is a Kuiper belt object.
