Mitrisin History of Astronomy

Aristotle

322 BCE

384-322 BC

Aristotle studied under the great philosopher Plato and later started his own school, the Lyceum at Athens. He, too, believed in a geocentric Universe and that the planets and stars were perfect spheres though Earth itself was not. He further thought that the movements of the planets and stars must be circular since they were perfect. Today, we know that none of this is the case, but Aristotle was so respected that these wrong answers were taught for a very long time.

Ptolemy

168

100-168 AD

Ptolemy was an astronomer and mathematician. He believed that the Earth was the center of the Universe. The word for earth in Greek is geo, so we call this idea a "geocentric" theory. Even starting with this incorrect theory, he was able to combine what he saw of the stars' movements with mathematics, especially geometry, to predict the movements of the planets. His famous work was called the Almagesti.

Copernicus

1543

1473-1543 AD
Well over a thousand years later, Nicolaus Copernicus came up with a radical way of looking at the Universe. His heliocentric system put the Sun at the center of our system. He was not the first to have this theory. Earlier starwatchers had believed the same, but it was Copernicus who brought it to the world of the Renaissance and used his own observations of the movements of the planets to back up his idea.

Tycho Brahe

1601

1546-1601 AD
Tycho Brahe was a Danish nobleman, astronomer, and writer known for his accurate and comprehensive astronomical and planetary observations. Tycho believed that good astronomy relied on highly accurate observations. To that end, he designed, built, and constantly calibrated instruments. He used these instruments to make accurate and detailed measurements.

Hans Lippershey

1619

1570-1619 AD
Hans Lippershey was a Dutch eyeglass maker who many historians believe was the inventor of the first telescope. Lippershey settled in the Netherlands, opening a shop in Middleburg. One story relating to the development of the telescope involves Hans noticing two children playing with lenses in his shop. The children observed that when they looked through two lenses, and a weather vane appeared to be larger and clearer. He then placed a tube between the lenses to make a telescope.

Johannes Kelper

1630

1571-1630 AD
Johannes Kepler made the laws of planetary motion and some improvements to the telescope. He published his three laws of planetary motion. These laws describe how planets move around the Sun; (Law of Ellipses): Planets orbit the Sun in an elliptical orbit, (Law of Equal Areas): A line segment connecting a planet and the Sun will carve out equal areas in equal time, Third Law (Law of Harmonies): The period of a planet squared is proportional to the semi major axis of its orbit cubed.

Galileo

1642

1570-1642 AD
Galileo became a brilliant student with an amazing genius for invention and observation. He had his own ideas on how motion really worked, as opposed to what Aristotle had taught, and devised a telescope that could enlarge objects up to 20 times. He was able to use this telescope to prove the truth of the Copernican system of heliocentrism. He published his observations which went against the established teaching of the Church.

Difference between refracting and reflecting telescopes

1668

1668

The job of the objective lens is to gather the light coming from a distant object, such as a star, and bend it into a single point of focus.The eyepieces' job is to enlarge that focused image for our retina; it acts as a magnifying glass. A reflector telescope uses two mirrors instead of two lenses. Isaac Newton developed this telescope to combat chromatic aberration. Light from an object enters the telescope tube and is reflected off a curved mirror at the end of the tube.

Giovanni Cassini

1712

165-1712 AD
Astronomer Giovanni Cassini is associated with a number of scientific discoveries and projects, including the first observations of Saturn's moons. For this reason, the Cassini spacecraft that launched in 1997. Born on June 8, 1625, in Perinaldo, Republic of Genoa, he was given the name Giovanni Domenico by his parents, However he also used the name Gian Domenico Cassini, and after he moved to France as an adult, he changed his name to the French version Jean-Dominique Cassini.

Sir Isaac Newton

1724

1643-1724 AD
Before Newton, standard telescopes provided magnification, but with drawbacks. Known as refracting telescopes, they used glass lenses that changed the direction of different colors at different angles. This caused fuzzy or out-of-focus areas around objects being viewed through the telescope. After many tests, including grinding his own lenses, Newton found a solution. He replaced the refracting lenses with mirrored ones, including a large, concave mirror to show the primary image.

William Herschel

1822

1738-182 AD
On March 13, 1781, Herschel noticed a small object that, over the course of several nights, was slowly moving across the sky. At first he thought he had found a comet, but further observation revealed that the object was a planet. As a result of his discovery, the monarch knighted Herschel and appointed him to the position of court astronomer. The attached pension allowed him to conclude his musical career and focus his full attention on the skies.

Percival Lowell

1916

1855-1916 AD

Determined to be prepared in 1894, when the red planet drew closest to Earth. In search of the ideal place to study Mars, he selected Flagstaff, Arizona, where the high altitude, thin atmosphere and remote location would give him a good view of the planet. There, he built Lowell Observatory on Mars Hill, where he sketched the surface of Mars as it drew near. What he found electrified him. Soon after his observations, Lowell announced his discovery of canals and oases on Mars.

Karl Jansky

1950

1905-1950 AD
Karl graduated w/ a degree in physics, joined the staff of the Bell Labs, which wanted to investigate using "short waves" for transatlantic radio phone service. He built an antenna designed to receive radio waves at a frequency of 20.5 MHz. It was put on a turntable that allowed it to rotate in any direction. After recording signals from all directions for several months, Jansky identified 3 types of static: nearby and distant thunderstorms,and a faint steady hiss of unknown origin.

Edwin Hubble

1953

1889-1953 AD

In studying the various galaxies, Hubble was able to determine that they did not sit stationary in space. Instead, virtually every galaxy seems to be rushing away from Earth (the Andromeda Galaxy is instead rushing toward us and will collide with the Milky Way in about 5 billion years). Astronomers rushed to test his calculations on other galaxies, and found that some were moving as quickly as 90 million mph (40,000 kilometers per second) in the opposite direction.

Albert Einstein

1955

1879-1955 AD
Alberts equation that helped explain special relativity – E = mc2 – is famous even among those who don't understand the underlying physics. He also is known for his work on general relativity and the photoelectric effect; his work on the latter earned him a Nobel Prize in 1921. Einstein also made vain attempts to unify all the forces of the universe in a single theory, which he was still working on at the time of his death.

Sputnik

1957

1957 AD

Sputnik Chief Designer Sergei Korolyov watched as a modified Russian missile launched into space from Kazakhstan's lonely steppes carrying a very special payload. Sputnik 1 was about the size of a basketball and weighed about 180 pounds. It was equipped with two radio transmitters and four long antennas that broadcasted a constant beep while circling the Earth for 21 days. Sputnik's launch stunned the world and changed it, too. It heralded in dramatic fashion a new "space age."

Ejnar Hertzsprung

1967

1873-1967 AD
He had no formal education in astronomy but studied in technological colleges in Denmark and became a chemical engineer. Keenly interested in the chemistry of photography, he turned to astronomy in 1902, working in small Danish observatories, where he applied photography to the measurement of starlight. In two papers, published in 1905 and 1907, he showed that a relationship exists between the colours of the stars and their true brightness and that giant and dwarf stars must exist.

Yuri Gagarin

1968

1968 AD
Yuri Gagarin was the first person to fly in space. His flight, on April 12,1961, lasted 108 minutes as he circled the Earth for a little more than one orbit in the Soviet Union's spacecraft. Following the flight, Gagarin became a cultural hero in the Soviet Union. Even today, more than six decades after the historic flight, Gagarin is widely celebrated in Russian space museums, with numerous artifacts and statues displayed in his honor. His remains are buried at the Kremlin in Moscow.

The Apollo Program

1972

1963-1972
Apollo was the NASA program that resulted in American astronauts making a total of 11 space flights and walking on the moon. The first four flights tested the equipment used in the Apollo Program. Six of the other seven flights landed on the moon. The first Apollo flight happened in 1968. The last moon landing was in 1972. A total of 12 astronauts walked on the moon. The astronauts conducted scientific research there. They collected moon rocks to bring back to Earth.

First Space Shuttle Flight

1981

1981

Columbia was the first shuttle to reach space, in 1981. Columbia carried dozens of astronauts into space during the next two decades, reaching several milestones. Columbia also underwent upgrades as technology advanced. However, the shuttle and a seven-member crew were lost over Texas when Columbia burned up during re-entry on Feb. 1, 2003. Columbia's loss prompted NASA to do extra safety checks in orbit for all future missions.

Mars Pathfinder Expedition

1996

Mars Pathfinder was launched December 4, 1996 and landed on Mars' Ares Vallis on July 4, 1997. It was designed as a technology demonstration of a new way to deliver an instrumented lander and the first-ever robotic rover to the surface of the red planet. Pathfinder not only accomplished this goal but also returned an unprecedented amount of data and outlived its primary design life. Both the lander and the 23-pound (10.6 kilogram) rover carried instruments for scientific observations.

Cassini Orbiter

1997

1997

Cassini-Huygens was one of the most ambitious missions ever launched into space. Loaded with an array of powerful instruments and cameras, the spacecraft was capable of taking accurate measurements and detailed images in a variety of atmospheric conditions and light spectra. The spacecraft was launched with two elements: the Cassini orbiter and the Huygens probe. Cassini-Huygens reached Saturn and its moons in July 2004.

Neil Armstrong

2012

1930-2012
Neil Armstrong was a NASA astronaut most famous for being the first person to walk on the moon, on July 20, 1969. An accomplished test pilot, Armstrong also flew on the Gemini 8 mission in 1966. He retired from NASA in 1971 and remained active in the aerospace community, although he chose to keep mostly out of the public spotlight. Armstrong died Aug. 25, 2012, at age 82. Armstrong preferred to focus on the team that helped him get to the moon rather than his own first steps.

John Glenn

2016

1921-2016
John Glenn was part of the first group of astronauts NASA selected. In 1962, he became the first American to orbit Earth. After leaving NASA, he became a U.S. senator. Later, he became the oldest person to fly in space. In 1959, NASA selected its first group of astronauts, the “Mercury Seven.” In 1962, John Glenn became the first American astronaut to orbit Earth. Two cosmonauts from the former Soviet Union already had orbited Earth, including Yuri Gagarin, the first man in space.

A lunar rock sample found by Apollo 14 astronauts

2019

1971-2019
In 1971, astronauts aboard the Apollo 14 mission collected a Moon rock that scientists have now found likely originated on Earth. During a new investigation, researchers found that the rock, officially named 14321, contains traces of minerals and has a chemical makeup that are both common to Earth and extremely strange for the Moon. The research team thinks that, most likely, a rock that formed on Earth four billion years ago was launched to the Moon’s surface by an asteroid impact.