Timeline of Earth Astronomy

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One complete wobble of the planet takes about 25,800 years.
    (NH, 5/96, p.67)
The Earth is 7,930 miles in diameter.
    (SFC, 8/7/96, p.A9)
If the Sun were a pumpkin one foot in diameter, Earth would be a pea about 100 feet away.
    (SFEC, 4/30/00, Par p.9)
A measurement of the Earth’s weight in 2000 set it at 5,972 sextillion tons, or 5,972 plus 18 zeroes.
    (SFC, 5/1/00, p.A6)
    5,130 Feet = Earth’s deepest known cave (2004) is the Krubera Cave in Abkhazia.
    (SFC, 8/17/04, p.A6)

The Web page of NASA’s Observatorium is:
The Web page for Earth Viewer is:
    (Nat. Hist. 3/96, p.11)

4.5Bil BC    Our moon formed when an iron-rich, Mars-sized planet or asteroid plowed into Earth while it was forming. Much of the iron ended up in the Earth’s core, whereas the cloud of dust ejected from the impact consolidated into the moon.
    (PacDis, Winter ’97, p.28)(Econ, 2/21/09, p.81)

190BCE    Hipparchus was born in what is now Turkey. He calculated the length of a year to within 6 1/2 minutes and was the first to explain the Earth's rotation on its axis. He also compiled the first comprehensive catalog of the stars. [see 160-125BCE]
    (LAT, 3/30/05)

160-125BCE    Hipparchus, Greek mathematician and astronomer, often called the father of modern astronomy. He attempted to calculate the distance to the moon and the sun. His estimate for the distance to the moon was 67r vs. the modern value of 60.267r. He estimated the sun to be 37 times farther than the moon and at least 12 times greater in diameter than the Earth. His figures were accepted for 17 centuries until the invention of the telescope and precise astronomical instruments. Together with Ptolemy he graded the visible stars into six magnitudes. The first magnitude was comprised of about 20 of the brightest stars. He compiled a stellar catalogue in Alexandria which shows the position of 1080 stars. [see 190BCE]
    (SCTS, p.7-8,137,142)

90-168CE    Claudius Ptolemy, geographer and mapmaker. He collected information from travelers and constructed maps of the then known world. His maps were forgotten as the Roman Empire declined and were not rediscovered until the early 1400s. Robert Newton in his book "The Crime of Claudius Ptolemy" (1977), called him "the most successful fraud in the history of science."
    (ATC, p.15)(NH, 6/97, p.43)(LAT, 3/30/05)

128CE        The Almagest by Ptolemy, roughly translated as "the Greatest Compilation," was published around this time and became one of the most influential scientific texts in history.
    (LAT, 3/30/05)

150CE        Ptolemy of Alexandria published his theory of epicycles, the idea that the moon, the sun and the planets moved in circles which were moving in circles which were moving in circles around the Earth.
    (Econ, 2/7/04, p.75)

1150        Adelard of Bath (b.1080), Englishman, died. He had traveled widely and translated the Arabic version of Euclid's "Elements" into Latin as well as several Arabic books on astronomy.
    (SSFC, 2/8/04, p.M2)

1400-1850    This was a frigid period in Europe and came to be called the Little Ice Age.
    (NG, 7/04, p.28)

1436        Jun 6, Regiomontanus (Johannes Muller), prepared astronomical tables, was born.
    (MC, 6/6/02)

1501        Jul 27, Copernicus was formally installed as canon of Frauenberg Cathedral.
    (MC, 7/27/02)

1506        Copernicus (1473-1543), Polish-born astronomer, was appointed canon of church properties in the Prussian diocese of Ermland.
    (ON, 2/11, p.5)

1512        Copernicus, Polish-born astronomer, wrote his manuscript “The Little Commentary,” in which he suggested that the earth’s apparent immobility was due to a “false appearance” and a sun-centered cosmos would resolve many astronomical inconsistencies.
    (ON, 2/11, p.5)

1539        German scholar George Joachim Rheticus received permission to write a condensed version of the ideas of astronomer Nicholas Copernicus. The short book was titled “First Account.”
    (ON, 2/11, p.6)

1543        May 24, Nicolaus Copernicus, astronomer, died in Poland. His book, "On the Revolutions of the Heavenly Orbs," (De Revolutionibus Orbium Caelestium), proof of a sun-centered universe, was printed just before he died. Although he did say that the earth rotated once a day and did revolve around the sun once a year, he kept 2 features of the old Aristotelian system: one involved uniform circular motion, and the other was quintessential matter, for which such motion was said to be natural. In 1916 the Catholic clergy placed the book on its “Index of Prohibited Books.” In 2004 Owen Gingerich authored "The Book Nobody Read," an examination of how the ideas of Copernicus spread. In 2006 William T. Vollmann authored “Uncentering the Earth: Copernicus and The Revolutions of the Heavenly Spheres.” In 2008 his remains, buried in a Roman Catholic Cathedral in Frombork, Poland, were positively identified using DNA evidence.
     (NG, 3/1990, p. 117)(WSJ, 3/5/04, p.W8)(NH, 4/1/04, p.66)(SSFC, 2/5/06, p.M1)(AP, 11/20/08)

1555        May 25, Gemma Frisius (46), Frisian geographer, astronomer, died.
    (SC, 5/25/02)

1560        Aug 21, Tycho Brahe (1546-1601) became interested in astronomy.
    (SC, 8/21/02)

1575        Jul 25, Christoph Scheiner, astronomer, was born in Germany.
    (SC, 7/25/02)

1595        Jul 9, Johannes Kepler inscribed a geometric solid construction of universe.
    (MC, 7/9/02)

1595        Aug 24, Thomas Digges, English astronomer (Universe Infinite), died.
    (MC, 8/24/02)

1611        Apr 14, Word "telescope" was 1st used by Prince Federico Cesi.
    (MC, 4/14/02)

1616        Mar 5, The Catholic Church’s Congregation of the Index banned Catholics from reading “On the Revolution of the Heavenly Spheres” (1543) by Nicholas Copernicus. “De Revolutionibus” was not formally banned but merely withdrawn from circulation, pending "corrections." The prohibition was officially lifted in 1835.

1616        Galileo was forbidden from continuing his scientific work by the Roman Catholic Church.
    (NG, March 1990, p. 117)

1618        Mar 8, Johannes Kepler came up with his Third Law of Planetary Motion.
    (SFC, 6/16/96, PM p.5)(HN, 3/8/98)

1618        May 15, Johannes Kepler discovered his harmonics law.
    (HN, 5/15/98)

1620        Jul 21, Jean Picard, French astronomer, was born.
    (MC, 7/21/02)

1620        Aug 7, Kepler's mother was arrested for witchcraft.
    (MC, 8/7/02)

1629        Apr 14, Christian Huygens (d.1695), Dutch astronomer, discoverer of Saturn's rings, was born. He invented the pendulum and along with Newton showed that any body revolving around a center is actually accelerating constantly toward that center, even though the rate of rotation remains constant.
    (TNG, Klein, p.30)(HN, 4/14/99)

1633        Jun 22, Galileo Galilei was again forced by the Pope to recant that the Earth orbits the Sun. On Oct 31, 1992, the Vatican admitted it was wrong.
    (MC, 6/22/02)

1642        Jan 8, Astronomer Galileo Galilei (77) died in Arcetri, Italy. Galileo had 2 daughters consigned to a nunnery and one son, whom he got married into a rich Florentine family. In 1614, Father Tommaso Caccini denounced the opinions of Galileo on the motion of the Earth from the pulpit of Santa Maria Novella, judging them to be erroneous. Galileo went to Rome and defended himself against charges that had been made against him. In 1616, he was admonished by Cardinal Bellarmino and told that he could not defend Copernican astronomy because it went against the doctrine of the Church. Later, in 1632 he was summoned by the Holy Office to Rome. The tribunal passed a sentence condemning him and compelled Galileo to solemnly abjure his theory. He was sent to exile in Siena.  Galileo spent his last years almost totally blind and poor. In 1999 Dava Sobel published "Galileo's Daughter."
    (BHT, Hawking, p.180)(AP, 1/8/98)(WSJ, 10/19/99, p.A24)(MC, 1/8/02)

1645-1715    The Maunder Minimum. A 70-year period, named after astronomer E.W. Maunder, who documented a lack of solar activity during this time. It also marked the coldest period of the "Little Ice Age" that gripped Europe from c1450-c1890.
    (SFC, 11/29/02, p.J6)(SFC, 12/8/03, p.A2)

1673        Jul 24, Edmund Halley entered Queen's College, Oxford, as an undergraduate.
    (MC, 7/24/02)

1695        Jul 8, Christian Huygens (66), Dutch inventor, astronomer, died. He generally wrote his name as Christiaan Hugens, and it is also sometimes written as Huyghens. In his book “Cosmotheros,” published in 1698, he speculated on life on other planets.

1713        Mar 15, Nicolas Louis de Lacaille, astronomer who mapped the Southern Hemisphere, was born.
    (MC, 3/15/02)

1715        May 3, Edmund Halley observed a total eclipse phenomenon: "Baily's Beads."
    (MC, 5/3/02)

1729        James Bradley discovered the aberration of starlight, an apparent shift in the position of a star caused by the finite speed of light and the motion of the Earth in orbit around the Sun. He uses this to determine the speed of light to be 308,3 00 km/sec, remarkably close to the modern value of 299,792 km/sec.

1749        Mar 23, Pierre-Simon Laplace (d.1827), French mathematician, astronomer, physicist, was born. He wrote the 5-volume work “Celestial Mechanics.” In 1998 Charles Couiston Gillespie published his biography “Pierre-Simon Laplace: A Life in Exact Science.”
    (WSJ, 2/19/98, p.A20)(SS, 3/23/02)

1786        Apr 20, John Goodricke (21), English deaf and dumb astronomer, died.
    (MC, 4/20/02)

1822        Aug 25, F. William Herschel (85), German astronomer (discovered Uranus), died.
    (MC, 8/25/02)

1835        The Vatican removed “On the Revolution of the Heavenly Spheres” (1543) by Nicholas Copernicus from its list of banned books.

1839        Sep 9, John Herschel (1792-1871), English astronomer, took the 1st glass plate photograph.

1851            Nov 11, Alvan Clark of Cambridge, Massachusetts, patented a telescope. Clark, a portrait painter interested in astronomy, had made several small lenses and mirrors as a hobby. The fact that he could detect the small residual errors in one of the best lenses Europe could offer convinced him that he could make them as well. After he gained a reputation in Europe the American orders started to come in. The Alvin Clark Company became one of the foremost producers of some of the largest lenses for telescopes in the 1800's.

1855        Mar 13, Percival Lowell (d.1916), astronomer, was born. He predicted the discovery of the planet Pluto. He also wrote “The Soul of the Far East” and “Occult Japan.” He predicted the existence of a planet behind Neptune before Pluto was discovered by Tombaugh in 1930.
    (NH, 12/96, p.22)(HN, 3/13/99)

1851        Jan 6, Leon Foucault (d.1868), French scientist, watched a pendulum swing and shift its plane of motion. This he realized was due to the rotation of the Earth. In 2003 Amir D. Aczel authored "Pendulum: Leon Foucault and the Triumph of Science."
    (WSJ, 8/28/03, p.D18)

1864        May 29, A.H. Borgesius, Dutch amateur astronomer, was born.
    (SC, 5/29/02)

1867        Jun 11, Charles Fabry, found ozone layer in upper atmosphere, was born.
    (SC, 6/11/02)

1867            Oct 31, William Parson (b.1800), 3rd Earl of Rosse and maker of large telescopes, died. Parsons, an Irish astronomer, built the largest reflecting telescope of the 19th century. He learned to polish metal mirrors (1827) and spent the next few years building a 36-inch telescope. He later completed a giant 72-inch telescope (1845) which he named "Leviathan," It remained the largest ever built until decades after his death. He was the first to resolve the spiral shape of objects, previously seen as only clouds, which were much later identified as galaxies independent of our own Milky Way galaxy and millions of light-years away. His first such sighting was made in 1845, and by 1850 he had discovered 13 more. In 1848, he found and named the Crab Nebula (he thought it resembled a crab), by which name it is still known.

1885        May 29, Erwin F. Finlay-Freundlich, British astronomer, was born.
    (SC, 5/29/02)

1887        Albert Michelson and Edward Morley compared the speed of light in the direction of earth’s orbit with the speed of light at right angles to earth’s motion and found it is the same.
    (BHT, Hawking, p.20)

1894        Jul 17, Georges Lemaitre, Belgian astronomer, was born.
    (HN, 7/17/01)

1906        Apr 28, Bartholomeus J "Bart" Bok, Dutch-US astronomer (Milky Way), was born.
    (MC, 4/28/02)

1922        Sep 13, In El Azizia, Libya, a temperature of 136 degrees Fahrenheit (57.8 Celsius) was the hottest ever measured on Earth.
    (MC, 9/13/01)(AP, 7/23/03)

1926        Feb 19, Dr. Lane of Princeton estimated the earth’s age at one billion years.
    (HN, 2/19/98)

1930        May 10, The 1st US planetarium opened in Chicago.
    (MC, 5/10/02)

1934        Mar 9, Uri Gregarin (Yuri Gagarin), first man to orbit the Earth, was born.
    (HN, 3/9/99)

1934        Dec 2, The 5.08-m (200") Mt. Palomar Observatory mirror was cast.
    (MC, 12/2/01)

1947        Jun 24, Flying saucers were "sighted" over Mount Rainier by pilot Ken Arnold.
    (MC, 6/24/02)

1947        Jul 2, An object crashed near Roswell, N.M. The Army Air Force later insisted it was a weather balloon, but eyewitness accounts gave rise to speculation it might have been an alien spacecraft.
    (AP, 7/2/97)

1947        Nov 19, A 200" mirror arrived at Mt. Palomar observatory.
    (MC, 11/19/01)

1948        Jun 3, The 200-inch reflecting telescope at the Palomar Mountain Observatory in California was dedicated. The nearly 5.1 meter Hale telescope was operated by Caltech.
    (AP, 6/3/97)(SFEC, 4/23/00, p.C14)

1949        Feb 1, The 200" (5.08-m) Hale telescope was 1st used.
    (MC, 2/1/02)

1955        Nov 3, An Alabama woman was bruised by a meteor.
    (MC, 11/3/01)

1967        Oct 10, The Outer Space Treaty, which prohibits the placing of weapons of mass destruction on the moon or elsewhere in space, entered into force.
    (AP, 10/10/07)

1959        Jan 22, USAF concluded that less than 1% of UFO's are unknown objects.
    (MC, 1/22/02)

1959        Feb 17, The U.S. launched its first weather station in space, Vanguard II weighing 9.8 kg.
    (HN, 2/17/98)(MC, 2/17/02)

1959        Aug 7, The United States launched Explorer 6, which sent back a picture of the Earth. The satellite, popularly known as the "paddlewheel satellite," featured a photocell scanner that transmitted a crude picture of the earth's surface and cloud cover from a distance of 17,000 miles
    (HFA, '96, p.36)(AP, 8/7/97)(MC, 8/7/02)

1965        Apr 6,    The United States launched the Intelsat I, also known as the "Early Bird" communications satellite.
    (AP, 4/6/08)

1966        Nov 17, The Leonid meteor shower peaked at 150,000+ per hour.
    (MC, 11/17/01)

1967        Jan 27, The US signed the Outer Space Treaty with Russia. More than 60 nations signed a treaty banning the orbiting of nuclear weapons. All weapons of mass destruction were banned from orbit, as was military activity on the moon and other celestial bodies.
    (SFC, 1/28/67, p.A1)(AP, 1/27/98)(SSFC, 7/15/07, p.D1)

1968        Oct 11, Apollo 7, The first manned Apollo mission, was launched from Cape Kennedy with astronauts Wally Schirra, Donn Fulton Eisele and R. Walter Cunningham aboard. It made 163 orbits in 260 hours.
    (AP, 10/11/97)(www.apollomissionphotos.com/index_AP7.html)

1968        John Dobson (53), inventor of the low cost Dobsonian telescope, founded the Sidewalk Astronomers.
    (WSJ, 9/1/04, p.AD10)

1969        May 10, Apollo 10 transmitted the 1st color pictures of Earth from space.
    (MC, 5/10/02)

1972        Aug 21, The US orbiting astronomy observatory Copernicus was launched.

1974        Feb 8, The three-man crew of "Skylab" space station returned to Earth after spending 84 days in space.
    (AP, 2/8/99)

1979        Jul 11, The abandoned U.S. space station Skylab made a spectacular return to Earth, burning up in the atmosphere and showering debris over the Indian Ocean and Western Australia.
    (AP, 7/11/97)(SFC, 6/3/00, p.A6)

1983        Jul 21, The coldest temperature ever measured on Earth was -129 Fahrenheit (-89 Celsius) at Vostok, Antarctica.
    (AP, 7/23/03)

1990        The Cosmic Background Explorer satellite (COBE) proved that cosmic radiation formed a perfect “blackbody” spectrum, which was expected if the universe was once jammed into a very dense state.
    (WSJ, 6/28/01, p.A1)

1991        Apr 5, NASA launched the $670 million Compton Gamma Ray Observatory. It was directed to a suicide plunge in 2000.
    (SFC, 3/24/00, p.A5)(SFC, 6/3/00, p.A6)

1991        Sep 18, The Upper Atmosphere Research Satellite was deployed from the space shuttle Discovery. It measured the ozone hole for the next decade. Operations of the satellite ceased in 2001 due to NASA economics.
    (SFC, 8/24/01, p.A13)

1992        Oct 9, A great meteorite was seen from Kentucky to NY.
    (MC, 10/9/01)

1996        Jul 17, Scientists discovered that the Earth’s solid-iron core rotates 12 miles a year faster than the liquid-iron outer core. The inner core grows about an inch in radius every 50 years. A report was published in Nature.
    (WSJ, 7/18/96, p.A1)(SFC, 7/18/96, p.A6)

1996        Feb, NASA launched a spacecraft to study the asteroid 433 Eros. Project Near Earth Asteroid Rendezvous (NEAR) was part of the Discovery program.
    (SFC, 1/4/99, p.A2)

1996        Jul 17, Scientists discovered that the earth’s solid-iron core rotates 12 miles a year faster than the liquid-iron outer core. The inner core grows about an inch in radius every 50 years. A report was published in Nature.
    (WSJ, 7/18/96, p.A1)(SFC, 7/18/96, p.A6)

1998        Mar 26, In Nevada a new satellite-based survey of the Yucca Mountain site for storing radioactive wastes indicated that the Earth’s crust at the site was stretching 10 times faster than previous studies have shown.
    (SFC, 3/27/98, p.A3)

1998        Nov 17, The  Leonid meter storm was expected to peak and damage was feared to the nearly 500 satellites in orbit. The storm was the result of the Earth’s intersection with the debris field of the comet Tempel-Tuttle, last seen 33 years ago.
    (SFC, 4/28/98, p.A5)(WSJ, 8/28/98, p.A1)(SFEC, 10/4/98, p.A11)

1999        Feb 4, Russian astronauts on Mir planned to deploy a fan-like mirror made of plastic and coated with aluminum for an 18 hour test.
    (SFEC, 1/31/99, p.A23)

2000        Jan 12, Scientists reported that the temperature of the Earth's surface had risen 0.7-1.4 degrees Fahrenheit over the past century and that the Earth has been warming for the past 300 years.
    (SFC, 1/13/00, p.A7)

2000        Jun 4, NASA directed the $670 million crippled Compton Gamma Ray Observatory into a suicide plunge into the Pacific Ocean in a controlled re-entry to avoid debris over populated areas.
    (SFC, 3/24/00, p.A5)(SFC, 6/3/00, p.A6)

2001        Feb 12, The $224 million NEAR-Shoemaker probe was scheduled to end its mission with a landing on the Eros asteroid. The probe completed a 5 year voyage with a successful landing and continued sending signals.
    (SFC, 1/9/01, p.A4)(SFC, 2/13/01, p.A1)

2002        Jun 21, Scientist reported that an asteroid (2002 MN) the size of a soccer field whizzed by Earth on June 14 at a distance of 75,000 miles, a third of the distance to the Moon, the biggest such space rock in decades to get this close.
    (Reuters, 6/21/02)(SFC, 6/21/02, p.A6)

2002        Jul 2, Steve Fossett became the 1st person to fly a balloon solo around the world. On his 6th attempt he completed the journey in 13 days, 12 hours, 16 minutes and 13 seconds. He departed from Australia Jun 19 and covered an estimated 19,428 miles.
    (SFC, 7/3/02, p.A3)

2002        The EU decided to go ahead and launch a satellite navigation network, Galileo, to rival America's Global Positioning System (GPS). Operations were scheduled to begin in 2008.
    (Econ, 1/31/04, p.78)

2002        The Japanese Institute of space and Astronautical Sciences (ISAS) planned to launch its Muses-C to bring asteroid samples back to Earth.
    (SFC, 7/4/98, p.A10)

2003        Oct 29, A powerful geomagnetic storm walloped the Earth, knocking out some airline communications but apparently causing no large power outages or other major problems.
    (AP, 10/29/04)

2003        Dec 17, UC and Cal Tech received 2 grants totaling $35 million to design the world's most powerful telescope, a 30-meter telescope (TMT) to be built on a yet to be chosen mountaintop.
    (SFC, 12/18/03, p.A23)

2004        Mar 18, A 100-foot diameter asteroid passed within 26,500 miles of Earth, the closest-ever brush on record by a space rock.
    (AP, 3/18/04)

2004        May 13, It was reported that scientists had recorded as much as a 10% drop in the amount of sunshine reaching Earth since the 1950s, likely due to atmospheric pollution.
    (SFC, 5/13/04, p.A1)

2004        Aug, A team of Croatian cavers descended 1,693 feet to Earth’s deepest know hole in the Velebit Mountains of Croatia.
    (SFC, 8/17/04, p.A6)

2007        Nov 1, A project called “The Deep Carbon Observatory,” a multidisciplinary, international initiative dedicated to achieving a transformational understanding of Earth's deep carbon cycle, received funding from the Alfred P. Sloan Foundation.
    (Econ, 2/26/11, p.86)(https://dco.gl.ciw.edu/about/history)

2009        Feb 10, The first-ever collision between two satellites occurred over Siberia when a derelict Russian military communications satellite, Cosmos 2251, crossed paths with a US Iridium satellite.
    (AP, 2/12/09)(Econ, 8/21/10, p.65)

2010        Apr 22, The US National Research Council released a study that found the level of acid in oceans increasing by 30% since the start of the Industrial Revolution, some 200 years ago. This came on the 40th observance of Earth Day.
    (SFC, 4/23/10, p.A16)

2010        Sep 29, A Russian firm announced an ambitious bid to fill the vacuum in the space tourism market by stationing an orbiting hotel in the cosmos. Orbital Technologies wants to launch a seven-room station by 2016 but may increase or decrease that capacity based on customer demand.
    (AP, 9/29/10)

2011        Tim Flannery authored “Her on Earth: A natural History of the Planet.”
    (Econ, 3/5/11, p.90)

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