20th century
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The twentieth century of the Common Era began on January 1, 1901 and ended on December 31, 2000, according to the Gregorian calendar.
20th Century Exploration
This section covers the twentieth century and the important astronomical events and people from it. The people section covers the three most-prominent figures: Edwin Hubble, Albert Einstein, and Stephen Hawking.
The 19th century was also a time for mass involvement in astronomy. Expeditions to observe eclipses were popular with both professional and amateur astronomers alike. Astronomy clubs and societies were set up.
These changes were not restricted to the third century, but took place slowly over long periods of time, and were punctuated with many temporary reversals.
Beowulf might have been written down in this century, though it could also have been in the 8th century
Viking attacks on Europe begin
Oseberg ship burial ...
On Saturday September 24, the Observatory celebrated a century of its history by welcoming back a new Oddie refractor, created by artist Tim
Wetherell.
4th century
Greece thus entered the 4th century under a Spartan hegemony, but it was clear from the start that this was weak.
21st Century Explorer Podcast Competition →
Create an audio recording or video short to answer the question: 'What do you think is NASA's greatest exploration achievement in the past 50 years and why?' Submissions are due Jan. 4, 2008.
21st Century. Of course, today, in addition to optical telescopes, astronomers have instruments to receive radio waves and other kinds of energy from objects too far away to be seen.
- Century Plaza Hotel Photos - Absolute Spa at the Century in Vancouver,British Columbia Canada
- Movies Filmed on Location in Vancouver, British Columbia
- English Bay Sunset, Vancouver, British Columbia ...
A century after Martin Luther broke away from the Roman church, religious wars sweep Europe. The 30 years' war (1618-1648) devastates Germany and establishes Sweden as a major military power.
[A "century" is 100 runs at cricket, a British game similar to baseball. A "Test" is a cricket match at the national level, and "Lords" is a famous playing field in Britain where cricket games are held.
Each century, a score of comets brighter than Comet Halley have been discovered. Yet, they appear without warning and will not be seen again.
16th Century Paradigm
Occam's Razor
Copernicus's Heliocentric Universe
Tycho Brahe's excellent observations
Review Questions ...
17th century
This is a collaboratively edited writeup. You are encouraged to assimilate and supersede it.
1609 ...
In the century following the death of Copernicus and the publication of his theory of the solar system, two scientists"Johannes Kepler and Galileo Galilei"made indelible imprints on the study of astronomy.
A 12th century text by Bhaskara II says: "sampan revolves negatively 30000 times in a Kalpa of 4320 million years according to Suryasiddhanta, while Munjala and others say ayana moves forward 199669 in a Kalpa, and one should combine the two, ...
So the century-long search for a second moon of the Earth seems to have succeeded, after all, even though this 'second moon' turned out to be entirely different from anything anybody had ever expected.
* 21st-century paleontology has continued to provide support for evolutionary science. With access to many high-quality fossil beds, hardly a month goes by without a major new fossil discovery.
The 20th Century
So far, in 20th century 40 more major bodies (and thousands of comets and asteroids) have been discovered (27 by the Voyager probes) more than doubling the count again to 71: Himalia 1904 C. Perrine Elara 1905 C.
The 24th Century Technical Manual-Reference books
American Cinematographer-Behind-the-scenes magazine
Bajoran assault vessel-Studio model
Bajoran interceptor-Studio model
Bajoran raider-Studio model
Borg cube-Studio models ...
The 17th century was a time of intense religious feeling, and nowhere was that feeling more intense than in Great Britain.
In the 2d century ad, the Greeks combined celestial theories with carefully planned observations.
In the 5th century B.C. the Athenian astronomer Euctemon, according to Geminus of Rhodes, compiled a weather calendar in which Aquarius, Aquila, Canis major, Corona, Cygnus, Delphinus, Lyra, Orion, Pegasus, ...
In the 4th century BC, Greek philosophers deduced that the stars were fixed on a celestial sphere which rotated about the spherical Earth. The planets, Sun and the Moon moved in a fluid substance called ether between the Earth and the stars.
Nineteenth-century hypothesis that depicted the many changes evinced by the geological record as having resulted from cataclysms occurring during a relatively brief period of history. Compare uniformitarianism.
Cathode-Ray Tube (CRT) ...
More than a century of weather observations and three computer models helped scientists led by the National Center for Atmospheric Research (NCAR) to arrive at an answer to the riddle of how such a small variation in the energy that reaches Earth ...
In the second century BC, the Greek astronomer Hipparchus divided the stars into six brightness groups called magnitudes (now apparent visual magnitudes (m or V), first magnitude the brightest, sixth the faintest.
The twentieth century has seen cosmology transformed from metaphysics into a branch of physics, ...
ShareAlmost a century ago, astronomers Shapley and Melotte began classifying star clusters. This rough, initial go-around took in the apparent number of stars and the compactness of the field - along with color.
A quarter of a century ago, astronomers discovered distant objects rare, ...
From the tenth century onwards, the works of Ptolemy were reintroduced into Europe by Islamic Arab incursions and the Greek books were translated from Arabic into Latin, the scientific language of the day.
During the 19th century, much was learned about meteorites through the use of chemical analyses and the petrographic microscope.
In the mid-20th century, astronomers began to consider the idea that, during the formation of the solar system, Jupiter was responsible for interrupting the accretion of a planet from a swarm of planetesimals located about 2.
In the sixteenth century, Copernicus suggested that Mars' pecularities could be explained by assuming that the planets (including Earth) revolve around the Sun -- instead of the planets and the Sun revolving around the Earth.
In the late 19th century, seeing was communicated almost entirely as a qualitative judgment, expressed in terms that unhappily combine a physical fact with the astronomer's reaction to the fact.
In the last half-century we have come to believe that the Universe contains objects that are truly bizarre as measured in human terms.
Neutron Stars and Pulsars
Black Holes
Quasars
Exploding and Colliding Galaxies ...
cock: a 17th century term for a style or gnomon, particularly on Butterfield dials. Named from the likeness to a bird's tail. The term is also used for a part of a watch or clock, holding the bearing for the pendulum or balance wheel.
By the early 19th century it became evident that the orbit of Uranus did not follow Newton's law of Gravitation. Many astronomers began to question whether Newton's theory of gravitation applied to an object so far from the sun.
And it was in this century that Einstein, the genius with the bad hairday and mismatched socks, stated that the speed of light was the limiting speed. Nothing in the universe can go faster than light.
The ghost of the universe has been caught.
Aristotle - 4th Century BC
Image of Plato and Aristotle (384 - 322 BC) from the Stanza della Segnatura in the Vatican, in the painting "School of Athens" by Raphael.
The branch of 20th century physics that describes atoms and radiation; the theory involves bundles of energy known as quanta.
quark - (n.) ...
The above twentieth century space systems have counterparts in the world of sci-fi technology: PROPULSION: (FTL - faster than light propulsion, Cavorite-antigravity material, warp drive - a means of exceeding the speed of light), ...
secular (NASA SP-7, 1965) Pertaining to long periods of time on the order of a century, as secular perturbations, secular terms.
Week 111 - 21st Century Waves
Week 110 - Kentucky Space
Week 109 - Twisted Physics
Week 108 - Starts With A Bang!
Week 107 - Innumerable Worlds
Week 106 - The Next Big Future
Week 105 - Discovery Channel Space Disco
Week 104 - Mang's Bat Page ...
Galaxies were not recognized as a distinct kind of nebular object until the late 19th century, when visual spectroscopy (Huggins) of the Andromeda spiral (M31) showed a continuous spectrum.
At the beginning of this century the big question was whether or not the nebulae were entities that lived with in our Milky Way, or were instead far away and "Milky Ways" (i.e. galaxies) in their own right.
Thanks to Susan Watanabe and Mary Beth Murrill of Media Relations for their reviews and advice pertaining to the 21st Century Edition.
Subrahmanyan Chandrasekhar was one of the foremost astrophysicists of the twentieth century. He was one of the first scientists to couple the study of physics with the study of astronomy.
Discrete Topographic and Orographic Clouds have been observed on Mars for over a century. In 1907, a remarkable, recurring W-shaped cloud formation was observed each late-spring afternoon in the Tharsis-Amazonis region [Slipher, 1962].
A century ago, Eta Carinae abruptly brightened to an apparent magnitude of -0.8 and was, briefly, the second brightest star in the sky.
Using a well known 19th century chemistry principle, these spacecraft will use material they find on Mars to produce fuel for the trip back home.
It is estimated that about 3 supernovae occur per century per galaxy. In the modern era all the supernovae that have been observed have been in other galaxies. The last observed supernova in our galaxy was one described by Kepler in 1604.
Apus is a constellation in the southern hemisphere, first documented in a 17th century celestial atlas included in Johann Bayer's Uranometria.
A century later Giovanni Borelli concluded that the orbits were parabolic and that comets passed through the solar system but once, never to return.
This technical term is a historic relic of the 17th century, before energy and momentum were understood. In modern terminology, action has the dimensions of energyÃ-time.
During the second century BC, a man by the name of Hipparchus calculated the length of the tropical year within six minutes of the currently known value.
They have useful Power Point introductory talks, free software, a range of educational pages and the largest repository of variable star records in the world dating back a century.
Detail from Book X, Chapter 7, of a 13th century translation of the Almagest made from Arabic to Latin in Spain in 1175 by Gerard of Cremona.
In the middle of the 19th century, the technology to cast large metal coated glass mirrors did not exist and Lord Rosse was forced to use "speculum" metal instead.
 See also: Time, Second, Earth, Period, Light
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