Astronomy For Dummies Cheat Sheet - dummies
Cheat Sheet

Astronomy For Dummies Cheat Sheet

From Astronomy For Dummies, 4th Edition

By Stephen P. Maran

Astronomy is fascinating, and people have been looking at the stars since the dawn of humanity. Start your study of astronomy by reviewing the accomplishments of the very first astronomers, and then continue looking at important historical markers of the Space Age. Women have played important roles in astronomy, so be sure to check out how their discoveries have shaped what we know about space.

An Astronomical Timeline

The study of astronomy is vast and encompasses a huge amount of information. This chart represents important events in astronomy, like discoveries and inventions that have impacted astronomy through the ages:

2000 B.C. According to legend, two Chinese astronomers are executed for not predicting an eclipse and for being drunk as it happened.

129 B.C. Hipparchos completes the first catalog of the stars.

A.D. 150 Ptolemy publishes his theory of the Earth-centered universe.

970 al-Sufi prepares catalog of over 1,000 stars.

1420 Ulugh-Beg, prince of Turkestan, builds a great observatory and prepares tables of planet and star data.

1543 While on his deathbed, Copernicus publishes his theory that planets orbit around the Sun.

1609 Galileo discovers the moons of Jupiter, craters on Earth’s Moon, the turning of the Sun, and the presence of innumerable stars in the Milky Way with a telescope that he built.

1666 Isaac Newton begins his work on the theory of universal gravitation.

1705 Edmond Halley predicts that a great comet will return in 1758.

1758 On Christmas, farmer/and amateur astronomer Johann Palitzch discovers the return of Halley’s Comet.

1781 William Herschel discovers Uranus.

1791 Benjamin Banneker, the first African-American scientist, begins star observations needed for the geographical survey to establish the future capital city of the United States, Washington, D.C.

1833 Abraham Lincoln and thousands of others see an enormous meteor shower over North America on November 12th and 13th.

1842 Christian Doppler discovers the principle by which sound or light shifts in frequency and wavelength due to the motion of its source with respect to the observer.

1846 Johann Galle is the first person to spot Neptune.

1910 Earth passes through the tail of Halley’s Comet.

1916 Albert Einstein proposes the General Theory of Relativity, which explains the nature of gravity and predicts how the path taken by light is bent when it passes near a massive object such as the Sun.

1923 Edwin Hubble proves that other galaxies lie beyond the Milky Way.

1930 Clyde Tombaugh discovers Pluto.

1931 Karl Jansky discovers radio waves from space.

1939 Hans Bethe explains the energy source of the Sun and other stars.

1940 Grote Reber reports the first radio telescope survey of the sky.

1957 Geoffrey Burbidge, E. Margaret Burbidge, William Fowler, and Fred Hoyle explain how elements form in stars.

1963 Maarten Schmidt discovers that quasars are located at immense distances from the Milky Way and are thus brighter than most other objects in the universe.

1996–1998 Reinhard Genzel (Germany) and Andrea Ghez (United States) and their coworkers find conclusive evidence for a supermassive black hole at the center of the Milky Way.

2003–2004 The Hubble Space Telescope makes repeated images of a region of the sky that, combined together, make up the Hubble Ultra-Deep Field, the deepest picture of the universe ever made.

2015 The Laser Interferometer Gravitational-Wave Observatory reports the detection of gravitational waves from the merger of two black holes about 1.3 billion light-years from Earth.

The Space Age

The Space Age, generally considered started by the launch of the Russian satellite Sputnik, is defined by the events surrounding space exploration and development of space technology. This list maps out major events of the Space Age:

1957 The Soviet Union launches Sputnik 1, the first artificial satellite to orbit Earth.

1958 Using the satellite Explorer 1, James Van Allen discovers Earth’s radiation belts (magnetosphere).

1960 Frank Drake begins the Search for Extraterrestrial Intelligence (SETI) at the National Radio Astronomy Observatory in Green Bank, West Virginia.

1961 Yuri Gagarin makes the first manned space flight.

1963 Valentina Tereshkova is the first woman in space.

1967 Jocelyn Bell Burnell and Anthony Hewish discover pulsars.

1969 Neil Armstrong and Buzz Aldrin walk on the moon.

1979 Using pictures from Voyager 1, Linda Morabito discovers erupting volcanoes on Jupiter’s moon, Io.

1987 Ian Shelton discovers the first supernova since 1604 plainly visible to the naked eye.

1990 The Hubble Space Telescope launches.

1991 Alexander Wolszczan discovers planets orbiting a pulsar — the first known planets outside the solar system.

1995 Michel Mayor and Didier Queloz discover 51 Pegasi B, the first planet of a normal star beyond the Sun.

1998 Two astronomer teams discover that the expansion of the universe is getting faster, perhaps due to a mysterious “dark energy” associated with the vacuum of space.

1999 Mars Global Surveyor finds that Mars may have had an ocean at one time.

2003 The Wilkinson Microwave Anisotropy Probe satellite finds that the universe is 13.7 billion years old.

2012 The Kepler spacecraft finds that there probably are billions of planets in orbit around stars in our galaxy, and the rover Curiosity lands on Mars.

2015 The New Horizons probe explores Pluto and its moons and then heads outward in the Kuiper Belt.

Famous Women in Astronomy

When you’re studying astronomy, don’t forget the women who made an impact in the field. Check out this list of amazing achievements by women astronomers and astrophysicists:


Caroline Herschel (1750–1848) Discovered eight comets.

Annie Jump Cannon (1863–1941) Devised the basic method for classifying the stars.

Henrietta Swan Leavitt (1868–1921) Discovered the first accurate method for measuring great distances in space.

Cecilia Payne-Gaposchkin (1900–1979) Proved that hydrogen is the most abundant chemical element in the stars.

Sally Ride (1951–2012) A trained astrophysicist, she is the first American woman in space.

Vera C. Rubin (1928–2016) Investigated the rotation of galaxies and detected the existence of dark matter.


Jocelyn Bell Burnell Discovered pulsars in her work as a graduate student.

E. Margaret Burbidge Pioneered modern studies of galaxies and quasars.

Wendy Freedman Leader in measuring the expansion rate of the universe.

Gabriela González Leader in detecting gravitational waves from merging black holes.

Carolyn C. Porco Leads the Cassini imaging science team in the study of Saturn and its moons and rings.

Nancy G. Roman As NASA’s first chief astronomer, she led the development of telescopes in space.

Carolyn Shoemaker Discovered many comets, including one that smashed into Jupiter.

Jill Tarter Leader in the search for extraterrestrial intelligence.

Leslie A. Young Leader in the exploration of Pluto.