Science History: What Happened On This Day
Find your date below: 29 days of the year, each with a science event from history between 1758 and 2020, its year and a link to the full story in our history calendar.
Discoveries in astronomy, physics, biology and medicine: new planets, moons and comets, X-rays and gravitational waves, and firsts in treating disease. Every day is also a round of Years Ago, our daily history game, so days playing today or in the next 30 days are left out until they have played.
March
March 7, 2009
NASA launches the Kepler space telescope to search for Earth-sized planets orbiting other stars.
March 13, 1781
William Herschel spots Uranus from his garden in Bath, the first planet discovered with a telescope.
March 23, 1950
The World Meteorological Organization is established as its founding convention comes into force.
March 27, 2020
NASA's NEOWISE space telescope discovers a comet that later becomes a spectacular naked-eye sight.
April
April 5, 1991
Space Shuttle Atlantis launches the Compton Gamma Ray Observatory, the second of NASA's Great Observatories.
April 6, 1869
The American Museum of Natural History is founded in New York City.
April 18, 2018
NASA launches TESS, a space telescope that searches for planets around nearby bright stars.
April 25, 1953
Watson and Crick publish their double-helix model of DNA in the journal Nature.
May
June
June 5, 1764
Charles Messier records the Trifid Nebula, a glowing cloud of gas split by dark lanes, in his catalogue.
July
July 23, 1999
Space Shuttle Columbia launches the Chandra X-ray Observatory, commanded by Eileen Collins.
August
August 13, 1898
Gustav Witt in Berlin discovers 433 Eros, the first asteroid found to come close to Earth.
August 14, 1991
Physicist Paul Ginsparg starts the arXiv preprint server for sharing research papers.
August 15, 1977
The Big Ear radio telescope in Ohio detects the "Wow! signal," a strong radio burst never detected again.
August 18, 1868
During a total solar eclipse over India, Pierre Janssen observes a mysterious yellow line that reveals helium.
August 24, 2006
The International Astronomical Union votes on a definition of 'planet' that reclassifies Pluto as a dwarf planet.
August 25, 2003
NASA launches the Spitzer Space Telescope to observe the universe in infrared light.
September
September 1, 1804
German astronomer Karl Harding discovers Juno, the third asteroid ever found.
September 14, 2015
LIGO detects gravitational waves for the first time, from two black holes merging over a billion light-years away.
September 23, 1846
Astronomers in Berlin find Neptune, guided by a position predicted by mathematics alone.
September 28, 1928
Alexander Fleming spots a mold wiping out bacteria in a forgotten culture dish, the first step toward penicillin.
September 29, 1954
CERN, the European laboratory for particle physics near Geneva, officially comes into being.
October
October 8, 1958
Swedish engineer Arne Larsson becomes the first person to receive a fully implanted heart pacemaker.
October 10, 1846
English astronomer William Lassell discovers Triton, the largest moon of Neptune.
October 16, 1846
Surgeons in Boston give the first successful public demonstration of ether anesthesia during an operation.
December
December 3, 1904
Charles Dillon Perrine discovers Himalia, a small outer moon of Jupiter.
December 19, 2013
The European Space Agency launches Gaia, a spacecraft built to map more than a billion stars.
December 25, 1758
Amateur astronomer Johann Georg Palitzsch spots the return of Halley's Comet, confirming Edmond Halley's prediction.
Frequently asked questions
- What counts as a science event?
- Discoveries in astronomy, physics, biology and medicine: new planets, moons and comets, X-rays and gravitational waves, and firsts in treating disease.
- Why are some days of the year missing?
- Our history calendar has one event for each day, and this page lists the days whose event is about science. Every day is also a round of Years Ago, our daily history game, so a day playing today or in the next 30 days is left out until it has played, and then comes back.
- How are the dates checked?
- Each event was checked against at least 2 independent sources, linked on its day in the history calendar, and the summary is written in our own words.
More history
Play today’s puzzleHistory calendar
Other topics: