1770day.year
Lexell's Comet is seen closer to the Earth than any other comet in recorded history, approaching to a distance of 0.0146 astronomical units (2,180,000 km; 1,360,000 mi).
Lexell’s Comet passed closer to Earth in 1770 than any other recorded comet, approaching within 0.0146 AU.
On July 1, 1770, astronomers observed Lexell’s Comet making its closest recorded approach to Earth, coming within approximately 2.18 million kilometers. Discovered by Anders Johan Lexell the previous year, the comet’s trajectory was calculated by Joseph-Louis Lagrange. Its passage offered an unprecedented opportunity to study orbital dynamics and comet behavior. Despite its brightness, Lexell’s Comet was never observed again after its encounter, as a close pass by Jupiter altered its orbit. The event spurred advances in celestial mechanics and the understanding of how planetary interactions shape comet paths. Today, this remarkable close approach remains a benchmark in the history of cometary science.
1770
Lexell's Comet
astronomical units
1819day.year
Johann Georg Tralles discovers the Great Comet of 1819, (C/1819 N1). It is the first comet analyzed using polarimetry, by François Arago.
German physicist Johann Georg Tralles discovered the Great Comet of 1819, the first comet studied by polarimetry.
On July 1, 1819, astronomer Johann Georg Tralles first spotted the Great Comet C/1819 N1, which quickly brightened and became visible to the naked eye across Europe. French scientist François Arago applied pioneering polarimetric techniques to analyze the comet’s coma, marking the first use of polarization in cometary study. Their observations provided fresh insights into the composition and light-scattering properties of comets. The international collaboration among observatories during its appearance spurred advancements in astrophysical instrumentation. Today, the Great Comet of 1819 is celebrated as a milestone in 19th-century astronomy and the development of scientific methods.
1819
Johann Georg Tralles
Great Comet of 1819
polarimetry
François Arago
1841day.year
Thomas Lempriere and James Clark Ross carve a marker on the Isle of the Dead in Van Diemen's Land to measure tidal variations, one of the earliest surviving benchmarks for sea level rise.
In 1841, Thomas Lempriere and James Clark Ross carved a tidal benchmark on the Isle of the Dead in Van Diemen’s Land to measure sea level changes.
On July 1, 1841, surveyor Thomas Lempriere and explorer James Clark Ross inscribed a marker on a cliff at the Isle of the Dead near Hobart, then called Van Diemen’s Land. The benchmark served to record high-water marks and tidal variations, creating one of the earliest surviving sea level measurements. Over subsequent decades, scientists revisited the site to track coastal change, offering valuable data for understanding long-term sea-level trends. The Isle of the Dead marker now stands as a testament to early environmental monitoring and colonial surveying practices. It is recognized for its contribution to climate science and maritime safety. Visitors can view the preserved benchmark as part of Tasmania’s cultural heritage.
1841
Thomas Lempriere
James Clark Ross
Isle of the Dead
Van Diemen's Land
sea level rise
1858day.year
Joint reading of Charles Darwin and Alfred Russel Wallace's papers on evolution to the Linnean Society of London.
Charles Darwin and Alfred Russel Wallace’s papers on evolution were jointly read to the Linnean Society of London in 1858.
On July 1, 1858, the Linnean Society of London hosted a landmark presentation featuring papers by Charles Darwin and Alfred Russel Wallace, both outlining the theory of natural selection. The joint reading ensured that credit for the discovery was shared, preventing priority disputes. Although the meeting drew little public attention at the time, it laid the groundwork for Darwin’s publication of On the Origin of Species in 1859. The event marked a pivotal moment in biological science, uniting two independent lines of thought into a cohesive theory. Today, the 1858 reading is celebrated as the formal birth of evolutionary biology and a testament to collaborative scientific inquiry.
1858
Charles Darwin
Alfred Russel Wallace
evolution
Linnean Society of London
1874day.year
The Sholes and Glidden typewriter, the first commercially successful typewriter, goes on sale.
The Sholes and Glidden typewriter, the first commercially successful model, went on sale on July 1, 1874.
On July 1, 1874, E. Remington and Sons introduced the Sholes and Glidden typewriter, the first commercially viable typing machine. Invented by Christopher Latham Sholes, Carlos Glidden, and Samuel W. Soule, it featured the QWERTY keyboard layout that persists today. The typewriter revolutionized written communication by increasing speed, consistency, and legibility. Early users included businesses, journalists, and government offices seeking efficient documentation. Its success spurred rapid advancements in office technology and gave rise to the modern secretarial profession. The Sholes and Glidden model marked a pivotal moment in industrial design and mass communication.
1874
Sholes and Glidden typewriter
typewriter
1881day.year
The world's first international telephone call is made between St. Stephen, New Brunswick, Canada, and Calais, Maine, United States.
The first international telephone call is placed between St. Stephen, New Brunswick, and Calais, Maine, marking a milestone in global communication.
On this day in 1881, the world’s first international telephone call connected the towns of St. Stephen, New Brunswick, and Calais, Maine. Inventor Alexander Graham Bell’s technology crossed national borders, proving the potential of voice communication over long distances. The successful call demonstrated that telephony could unite distant communities and laid the groundwork for modern global telecommunications. It spurred further innovations in infrastructure and set the stage for today’s interconnected world. This achievement marked a turning point in how people exchanged information across nations.
1881
telephone call
St. Stephen, New Brunswick
Calais, Maine
1908day.year
SOS is adopted as the international distress signal.
SOS is adopted as the international maritime distress signal, standardizing emergency communication at sea.
In 1908, the International Radiotelegraphic Convention in Berlin officially designated 'SOS' as the standard Morse code distress signal. Chosen for its simple and unmistakable pattern (... --- ...), SOS replaced a variety of local signals, ensuring clarity during emergencies. The new standard was rapidly adopted by ships and coastal radio stations worldwide. It revolutionized maritime safety by enabling faster and more reliable distress alerts. The adoption of SOS is considered a landmark in communication history, credited with saving countless lives at sea.
1908
SOS
distress signal
1915day.year
Leutnant Kurt Wintgens of the then-named German Deutsches Heer's Fliegertruppe army air service achieves the first known aerial victory with a synchronized machine-gun armed fighter plane, the Fokker M.5K/MG Eindecker.
On July 1, 1915, German Leutnant Kurt Wintgens achieved the first recorded fighter plane kill using a synchronized machine gun.
On July 1, 1915, Leutnant Kurt Wintgens of the German Fliegertruppe achieved history's first known aerial victory by employing a Fokker Eindecker with synchronized machine guns. Until then, pilots had to avoid firing through a spinning propeller by mounting guns at awkward angles. The synchronization gear allowed bullets to pass safely between the blades, giving Wintgens a crucial tactical advantage. This breakthrough ushered in a new era of fighter aircraft dominance in World War I. The success of the Eindecker design spurred both sides to develop more advanced synchronization mechanisms and dedicated fighters. Wintgens’s victory demonstrated the deadly potential of armed aircraft and fundamentally changed air combat doctrine. Aviation historians often cite this moment as the birth of the modern fighter plane.
1915
Leutnant
Kurt Wintgens
Deutsches Heer's
Fliegertruppe
the first known aerial victory
synchronized machine-gun
Fokker M.5K/MG
1931day.year
Wiley Post and Harold Gatty become the first people to circumnavigate the globe in a single-engined monoplane aircraft.
On July 1, 1931, Wiley Post and Harold Gatty became the first to circumnavigate the globe in a single-engined monoplane, flying the Winnie Mae.
On July 1, 1931, pilots Wiley Post and Harold Gatty completed the first round-the-world flight in a single-engined monoplane. Departing from Roosevelt Field in Long Island, they navigated over 15,000 kilometers in their Lockheed Vega named Winnie Mae. The 8-day journey included stops in Greenland, Europe, and Asia, showcasing advanced flight planning and endurance. Their achievement demonstrated the reliability of modern aircraft and the potential for global air travel. The flight set a new speed record for the circumnavigation and captured international headlines. Post and Gatty’s success inspired further long-distance aviation feats and contributed to public enthusiasm for flight.
Wiley Post
Harold Gatty
single-engined monoplane
1946day.year
Crossroads Able is the first postwar nuclear weapon test.
On July 1, 1946, Crossroads Able, the first nuclear test since World War II, was detonated at Bikini Atoll.
On July 1, 1946, Crossroads Able, the first nuclear test since World War II, was detonated at Bikini Atoll in the Pacific. It was part of Operation Crossroads, designed to study the effects of nuclear weapons on naval vessels. A bomb was suspended 90 feet above a target fleet of surplus warships. The blast destroyed and heavily damaged several ships, providing critical data on blast and radiation damage. Fallout from the test sparked concerns about environmental contamination and public safety. Crossroads Able influenced future nuclear testing protocols and raised global awareness of atomic power.
1946
Crossroads Able
1957day.year
The International Geophysical Year begins.
On July 1, 1957, the International Geophysical Year (IGY) commenced, launching a global scientific collaboration.
On July 1, 1957, the International Geophysical Year (IGY) commenced, marking an unprecedented global scientific collaboration. Lasting until the end of 1958, the program involved researchers from over 60 countries studying Earth's physical properties. Major achievements included the deployment of Antarctic research stations and pioneering data on polar ice, magnetism, and seismology. The IGY also witnessed the launch of Sputnik 1, ushering in the space age and satellite geophysics. Scientists discovered the Van Allen radiation belts around Earth through coordinated satellite observations. This initiative fostered unprecedented data sharing and set the stage for future international research efforts.
1957
International Geophysical Year
1959day.year
Specific values for the international yard, avoirdupois pound and derived units (e.g. inch, mile and ounce) are adopted after agreement between the US, the United Kingdom and other Commonwealth countries.
The US, UK, and Commonwealth nations standardize the international yard, pound, and their derived units by precise metric definitions.
On July 1, 1959, an international agreement took effect to define the yard and the avoirdupois pound by precise metric values.
Member countries including the United States, the United Kingdom, and other Commonwealth states ratified identical standards for length and weight.
The inch was set to 25.4 millimeters exactly, and the pound to 0.45359237 kilograms, eliminating previous small discrepancies.
This harmonization facilitated global trade, scientific research, and engineering by ensuring consistency in measurements.
Derived units such as the mile, foot, and ounce also gained defined metric equivalents under the new system.
The move eased technical communication and reduced conversion errors in industries ranging from manufacturing to aviation.
It remains the basis for imperial and US customary units used today.
1959
yard
avoirdupois pound
ounce
agreement
Commonwealth