1914day.year
The Franck–Hertz experiment, a pillar of quantum mechanics, is presented to the German Physical Society.
Franck and Hertz present their experiment to the German Physical Society, providing key evidence of quantized atomic energy levels.
On April 24, 1914, physicists James Franck and Gustav Hertz presented their groundbreaking experiment to the German Physical Society.
The Franck–Hertz experiment demonstrated discrete energy absorption by mercury atoms when bombarded with electrons.
Observing current drops at specific energy intervals, they provided direct evidence for quantized atomic energy levels.
Their work validated Niels Bohr’s early atomic model and advanced quantum theory foundations.
The experiment became a pillar of modern physics, illustrating energy quantization in a laboratory setting.
For this achievement, Franck and Hertz would later be awarded the 1925 Nobel Prize in Physics.
1914
Franck–Hertz experiment
quantum mechanics
German Physical Society
1967day.year
Cosmonaut Vladimir Komarov dies in Soyuz 1 when its parachute fails to open. He is the first human to die during a space mission.
In 1967, Soviet cosmonaut Vladimir Komarov became the first human to die during a space mission when Soyuz 1’s parachute failed to open upon re-entry.
On April 24, 1967, Soyuz 1 re-entered Earth’s atmosphere carrying cosmonaut Vladimir Komarov after a mission beset by technical malfunctions. During descent, the spacecraft’s main parachute did not deploy, causing a fatal crash near Orenburg, Russia. Komarov’s death marked the first in-flight fatality in crewed space exploration. The tragedy exposed the dangers of rapid space competition and led Soviet engineers to overhaul Soyuz safety systems and flight protocols. In the aftermath, crewed launches were temporarily suspended to address critical design flaws. Komarov was posthumously celebrated as a brave pioneer, and monuments were erected in his honor. His story remains a sobering reminder of the human cost of exploring beyond our atmosphere.
1967
Cosmonaut
Vladimir Komarov
Soyuz 1
parachute
1970day.year
China launches Dong Fang Hong I, becoming the fifth nation to put an object into orbit using its own booster.
China becomes the fifth nation to place its first satellite, Dong Fang Hong I, into orbit using its own rocket.
On April 24, 1970, China successfully launched Dong Fang Hong I, marking its entry into the spacefaring nations.
The satellite was carried by a Long March 1 rocket from the Jiuquan Satellite Launch Center.
This achievement made China the fifth country to independently deploy a satellite into Earth orbit.
Dong Fang Hong I transmitted a Chinese folk song, showcasing the country's technological capabilities.
The mission represented a significant milestone in China's space program and national pride.
It laid the foundation for the subsequent development of China's space exploration efforts.
1970
Dong Fang Hong I
1990day.year
STS-31: The Hubble Space Telescope is launched from the Space Shuttle Discovery.
The Space Shuttle Discovery launches the Hubble Space Telescope, opening a new era in astronomy.
On April 24, 1990, NASA launched the Hubble Space Telescope aboard Space Shuttle Discovery on mission STS-31.
Hubble was designed to observe the universe without atmospheric distortion, offering unprecedented clarity.
The telescope's deployment represented decades of collaboration among American and international space agencies.
Equipped with state-of-the-art instruments, Hubble provided deep-field images and revolutionary data on cosmic phenomena.
Its observations led to breakthroughs in understanding galaxy formation, dark energy, and exoplanets.
Hubble remains one of the most productive scientific instruments in history, transforming our view of the cosmos.
1990
STS-31
Hubble Space Telescope
Space Shuttle
Discovery