1577day.year

The first recorded observation from Earth of the Great Comet of 1577 takes place by Aztec astronomers in Mexico, followed by reports from Italy on November 7 and Japan on November 8. Astronomer Tycho Brahe will track the comet from November 13 until January 26 before it departs the Solar System.

Aztec astronomers in Mexico made the first recorded observation of the Great Comet of 1577, predating European sightings. This celestial visitor would soon reshape contemporary understandings of the heavens.
On November 6, 1577, indigenous astronomers in the Aztec capital recorded the appearance of a brilliant comet. Their keen observations predated European reports from Italy on November 7 and Japan on November 8. The Great Comet of 1577 captured the attention of scholars across cultures and continents. Notably, Danish astronomer Tycho Brahe tracked its path from mid-November to late January. Brahe's meticulous measurements challenged the Aristotelian view of an immutable heavens. His work laid groundwork for Kepler’s laws of planetary motion and modern astronomy. This celestial event bridged diverse astronomical traditions and advanced scientific understanding.
1577 Great Comet of 1577 Tycho Brahe
1971day.year

The United States Atomic Energy Commission tests the largest U.S. underground hydrogen bomb, code-named Cannikin, on Amchitka Island in the Aleutians.

The United States conducted its largest underground hydrogen bomb test, Cannikin, on Amchitka Island in 1971, pushing the limits of nuclear experimentation.
In 1971, the United States Atomic Energy Commission conducted Cannikin, the largest underground hydrogen bomb test in U.S. history. Detonated on Amchitka Island in the Aleutian chain, the test was part of Cold War arms development. Engineers drilled deep into the volcanic rock to contain the 5-megaton explosion beneath the surface. Despite safety measures, the blast raised concerns about seismic impacts and ecological risks in the remote environment. Cannikin remains a powerful symbol of nuclear deterrence and the environmental debates surrounding weapons testing. Its legacy continues to influence nuclear policy and the conversation on underground testing safety.
1971 United States Atomic Energy Commission hydrogen bomb Cannikin Amchitka Island Aleutians