On April 11, 1986, with about 63 million kilometers (39 million miles), Halley’s Comet made its closest approach to Earth on its outbound journey (while moving away from the Sun).
Today’s (April 11) story of what happened this day in Science, Technology, Astronomy, and Space Exploration history.
Halley’s 1986 Approach
The 1986 approach of Halley’s Comet was the least favorable on record. Many observers around the world were disappointed because the famous comet was barely visible to the naked eye.
In February 1986, the comet and the Earth were on opposite sides of the Sun, creating the worst possible viewing circumstances for Earth observers during the previous 2,000 years. Additionally, increased light pollution from urbanization in the 20th century caused many people to fail in attempts to see the comet.
Halley’s comet displayed much better shows during some of its previous visits:
- In 12 BC, it was watched by the Chinese people for two months.
- In 374 AD and 607, the comet passed only 13.5 million kilometers (8.4 million miles) from Earth.
- In 837 Ad, it made the closest-ever approach to Earth: only 5 million kilometers! (3.1 million miles)
- In 1066, the comet was so bright that it terrified millions of Europeans. It was also seen for over two months in China.
- In 1222, it was described by Japanese astronomers as being “as large as the half-moon”.
- In 1456, it was observed in Italy by the Italian mathematician, astronomer, and cosmographer Paolo Toscanelli (1397 – 10 May 1482). Toscanelli said the comet’s head was “as large as the eye of an ox”, with a tail “fan-shaped like that of a peacock”.
Astronomers are now able to observe the comet at any point in its orbit. In December 2023, it is calculated to reach the farthest point in its orbit from the Sun.
April 11 in Science, Technology, Astronomy, and Space Exploration history
- 1986: Halley’s Comet made the closest approach to Earth.
- 1970: Apollo 13, the seventh crewed mission in the United States’ Apollo space program and the third meant to land on the Moon was launched.
- 1P/Halley on the NASA Solar System Exploration website
- Halley’s Comet on Wikipedia
- April 11 on the Today in Science History website
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