Astronomy Picture of the Day ·
The Millennium that Defined Earth
The Astronomy Picture of the Day for December 31, 1999 is “The Millennium that Defined Earth,” an image. It is credited to Credit: Apollo 8 Crew, NASA. The original explanation runs about 131 words.
From the explanation
“When the second millennium began , people generally knew that the Earth was round , but few saw much of it beyond their local village. As the millennium progressed, humans mapped the continents , circumnavigated the globe , and determined the composition of the Earth .”
— APOD editors, December 31, 1999
Read the full explanation on science.nasa.gov
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At a glance
- Date
- December 31, 1999
- Type
- Image
- Credit
- Credit: Apollo 8 Crew, NASA
- Copyright
- No copyright notice on the entry. Check the credited institution’s own usage rules before reusing it.
- Explanation length
- About 131 words