Launches
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The launch archive is still being mirrored, so this day has no launches listed yet.
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February 29 in spaceflight
Wikipedia records 1 spaceflight and astronomy event on February 29. Below are the pictures NASA published on February 29 in 1 different years — each one taken or released on this exact date.
Recorded events
IN THE RECORD1ENTRY
Spaceflight and astronomy entries from Wikipedia's record of this date, oldest first — from 1504 onward.
Pictures from this date
PUBLISHED1IMAGE
NASA's Astronomy Picture of the Day for February 29, one per year. Some are public domain and some belong to the photographer — each says which.
Published on February 29
NASA’s Astronomy Picture of the Day, for this calendar date in each of the last several years.
2024
Julius Caesar and Leap Days
In 46 BC Julius Caesar reformed the calendar system. Based on advice by astronomer Sosigenes of Alexandria, the Julian calendar included one leap day every four years to account for the fact that an Earth year is slightly more than 365 days long. In modern terms, the time it takes for the planet to orbit the Sun once is 365.24219 mean solar days. So if calendar years contained exactly 365 days they would drift from the Earth's year by about 1 day every 4 years and eventually July (named for Julius Caesar himself) would occur during the northern hemisphere winter. By adopting a leap year with an extra day every four years, the Julian calendar year would drift much less. In 1582 Pope Gregory XIII provided the further fine-tuning that leap days should not occur in years ending in 00, unless divisible by 400. This Gregorian Calendar system is the one in wide use today. Of course, tidal friction in the Earth-Moon system slows Earth's rotation and gradually lengthens the day by about 1.4 milliseconds per century. That means that leap days like today will not be necessary, about 4 million years from now. This Roman silver coin, a denarius, depicts Julius Caesar (left) and Venus, Roman goddess of love.
NASA · public domain
What happened on February 29
1504
Christopher Columbus uses his knowledge of a lunar eclipse that night to convince Jamaican natives to provide him with supplies.
Christopher Columbus ↗
Sources and licences
Event text and thumbnails come from Wikipedia and are used under CC BY-SA 4.0. Images are drawn only from Wikimedia Commons, which does not accept non-free content — each thumbnail links to its file page, where its licence and author are recorded.
Launch records are from The Space Devs’ Launch Library 2. This archive is still being mirrored, so some days are incomplete. Pictures are NASA’s Astronomy Picture of the Day; NASA imagery is generally not subject to copyright, but individual APOD entries are frequently the property of the photographer, and each caption says which applies.
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General-audience astronomy and spaceflight — none of it a textbook.
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Cosmos — Carl Sagan
Still the best single argument for why any of this matters, and it leaves the arithmetic in. For a reader who wants the science, not just the awe.
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Pale Blue Dot — Carl Sagan
The case for leaving Earth, written by someone unsentimental about how hard that is. Suits readers who want the argument rather than the poster.
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Project Hail Mary — Andy Weir
Hard-SF problem solving in The Martian's key — for anyone who liked the engineering more than the peril. The only novel on this list.
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