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NASA Goddard | Leap Day: It's Not Just Earth @NASAGoddard | Uploaded 6 months ago | Updated 2 days ago
We get a whole extra day today!

But why?

We usually say that there are 365 days in a year, or how long it takes for Earth to orbit the Sun, but it’s really more like 365.25. (Where one day is one rotation of Earth on its axis.) To make up for the missing partial day, we add one day to our calendar about every 4 years. It turns out a few extra hours can really add up!

Leap years allow our calendar year to match the solar year. That accuracy is important for laser communications with spacecraft, long-term climate models of our planet, and more. If we subtracted 5 hours, 46 minutes and 48 seconds every year for many years, it would add up!

Learn more about leap years: https://spaceplace.nasa.gov/leap-year/

Music: "The Most Beautiful Cupcake" by Damien Deshayes [SACEM] from Universal Production Music

Credit: NASA's Goddard Space Flight Center/Scientific Visualization Studio
Katy Mersmann (NASA/GSFC): Producer
Sofie Bates (eMITS): Social Media Support
Molly Wasser (AdNet Systems): Social Media Support

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Video description:
0:00 A woman with brown hair wearing a NASA shirt and holding a calendar open to February. She is pointing to the 29.
0:05 She tosses the calendar aside. Behind her, a greenscreen shows orbit paths of Mercury, Venus, and Earth.
0:10 Dark blue animation of Earth rotating once, labeled 1 day.
0:14 The animation switches to Earth orbiting the Sun, once labeled 1 year.
0:23 Back to the woman talking.
0:27 Animation of Earth, tilted as it would be at the summer solstice. The Northern Hemisphere is tilted toward light coming from offscreen.
0:33 Back to the woman talking.
0:34 Hubble image of Mars, which is a reddish orange globe with white poles.
0:38 Animation of Earth and Mars orbiting the Sun, which pushes into the two labeled dots.
0:44 Back to the woman talking.
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Leap Day: It's Not Just Earth @NASAGoddard