Planets and Moons  ID: 4158

Lunar Eclipses and the Moon's Orbit

The animations on this page illustrate the Moon’s orbit and its role in lunar and solar eclipses. A solar eclipse happens when the Moon’s shadow falls on the Earth, while a lunar eclipse happens when the Earth’s shadow falls on the Moon.

Eclipses can only happen at New and Full Moon, when the Earth, Moon, and Sun are all in a straight line. But they don’t happen every New and Full Moon, because the Moon’s orbit is tilted by about 5 degrees. As the Earth and Moon travel around the Sun, the tilt of the Moon’s orbit changes direction relative to the Sun.

This is analogous to the way the tilt of the Earth causes seasons. Just like winter and summer happen every six months, eclipses tend to occur on a roughly six-month cycle.

Unlike most eclipse shadow diagrams, the first three animations here don’t greatly exaggerate the scale of the Earth and Moon. They are only 2x their true scale. The view is exactly perpendicular to the Earth-Sun line. The angle of the Moon’s orbital tilt and the “tapering” of the shadows are both accurate. The orbit happens to be calculated for the months preceding the April 15, 2014 total lunar eclipse.


For More Information

Visualization Credits

Ernie Wright (USRA): Lead Animator
Dan Gallagher (USRA): Producer
David Ladd (USRA): Producer
Michelle Handleman (USRA): Producer
John Keller (NASA/GSFC): Scientist
Noah Petro (NASA/GSFC): Scientist
Michelle Thaller (NASA/GSFC): Scientist
Laurence Schuler (ADNET Systems, Inc.): Project Support
Ian Jones (ADNET Systems, Inc.): Project Support
Please give credit for this item to:
NASA's Scientific Visualization Studio

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LRO (Lunar Reconnaissance Orbiter)

Data Used:
JPL DE421 also referred to as: DE421
Ephemeris - NASA/JPL
LRO/LOLA/Digital Elevation Map also referred to as: DEM
LRO/LROC/WAC 643nm High Sun Global Mosaic
Note: While we identify the data sets used in these visualizations, we do not store any further details nor the data sets themselves on our site.

This item is part of these series:
The Moon
LRO - Animations

SVS >> Lunar
SVS >> Moon
SVS >> Lunar Reconnaissance Orbiter
SVS >> Eclipse
SVS >> Lunar Eclipse
NASA Science >> Planets and Moons