Shop Windows to the Universe

Our Glaciers: Then and Now activity kit helps you see the changes taking place in glaciers around the world. See all our activity kits and classroom activities.
This image explains how the Earth's shadow causes a lunar eclipse. Notice the difference between the umbra and the penumbra.
Click on image for full size
Windows to the Universe original image

Lunar Eclipses

A lunar eclipse is when the Earth's shadow blocks sunlight from reaching the Moon. It can only happen when there is a full moon. The Sun, Earth and Moon all need to be in a straight line too.

The Earth's shadow has two parts called the penumbra and the umbra. The umbra is much darker than the penumbra. When the Moon passes through the umbra, it is called a total eclipse.

When only part of the Moon passes through the umbra, it's called a partial eclipse. And when the Moon goes through the penumbra, it's called a penumbral eclipse. Have you seen an eclipse?

Last modified June 20, 2001 by Jennifer Bergman.

Shop Windows to the Universe Science Store!

Learn about Earth and space science, and have fun while doing it! The games section of our online store includes a climate change card game and the Traveling Nitrogen game!

Windows to the Universe Community

News

Opportunities

You might also be interested in:

Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Lunar Eclipse January 20, 2000

There's a lunar eclipse this week! Thursday night, all of North America will see the eclipse. It starts at 10:00 pm Eastern Time. A lunar eclipse is different than a solar eclipse. During a lunar eclipse,...more

Total Lunar Eclipse

There will be an eclipse of the Moon on Thursday night, May 15, 2003. The shadow of the Earth will fall on the Moon, and the Moon will get dark! The Moon will not be so dark that you can't see it. The...more

Eclipse of the Moon

There will be an eclipse of the Moon on Saturday night, November 8, 2003. The shadow of the Earth will fall on the Moon, and the Moon will get dark! The Moon will not be so dark that you can't see it....more

Lunar Eclipse in October 2004

There will be an eclipse of the Moon on Wednesday night, October 27, 2004 (or the morning of the 28th if you are in Europe or Africa). The shadow of the Earth will fall on the Moon, and the Moon will get...more

Universal Time

When it is noon where you live, it is midnight on the opposite side of the world. Usually when we think of time, we mean "the time of day where I live". If we say something happened at 9 AM, we mean it...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA