<p><strong>On Saturday the moon (pictured over Lisbon, Portugal's Tagus River) made its closest approach to<a href="http://science.nationalgeographic.com/science/space/solar-system/earth.html"> Earth</a> in 18 years—making the so-called supermoon the biggest full moon in years. (Get the <a href="http://news.nationalgeographic.com/news/2011/03/110318-supermoon-earth-japan-earthquake-tsunami-science-space-biggest-full-moon/">full story of the supermoon</a>.)</strong></p><p>The monthly<a href="http://science.nationalgeographic.com/science/space/solar-system/full-moon-article.html"> full moon</a> always looks like a big disk, but because its orbit is egg-shaped, there are times when the moon is at perigee—its shortest distance from Earth in the roughly monthlong lunar cycle—or at apogee, its farthest distance from Earth.</p><p>Likewise, because the size of the moon's orbit varies slightly, each perigee is not always the same distance away from Earth.</p><p>Saturday's supermoon was just 221,566 miles (356,577 kilometers) away from Earth—making the supermoon about 20 percent brighter and 15 percent bigger than a regular full moon, said Anthony Cook, astronomical observer for the<a href="http://www.griffithobservatory.org/"> Griffith Observatory</a> in Los Angeles.</p><p>Before the supermoon, astronomer <a href="http://www.adlerplanetarium.org/researchcollections/research/researchers">Geza Gyuk</a> said, "Look for the full moon as it rises above the eastern horizon as the sun sets below the western horizon—it will be a beautiful and inspiring sight."</p><p>That's advice a lot of photographers, including National Geographic fans, one of whom contributed this picture, apparently took to heart.</p><p>(See more readers' <a href="http://ngm.nationalgeographic.com/myshot/search?keywords=supermoon">supermoon pictures</a>.)</p><p><strong>More Moon Pictures, Facts, and News</strong></p><ul class="bullets"><li><a href="http://photography.nationalgeographic.com/photography/photos/moons-and-sunsets-photo-gallery/">National Geographic Moon Pictures and Prints</a></li><li><a href="http://blogs.ngm.com/blog_central/2011/03/the-new-moon.html">New Moon Map From National Geographic</a></li><li><a href="http://ngm.nationalgeographic.com/1969/12/moon-landing/astronauts-text">1969 National Geographic Article on First Moon Landing</a></li><li><a href="http://news.nationalgeographic.com/news/2002/12/1218_021218_moon.html">Full Moon Effect on Behavior Minimal, Studies Say</a></li><li><a href="http://news.nationalgeographic.com/news/2010/01/100129-biggest-full-moon-2010-mars/">Year's Biggest Full Moon, Mars Create Sky Show (2010)</a></li><li><a href="http://science.nationalgeographic.com/science/space/space-exploration/moon-myth-quiz/">Moon Quiz</a><a href="http://news.nationalgeographic.com/news/2002/12/1218_021218_moon.html"></a></li><li><a href="http://news.nationalgeographic.com/news/2010/06/100614-moon-water-hundred-lunar-proceedings-science/">Moon Has a Hundred Times More Water Than Thought</a></li><li><a href="http://news.nationalgeographic.com/news/2010/12/photogalleries/101221-lunar-eclipse-2010-pictures-winter-solstice-december-20-nasa-space-science-pictures/">Moon Eclipse Pictures</a></li><li><a href="http://news.nationalgeographic.com/news/2010/11/101118-science-space-full-moon-electric-charge/">Full Moons Get Electrified by Earth's Magnetic "Tail"</a></li><li><a href="http://news.nationalgeographic.com/news/2010/04/100414-moon-magnetosphere-solar-wind/">Mini Magnetic Shield Found on the Moon</a></li><li><a href="http://news.nationalgeographic.com/news/2010/08/100819-science-space-moon-shrinking-scarps-cooling-lunar-orbiter/">The Moon Has Shrunk, and May Still Be Contracting</a></li><li><a href="http://news.nationalgeographic.com/news/2009/07/photogalleries/first-moon-photos-lunar-recon-orbiter/">Moon Pictures: Lunar Orbiter's First Pictures Released</a></li></ul><p><em>—With reporting by Andrew Fazekas</em></p>

Supermoon River

On Saturday the moon (pictured over Lisbon, Portugal's Tagus River) made its closest approach to Earth in 18 years—making the so-called supermoon the biggest full moon in years. (Get the full story of the supermoon.)

The monthly full moon always looks like a big disk, but because its orbit is egg-shaped, there are times when the moon is at perigee—its shortest distance from Earth in the roughly monthlong lunar cycle—or at apogee, its farthest distance from Earth.

Likewise, because the size of the moon's orbit varies slightly, each perigee is not always the same distance away from Earth.

Saturday's supermoon was just 221,566 miles (356,577 kilometers) away from Earth—making the supermoon about 20 percent brighter and 15 percent bigger than a regular full moon, said Anthony Cook, astronomical observer for the Griffith Observatory in Los Angeles.

Before the supermoon, astronomer Geza Gyuk said, "Look for the full moon as it rises above the eastern horizon as the sun sets below the western horizon—it will be a beautiful and inspiring sight."

That's advice a lot of photographers, including National Geographic fans, one of whom contributed this picture, apparently took to heart.

(See more readers' supermoon pictures.)

More Moon Pictures, Facts, and News

—With reporting by Andrew Fazekas

Photograph by Emanuel Lopes, My Shot

Supermoon Pictures: Best Shots of Biggest Full Moon

See our favorite supermoon shots by National Geographic fans and seasoned photographers, who took a shine to the biggest full moon in years.

Read This Next

What drives elephant poaching? It’s not greed
How old are you, really? The answer is written on your face.
The rise of vegan safaris

Go Further

Subscriber Exclusive Content

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet