Traveling to 'the Dark Side'

The dark side of the moon has captured imaginations since we first stepped foot there over 40 years ago. From Pink Floyd to the recent Transformers movie, popular culture has theorized what is on the side of the moon that is in perpetual darkness. So, what is the dark side of the moon? Are there really alien robots on the other half of the moon, or have we shed a little more light on the subject?

Well, it turns out that there actually isn’t a “dark side.” Like the Earth, the moon has both a day and a night. It is better to say that the moon has a “day side” and a “night side” than a “dark side.” Sometimes, the side facing the Earth is the day side, and other times it is the night side: this is why we observe moon phases.  Both sides of the moon receive sunlight.


Caption: Phases of the moon.


The reason it seems that only half of the moon receives sunlight is because the Earth only views half of the moon. It is more accurate to say that the moon has a near side and a far side. The near side is always facing Earth and the far side is always facing away, because the moon revolves around the Earth at the same rate that it rotates on its own axis. It takes 29 days for the moon to rotate around its axis, and it also takes 29 days for the moon to orbit around the Earth. If the moon did not rotate, or if it orbited slower around the Earth, then we would be able to see the other side of the moon, but because these rotations happen at the same rate we always see the same side. This term is known as synchronous rotation.


Caption: Synchronous rotation.
Credit: Wikipedia

While only one side of the moon faces Earth, we still have an idea of what the far side looks like thanks to NASA’s Lunar Reconnaissance Orbiter Camera, or LROC, Wide Angle Camera, or WAC. The LROC was the first space craft to take high resolution photos of the far side of the moon last March, finally giving scientists a complete picture of the moon.


Caption: The lunar far side, seen by the LROC WAC.
Credit: NASA/Goddard/Arizona State University

There may not be aliens on the far side of the moon, but there are still many questions about it that we are still in the dark about, like why does the crust appear thicker on the far side? As NASA continues to explore the far side of the moon, people will no doubt continue to be fascinated by the “dark” side and continue to look for answers to illuminate its mystery.

NASA Catches First Glimpse of This Year's Perseid Meteor Shower

On the night of July 26, allsky cameras of the NASA fireball network detected three Perseid meteors in the skies above Tennessee and Alabama. The first seen by the cameras this year, these meteors are the “advance guard” of the Perseid meteor shower, which will peak on the night of Aug. 12.

A bright Perseid meteor crosses the sky over Huntsville, Ala. on July 26, 2011
Credit: NASA/MSFC/Meteoroid Environment Office

Want to watch the Perseids with NASA astronomy experts? Make plans to join astronomer Bill Cooke and his team from NASA’s Marshall Space Flight Center for an “up all night” Web chat on the night of Aug. 12 and into the early morning of Aug. 13. You can ask your questions and also view a live Ustream view of the Perseids in the skies over Huntsville, Ala.

If you or another astronomy group is planning a live Web view of the Perseids, please leave us a comment and let us know — we’ll feature a link to your live Perseids Web stream!

More information about the chat is located here:


NASA Book Available For Visually Impaired To Learn About Moon

NASA has released a new book for visually impaired people to experience the wonders of the moon. Called “Getting a Feel for Lunar Craters,” the 17-page book features Braille and tactile diagrams of the lunar surface, craters and peaks.

The book was created and funded by NASA’s Lunar Science Institute, or NLSI, at Moffett Field, Calif. The author is David Hurd, a space science professor at Edinboro University of Pennsylvania in Edinboro,PA.

“This book is one giant step for humankind, making lunar science,” NLSI Director Yvonne Pendleton said. “NASA is committed to the development of resources to bring lunar science into the world of those who cannot see.”

To obtain a free copy of “Getting a Feel for Lunar Craters,” visit:

 NLSI is a virtual organization that enables collaborative, interdisciplinary research in support of NASA lunar science programs.The institute uses technology to bring scientists together around the world and comprises competitively selected U.S. teams and several international partners. NASA’s Science Mission Directorate and the Exploration Systems Mission Directorate in Washington fund NLSI, which is managed by NASA’s Ames Research Center at Moffett Field, Calif. For more information about the NLSI, visit:

Enjoy July's Full Moon

Take a break Friday night, step outside and gaze up at the full moon. July 15 is the full moon for this month — perhaps most commonly nicknamed the Buck Moon.


Image credit/copyright to Synapped. Used with permission, all rights reserved.
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According to many Native American traditions, July is normally the month when the new antlers of buck deer emerge from their foreheads in coatings of velvety fur — hence one of the names for the full moon.

The full moon in July also is called the Thunder Moon because of the frequency of thunderstorms during this hot, dry month.

Yet another name for the seventh full moon of the calendar year is the Hay Moon — likely no surprise to anyone living on a farm, who may have spent recent weeks cutting, baling and storing hay for the coming winter. And for those of us who suffer from summer allergies, the Hay Moon may be the most familiar moon of all.