The Dark Side of the Moon: Paradox of Light and Dark at the Lunar Surface

Author:  Anastasiya Maryukova Pankin

Institution:  University of Toronto

“The moon is at her full, and riding high, floods the calm fields with light. The airs that hover in the summer sky are all asleep tonight.” William C. Bryant

I was walking home late one night, and as I looked up at the sky I felt surrounded by moonlight. The stark beauty of the glowing light took me by surprise and left me in awe. I don’t think much about the moon unless it is in the fall and spring when the moon is rumored to be a cause of madness. For thousands of years, the moon has been associated with mania. Certain folktales claimed that the full moon changes human behavior — causing insomnia, increased anxiety and aggression. According to this superstition, people can become highly disturbed and restless during this lunar phase. In fact, the term ‘lunacy’ comes from the Roman goddess of the moon, Luna, who rode her chariot across the sky at night. As I gazed up at the sky in Toronto, surrounded by the moonlight, I knew that somewhere in the middle of the Pacific Ocean, other moon enthusiasts were witnessing a full lunar eclipse. I experienced a momentous discovery: I wanted to know more about the moon. I wanted to learn what made it so compelling and unique.

The moon’s orbital period is 28 days. When it reaches its closest point to Earth (which only happens about once a month), the moon becomes bigger and brighter, and is known as a full moon. The moon becomes a hot topic only when its egg-shaped orbit is in close proximity to Earth, like it was on October 7, 2014 in the US. Even though there is no scientific evidence that the moon drives people mad, a few moon watchers grow wary when the moon is so close to Earth, remembering the superstitions found in folk legends and popular culture. Scientists refrain from attaching supernatural attributes to the moon and its phases, and they are also wary of mistakenly calling it a super moon. A super moon, essentially, coincides with the full moon, and it refers to the largest apparent size of the lunar disc as seen from earth.

Some astronomers, Neil DeGrasse Tyson in particular, are adamant about drawing the distinction between the terms full moon and super moon. Tyson famously debunked the concept on “StarTalkRadio”, refusing to recruit the super moon to the league of Superman, Super Mario and supernovas.

“I don’t know who first called it a super moon, but if you have a 16-inch pizza, would you call it a super pizza compared to a 15-inch pizza? The super moon is a 16-inch pizza compared with a 15-inch pizza; it is slightly bigger. I ain’t calling it a super moon,” Tyson said.

Tyson’s humorous critique of the super moon downplays the super moon optical illusion, which contributes to the seeming nearness of the moon. Recent research conducted by David A. Paige, a planetary science professor at the University of California, and Andrew Jordan, an astrophysicist at the University of New Hampshire, suggests that our moon is intriguing whether it is full or not.

In the vastness of the solar system, our moon stands apart from over a hundred other moons. The NASA Lunar Reconnaissance Orbiter (LRO) mission, led by Paige, seeks to comprehensively map the entire moon. LRO, a complex robotic machine that gathers high-resolution data about the lunar surface and its environment, launched on June 18, 2009 from Kennedy Space Center. Using the stars to guide its journey, LRO is a complex robotic machine that gathers high-resolution data about the lunar surface and its environment. LRO orbits the moon and Earth.

Covered with circular scars of varying sizes, caused by meteorites and comets crashing into its surface, the moon is an active and fascinating environment. Encapsulated by a dusty rock material, pulverized by these collisions, the moon has no atmosphere and is largely dark, like a sky on a clear night. Paige likens the moon to a planet.

“It goes against the nomenclature used, but where I come from, anything big enough to be round is a planet,” Paige claims.

The Diviner Lunar Radiometer, one of the instruments onboard of LRO, surveys the temperature of the moon’s surface and provides detailed findings about the current thermal environment of the moon.

“Based on Diviner’s richly detailed data, we can characterize many aspects of the moon and its north and south polar regions, which we couldn’t have accomplished in any other way. There are super cold and low temperatures in the south region, which, to our knowledge, are among the lowest that have been measured anywhere in the solar system, including the surface of Pluto,” Paige said.

The presence of these extremely cold and permanently dark places on the moon reveals an extraordinarily diverse environment. There are also rare heat regions, caused by the interaction of sun particles with the surface of the moon. The low temperatures can easily cold-trap water, ice and other volatile compounds. Paige’s mission confirms the existence of cold traps (dark and extremely cold patches that haven’t seen light in a billion or more years) on the moon.

“After decades of speculation, it is safe to assume that the moon houses these cold traps, and the Diviner is currently providing data about their spatial distribution. Getting a look at the first global thermal maps of the moon is a whole new way of seeing the moon”, Paige said.

The moon might be more complex than we thought. Contrary to the old superstition that a full moon makes people crazy, the Reconnaissance Orbiter Mission shows that the moon possesses its own kind of lunacy. Its environment presents a lunar dystopia, a paradox of heat and frigid cold. The craters along the lunar south pole have areas permanently shielded from the sun, harboring deposits of water and ice. The galactic cosmic rays, highly charged and energetic, can penetrate below the lunar surface and send an electric current through the water. The interplay of charged particles and dark airless landscape characterizes the moon’s unique environment.

Jordan and his colleagues have discovered that the extreme cold on the moon could cause a form of sparkiness, akin to a bolt of lightning striking the soil. In a place where no light is thought to have penetrated for a billion years or more, the soil is sent into shock at the hint of a contact with high-energy particles, like the light from the sun. This is called a ‘weathering breakdown’ or a sparking event.

“Sparking events, produced by the trapping of the sun particles at the frigid lunar surface, could explain the foamy appearance of soil, recently detected by the NASA orbiter. The electrons, released from the soil grains by strong electric fields, race through the material so quickly that they vaporize little channels. Repeated sparking disintegrates the soil into smaller particles of distinct minerals. The lunar surface may be far more active than we thought,” Jordan said.

The sparking events contribute to the heat on the moon. These processes are not observed anywhere else in the solar system. They are unique to the moon. These findings can potentially revolutionize how we see the solar system and set the stage for future exploration. Being on the moon will be astounding experience, with astronauts observing daylight and darkness for weeks. The enterprise of lunar studies is not a lost art. These results, provided by LRO’s mission, will reinvigorate interest in the moon as an astronomical entity.

Anastasiya Maryukova Pankin is in her final year of English undergrad at University of Toronto. She enjoys writing poetry as much as she likes writing about cool science stuff.

This piece was developed under the guidance of Science Writing Mentor Susan Swanberg.



  1. Electric Sparks May Alter Evolution of Lunar Soil
  2. The Moon Comes Around Again
  3. Surface albedo spectral properties of geologically interesting areas on Titan
  4. NASA’s LRO Leads the Way to the Moon and Beyond!