A lone astronaut standing facing away from the camera dressed in full space suit with backpack, stands still looking towards a distant planet Earth. The sun illuminates a side of Earth and hundreds of stars are visible in deep space.
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How well do you know Earth’s moon? CWRU faculty share their expertise

Though decades have passed since the Space Race took place, Earth’s moon remains the only place beyond our planet where humans have set foot. As the brightest and largest object in our night sky, the moon causes tides that create a rhythm—one that has guided humans for thousands of years. 

The moon also inspires curiosity that leads to careers in the aerospace field, as has been the case for numerous Case Western Reserve University alumni who work at the National Aeronautics and Space Administration (NASA). And, thanks to contemporary lore, it even gets blamed for strange human behavior.

Today (July 20) is National Moon Day, which commemorates the Apollo 11 spaceflight that first landed humans on the moon in 1969. To learn more about Earth’s only natural satellite, The Daily caught up with professors from CWRU’s Departments of Physics, Astronomy, and Earth, Environmental and Planetary Sciences

Read on to gain their insights into Earth’s most constant companion. 

1. The Moon is covered with mountains that are (just barely) invisible to the naked eye.

Galileo was the first to report craters and moons observed through a telescope. His reports were somewhat controversial at the time since they implied that the moon (a “celestial” and therefore “heavenly” body) had “terrestrial” features similar to those found on the Earth. Today, these features can be easily seen by viewing the moon through a small telescope or even a pair of binoculars.  

Corbin Covault, Professor, Department of Physics

2. A full moon always rises in the east either just before or just after sunset in the west, and it sets in the west just before or just after sunrise in the east.

Put another way: The full moon and the rising/setting sun can be seen together only when they are near the horizon and on opposite sides of the sky. This is an unavoidable consequence of the geometry between the Earth, moon, and sun geometry—and the fact that the full moon is “full”—because the sun completely illuminates the side of the moon facing the observer.

— Corbin Covault, Professor, Department of Physics

3. The moon has places of eternal light and permanent darkness.

Because of the tilt of the moon’s axis and the fact that there are deep holes from impact craters and mountains that surround them, there are places that always receive light from the sun or none at all. In some impact craters very close to the north and south poles of the moon there are areas that are permanently in shadow; the sun’s rays never reach them. These areas are exceptionally cold and even hold some water ice, likely delivered to the moon by comets. There are also a few mountain peaks that poke above the terrain enough near the poles that they constantly receive sunlight.  

Steven A. Hauck, II, Professor, Department of Earth, Environmental and Planetary Sciences

4. The moon has quakes.

Like earthquakes here on Earth, the moon has quakes resulting from quick shifts of rocks along faults. On July 20, 1969, astronauts Neil Armstrong and Buzz Aldrin placed the first seismometers on another planetary body so that scientists could record these quakes. Seismometers left on the moon operated until 1977 and recorded moonquakes that have helped scientists determine the internal layering and history of the Moon.

— Steven A. Hauck, II, Professor, Department of Earth, Environmental and Planetary Sciences

5. The moon is the source of some of the meteorites found on Earth.  

Pieces of the moon have been returned to Earth by astronauts during the Apollo program and by robotic spacecraft from the former Soviet Union and most recently China. However, humans, including as part of the U.S. Antarctic Search for Meteorites (ANSMET) program that was led by Ralph Harvey at Case Western Reserve University, have collected other pieces of the moon in the form of meteorites, which are rocks that fell to the Earth from space. These rocks were launched off of the moon during impact events when larger asteroids hit the moon in the past. These lunar meteorites permit scientists to study how the moon was formed and has changed with time.

Steven A. Hauck, II, Professor, Department of Earth, Environmental and Planetary Sciences

6. The moon is Earth’s identical chemical twin.

Unlike other solar system objects we have samples of, including Mars and many different asteroids, the moon is Earth’s chemical twin. Their isotopic composition is almost identical for every element that has been analyzed. The prevailing hypothesis is that the moon formed, early in the history of the solar system, after a large collision between the proto-Earth and a roughly Mars-sized planetary body. 

James Van Orman, Professor, Department of Earth, Environmental and Planetary Sciences

7. There is no perpetually “dark side of the moon.”

There is only a “far side of the moon,” because the moon’s rotation and orbit are locked by tidal forces, such that the same side of the moon always faces us. 

John Ruhl, Connecticut Professor, Department of Physics

8. It takes light about 1.3 seconds to get to the moon from Earth. 

The Apollo astronauts left retroreflectors on the moon over 50 years ago that are still used today to make precise measurements of the moon’s orbit, by timing pulses of light making the round trip. 

— John Ruhl, Connecticut Professor, Department of Physics

9. We think of the moon as bright white, but it actually absorbs 93% of the sunlight that hits it. 

In reality, the surface of the moon is nearly as dark as fresh asphalt.  

Benjamin Monreal, Agnar Pytte Associate Professor, Department of Physics

10. Tidal friction is slowing down the rotation rate of the Earth.

This process adds about 2.3 milliseconds to the length of each day every century.

Chris Mihos, Professor, Department of  Astronomy

11. The first words on the moon by the second astronaut to set foot there (Buzz Aldrin) were, “Neil, do you have the keys”?  

I thought it was a lie when I first heard that, but I’ve watched the original video and he definitely said it. Fits his character too.

Ralph Harvey, Professor, Department of Earth, Environmental and Planetary Sciences

12. The lunar astronauts stumbled and fell over and over and over again. 

They really had trouble adapting to walking in low gravity and found a kangaroo-like hop was the best they could do. In the end, the cart from Apollo 14 and the buggy from later missions had as much to do with limiting the risk of damaging the suits (from astronauts stumbling) as it did with increasing mobility. The public didn’t get to see that stumbling around much until the full, unedited videos were released in the late ‘80s, because NASA didn’t want to soil the image of the astronauts (pun intended). 

— Ralph Harvey, Professor, Department of Earth, Environmental and Planetary Sciences

13. The astronauts were filthy with lunar dust when they got back in the Lunar Excursion Module (LEM) and claimed it smelled sharp and mineral-like, resembling gunpowder.

It was also gritty and abrasive and stuck strongly to suit fabric, the fabric insulation on the walls, etc. (it was both angularly and generally positively-charged from solar wind implantation). The astronauts and their gear were completely covered in it and large amounts were released the command module door was opened after splashdown.  

That made the quarantine the astronauts were held in immediately afterwards something of a joke. But at least they kept up appearances and of course the soil (like the rest of the moon) was utterly sterile. 

— Ralph Harvey, Professor, Department of Earth, Environmental and Planetary Sciences

14. The moon helps stabilize the Earth’s spin axis, leading to a more stable climate. 

The tides, which are mostly driven by the moon, may well have played an important role in the origin and evolution of life, and almost certainly in its emergence from the ocean onto land.

Glenn Starkman, Professor, Department of Physics