What the Moon Can Teach Us About Science

“I still say, ‘Shoot for the moon; you might get there.’”
Buzz Aldrin

Last month on January 21, 2019, I stood in the snow in below freezing temperature to photograph the lunar eclipse. 

January 2019 Lunar eclipse, photography by PJ Bennett
January 2019 Lunar eclipse, photography by PJ Bennett

Almost as much as the lunar eclipse itself, I enjoy the discussion leading up to the eclipse.  The news seemed to focus on the name of the eclipse, the super blood wolf moon eclipse.  I will admit it’s a great name and each part of it means something.  However, what if I told you that all total lunar eclipses have names.

A total lunar eclipse can only occur when there is a full moon.  The full moon is essential because every month’s full moon has a name.  February’s full moon (Feb 19, 2019) is the full snow moon.  February is also a super moon the second of three super moons in a row March will also be a super moon.  So, using the pattern from January Februaries full moon is a full super snow moon.

February 2019 Full Super Snow Moon, photograph By PJ Bennett.
February 2019 Full Super Snow Moon, photograph By PJ Bennett.

Our fascination with eclipses is interesting.  After all its not like they surprise us anymore, for instance, there will be a total Lunar eclipse in Denver on Feb 13, 2101, with its maximum at 7:46:33 pm.  The precision of this prediction is, of course, dependent on the model of the solar system and our observations of the positions of the plants. I suspect our fascination with eclipses has to do with the fact that there are very few things that let us observe the workings of the solar system.

Regardless of why its fascinating astronomy is an excellent way to both increase interest in the STEM fields and teach research methodologies.  Using astronomy to promote an interest in STEM is rather simple.  Anytime there is an astronomical event it gets covered in all the media.  Schools and organizations that promote STEM education should hold viewing parties.  In addition to helping people get a good view of the celestial event having experts present to talk about the event and science, in general, helps stir interest in STEM fields.

While I have seen some schools, observatories, and planetariums hold viewing parties it has defiantly not been all or most schools.  Additionally, these viewing parties would make a great cornerstone for a larger event that involved multiple STEM fields.  Helping participants understand that all the STEM fields are related and accessible will only help improve interest in the STEM disciplines.

Beyond promoting general interest in STEM, the history of astronomy makes a great teaching tool for the scientific method.  Anytime there is an eclipse especially a total solar eclipse someone always talks about how terrified this event must have been for early peoples.  We take for granted that we can predict eclipses.

In the media, we tie our ability to predict eclipses to our understanding of the plant’s motion around the sun which was first formally proposed by Copernicus in the 1543 publication of On the Revolutions of the Heavenly Spheres.  The only significant flaw with Copernicus’s model is that he thought the orbits had to be perfect circles.

Before Copernicus, the astronomic model of the solar system was dominated by the Ptolemaic model which had the earth at the center of the solar system (the center of the Universe).  This model lasted for about 1400 years.  However, even with incorrect or incomplete models of the solar system, the ability to predict eclipses has existed for at least 2000 years probably longer.  For instance, the Dresden Codex is a Mayan book written sometime in the 13th or 14th century; the authors based the codex on a Mayan book several centuries older.  The codex contains calculations on astronomy including accurate predictions of eclipses for both the sun and the moon. 

Six sheets of the Dresden Codex (pp. 55-59, 74) depicting eclipses, multiplication tables and the flood. Auther is unknown, This work is in the US public domain.
Six sheets of the Dresden Codex (pp. 55-59, 74) depicting eclipses, multiplication tables and the flood. Author is unknown, This work is in the US public domain.

Using the information in the Dresden codex anthropologists Harvey and Victoria Bricker were able to predict the Central American solar eclipse of July 11, 1991, to within a day in 1983 (If you’re interested the full paper is here.) Considering that we must convert the Mayan calendar to match our calendar that is amazingly accurate for something written hundreds of years before Copernicus published his model of the solar system.

We also know that the Mesopotamians and ancient Greeks predicted eclipses perhaps as far back as 2000 years. (Griggs, M.B. (2017, August 18). We’ve been predicting eclipses for over 2000 years. Here’s how. Retrieved from https://www.popsci.com/people-have-been-able-to-predict-eclipses-for-really-long-time-heres-how) If the correct understanding of the motion of the plants in the solar system is a relatively new thing how did older cultures predict eclipses and how does this help explain why the scientific method is essential?

Older cultures were able to predict eclipses because they follow a repeating cycle called the Saros Cycle, which is approximately 223 months long.  If a civilization lived long enough and its records were accurate enough deriving the Saros cycle is possible. Information on the periodicity of celestial events and observations of the night sky let individuals like Aristotle and Ptolemy developed the first models of the solar system with the earth at its center, also known as a geocentric model.

The Solar System according to the geocentric model of Claudius Ptolemaeus. By Andreas Cellarius. This work is in the US Public domain.
The Solar System according to the geocentric model of Claudius Ptolemaeus. By Andreas Cellarius. This work is in the US Public domain.

So how did this Ptolemaic model and its decedents last for almost one and a half millennia? The biggest reason is that the model fits all the relevant data and for most of this period the scientific method as we know it didn’t exist.

If the modern scientific method had been present at the time of Ptolemy, his geocentric model would have been a hypothesis, a prediction based on observation.  Again, using the scientific method astronomers would have tested the model by either trying to disprove it or by trying to disprove an alternative hypothesis.  Nowadays we understand that the best experiments are the ones designed to either disprove a hypothesis or distinguish between competing hypothesis. At the time of Ptolemy, astronomers did not challenge the model because it matched the observations and social beliefs.

Using the models of planetary motion from Ptolemy to Kepler makes an excellent background for discussions of the scientific method.  For the average person, all three models appeared to work and could predict celestial events.  Because they lacked our modern approach to science, several of these models persisted much longer then they could have.  Linking education to current events that capture people’s attention and excite them is one of the best ways to motivate a student. Next time a science-related story catches peoples attention think about how you might use it for education or motivation.

Thanks for Listing to My Musings
The Teaching Cyborg

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