May 2016 Newsletter

In this Clergy Letter Project update, you’ll find the following five items:

  1. Good News from the United Methodist Church’s General Conference;
  2. Astrobiology News for May 2016:  Walking on Other Worlds;
  3. Good News from Texas;
  4. Free Resource for Evolution Weekend; and
  5. Tree Hugging on Earth Day.

1.  Good News from the United Methodist Church’s General Conference

I’m delighted to announce that The Clergy Letter Project was again endorsed by the United Methodist Church at its 2016 General Conference. The United Methodist Church’s original endorsement occurred in 2008 and was good for eight years. While many people deserve credit for the successful effort to renew the endorsement, none were more instrumental than Clergy Letter Project scientific consultant Gary Sherman.

The resolution that was adopted with a 63 percent approval rating reads as follows: “The United Methodist Church endorses The Clergy Letter Project and its reconciliatory programs between religion and science, and urges United Methodist clergy to participate.”

This resolution will remain in the Church’s Book of Resolutions for an additional eight years unless it is removed or modified at the 2020 General Conference.


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2.  Astrobiology News for May 2016:  Walking on Other Worlds

In this month’s Astrobiology News, Clergy Letter Project consultant and Adler Planetarium astronomer Grace Wolf-Chase melds science and science fiction in her discussion of gravity beyond Earth.

For as long as I can remember, I wanted to be an Astronomer. Three things motivated this desire – science fiction, the space program, and, since I grew up about 10 miles from Manhattan, visiting the Hayden Planetarium in NYC. I recall checking my weight on other worlds using a set of old mechanical scales and wondering what it would be like to move about on the Moon, where I’d weigh only 1/6 of my Earth weight. Not long after, I remember watching the Apollo astronauts and thinking how amazing it would be to bounce across the surface of another world like that!

In most science fiction movies, human beings appear to navigate around on all sorts of planetary surfaces exactly as they would on the Earth. Of course, depicting how people would walk on planets with vastly different surface gravities is difficult to implement, both technically and financially. As it turns out, though, walking around on different alien planets might not be so different from walking around on Earth!(1) Curiously, our Solar System contains five worlds with very different environments that have approximately the same surface gravity, and therefore your weight wouldn’t change much from world to world. Why is this so?

The surface gravity of a planet increases with a planet’s mass and decreases with the square of its radius. This means that if planet A and planet B are the same size, but planet B has twice planet A’s mass, planet B’s surface gravity will be twice as large; however, if planet A and planet B have the same mass, but planet B’s radius is twice as large, planet B’s surface gravity will only be one-fourth that of planet A’s. It turns out that for very large gaseous planets (like Jupiter and the “super-Jupiter” class of exoplanets), the surface gravity just increases with the mass of the planet because the size of the planet doesn’t change much in this range. The small rocky or icy worlds (e.g., small Solar System bodies, dwarf planets, and worlds like Mercury and Mars) do get bigger as the mass grows, but not enough to offset the increase in mass and thus surface gravity.

Between these two extremes is a rather large transition zone, where the mass and size of a planet grow in such a way that the surface gravity doesn’t change much. Earth lies in this zone, as do Venus, Uranus, Neptune, Saturn, and a host of exoplanets that also include some of the worlds currently known as “super-Earths.” (Of course, you couldn’t actually walk on the surface of a gaseous planet like Saturn!) This similarity in surface gravity is surprising, because these worlds are very different in mass, composition, and physical structures. It’s not yet clear how to connect “allowable” masses and sizes of planets, but as the database of known worlds increases, the observed properties of these worlds will help place useful constraints on models of how planets form.

In the meantime, exoplanet discoveries indicate that it is not just a coincidence that five worlds in our Solar System have nearly the same surface gravity, even though we don’t understand yet why the “transition zone” exists. The article cited in the footnote concludes with, “Therefore, if while viewing The Force Awakens the reader sees Harrison Ford walking on Takodana as if he were strolling down Hollywood Boulevard, do not be too critical. After all, this may not be so wrong.”

Until next month,


Grace Wolf-Chase, Ph.D. (

1.  Ballesteros, F. J. and Luque, B. 2016, Walking on Exoplanets: Is Star Wars Right?, Astrobiology, Vol. 16, No. 5 (DOI: 10.1089/ast.2016.1475)

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3.  Good News from Texas

In a somewhat surprising election result, Mary Lou Bruner was defeated in her bid for a seat on the Texas State Board of Education. As you likely know, the Texas Board plays a powerful role in setting educational policy in the state with ramifications throughout the rest of the United States.

Just how surprising this result was can be seen in the opening sentence from an article about the election in The Guardian which appeared on the morning of election day: “The question of how extreme is too extreme for Texas Republican voters may be answered on Tuesday evening, when voters are expected to favor a woman who believes that Barack Obama was a drug-addicted male prostitute, in an election that could put her on the brink of one of the most influential positions in the state’s education system.” The article goes on the mention other truly troubling positions promoted by Bruner, including that pre-kindergarten is a federal plot to confuse children about their sexuality, that the United States should ban Islam and that climate change is a hoax invented by Karl Marx. The piece also notes that Bruner believes “that humans and dinosaurs walked Earth simultaneously, and dinosaurs died out because only babies were carried on the Ark, so they were too young to reproduce on a barren planet after the flood.”

Bruner lost the election to fellow Republican Keven Ellis, a school board president from Lufkin, TX. I think it is fair to say that the Texas Freedom Network, a good friend of The Clergy Letter Project, played a significant role in the outcome of the election. The Guardian’s article summarizing the results of the election is well worth reading.


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4.  Free Resource for Evolution Weekend

The Reverend Kurt Huber, regular participant in Evolution Weekend, brought a free resource to my attention that I want to share with you. He is currently using In the Beginning: A Video Curriculum Exploring the Catechism of Creation with his parishioners and he speaks highly of it. You can order this free video by going here.

Since this curriculum might offer an easy and productive way to organize an Evolution Weekend event, why don’t you sign up to participate now:

_____ YES! Please sign us up to participate in Evolution Weekend 2017 – 10-12 February 2017

Name of Congregation:
City, State:
My Name:

And please send me information about resources that you think others will find helpful.



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5.  Tree Hugging on Earth Day

Pastor Marty Toepke-Floyd shared an essay he wrote for his local newspaper in Redfield, South Dakota with me. Because I think it ties together many issues that are central to the efforts of The Clergy Letter Project, I’m making it available to you. I hope you enjoy it!

Please don’t be shy about sharing your writings with me. I’m confident that many members and friends of The Clergy Letter Project would enjoy reading them.


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As I close this month’s Newsletter, let me remind you that if you’re planning to attend the PCUSA General Assembly in Portland this coming June, I hope you’ll be able to join me for a discussion of The Clergy Letter Project. I’m scheduled to be at the The Kirbas Institute booth on Monday, 20 June from 11:30 am – 1 pm. I hope to see you there!

Our ranks continue to expand. Well over 14,000 clergy from the United States have signed one of our Clergy Letters with many more from around the globe participating in Evolution Weekend events. Please take just a moment to do two things. First, forward this Newsletter to a colleague or two and ask them to add their voices to those promoting a deep and meaningful understanding between religion and science. They can add their signature to a Clergy Letter simply by dropping me a note at Second, if you’re in a position to do so, please sign up now to participate in Evolution Weekend 2017. As always, thank you for your continued support. Together we are making a difference.


Michael Zimmerman
Founder and Executive Director
The Clergy Letter Project