Tuesday, May 28, 2019

The Magnificent Moon


The earth is unique in our solar system, being the only planet that has one single large moon. Over the last few decades scientists have realized that our moon plays a significant role in order for the earth to support complex life forms. The gravitational pull of the moon on the earth is responsible for high and low ocean tides, which bring nutrients to tidal flood zones and allow for a diverse and thriving ecosystem near coastal regions. Tides also play a role in a global temperate climate because they affect ocean currents that move water around the globe.

Perhaps the most important feature of the earth-moon system is the relatively large gravitational pull of the moon, which stabilizes the tilt axis of the earth. The earth rotates around an axis that is tilted about twenty-three degrees from a line drawn perpendicular to the plane of its orbit. Because the earth's axis is tilted, we have various seasons: summer, spring, winter, and fall. When the earth’s orbit is on one side of the sun and it is tilted in such a way that the northern hemisphere gets direct sunlight, then it is summer in the northern hemisphere and winter in the southern hemisphere. When the earth is on the other side of the sun so its tilt gives direct sunlight to the southern hemisphere the seasons are reversed.

As the earth rotates it wobbles a little, like a top spinning on a table. If we did not have a single large moon that wobble would be much greater and the tilt of the earth would fluctuate over many different angles rather than be relatively constant at about twenty-three degrees. The wobble would be so great that at times our current north and south poles might face straight toward the sun or away from the sun. This would mean that the north and south poles would not be consistently cold, causing ice to melt and leading to some of the same kind of catastrophic consequences proposed in the worst-case scenarios of global warming. In general, the climate on the earth would fluctuate wildly and would not ever reach a nice stable equilibrium. Without our single large moon, it is unlikely that any complex life would exist on the earth.

The story of how we got our single large moon is dramatic and fascinating. Our solar system began to form about 4.6 billion years ago when a dense cloud of gas and fine dust, attracted by gravity, coalesced to form our sun. Some of the dust and gas not captured by the sun began to form the various planets. Planets and other objects in the inner solar system, like the earth, were mostly dry while objects farther out had more carbonaceous elements (elements with carbon and other related elements necessary for life like water). The earth substantially formed as gravitational attraction brought many smaller rocks and asteroids together sometime about 11 million years after the solar system began to form. It seems that this early earth did not have enough water or other elements necessary for life to exist.

The circumstances that conspired in the very early history of the earth, which led to us having our current moon and the elements necessary for life, seem to be both opportune and unlikely. Late in the earth's formation period, sometime about 30 million to 110 million years after the solar system began to form, a large proto-planetary object about the size of Mars crashed into the earth in a violent collision. The collision had to occur in such a way that material from the earth and this planetary object, sometimes called Theia, intermixed and ultimately re-formed into two different objects, the moon and the earth, both containing material brought by Theia. There has been much discussion of whether Theia had originally formed in the inner solar system or in the outer solar system. However, a recent paper just published in the May edition of Nature Astronomy by scientists at the University of M√ľnster concludes that Theia had originally formed in the outer solar system and when it collided with the earth it carried with it most of the water that is currently on the earth.1

This adds another item to the list of those things of vital importance that the moon brings to the earth. It stabilizes the tilt of the earth, it brings replenishing tides to coastal regions, and now it seems that it is the source of the vast majority of the water on the earth.

As a Christian I use the Bible as the primary source for understanding what God is like. The Bible proclaims that God accomplishes his purposes through the normal laws of nature as well as through miracles, but also through non-miraculous, but unlikely circumstances (as I described in this blog post). For instance, the Bible describes an incident when Phillip, a disciple of Jesus, was led to a desert place where he just "happened" to encounter an Ethiopian official who "happened" to be reading about the Messiah from the book of Isaiah and wanted someone to explain what it meant, giving Phillip the opportunity to tell the Ethiopian about Jesus. An earthquake just happened to occur at the time Jesus was crucified indicating that his death was something consequential. The Apostle Paul experienced a series of unlikely events that ultimately led him to the capital city of Rome where he was able to present a case for Jesus before the Roman officials.

Until now the scientific evidence indicated that we have our magnificent moon only because a large planetary object with the just the right mass hit the earth at the right angle at the right speed at the right time in early in the earth's history. This newly published paper concludes that this unlikely collision also brought water to the ancient earth. Nearly 4.5 billion years ago, the providential hand of God was orchestrating events as he prepared a place that we could live, thrive, and ultimatley have a relationship with our Creator.

1Gerrit Budde, Christoph Burkhardt, Thorsten Kleine. "Molybdenum isotopic evidence for the late accretion of outer Solar System material to Earth." Nature Astronomy, 2019.

5 comments:

  1. I found out about this blog from another blog.
    I an a creationist(YEC) who is confident god described how he created stuff.
    the moon , he said, was created on creation week. so only 6000 years old.
    This stuff about it evolving from dust caught in orbits etc is just human speculation. or rather what else could they say to explain it.
    Its just guessing tom me with no proof.
    The one thing a creationist might pick up on the moon is the spectrum of impacts on it. If they are not random around the moon it would suggest there was not these billions, millions, of years. As unlikely for a concentration .I think i read there was a concentration on one side of the moon.
    The concentration would suggest impacts coming almost all at once. From some event indeed like earths impacts.

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    1. Hi Robert,

      Welcome to the blog.
      I, too, am a creationist who is confident God described how he created stuff and believes what God said about the creation week. I take the Bible seriously and believe what it says is true. In fact, I take the Bible so seriously that I have spent thousands of hours studying what the Bible says by looking at the original language and culture in which it is written.

      In English, the word "day" can mean a long period of time like when I say "In George Washington's day the colonists fought the revolutionary war." In English, "evening" and "morning" (or "dawn" and "twilight") can mean beginning and ending like when I say "the dawn of a new age" or "the twilight of someone's life." In Psalm 90, Moses uses the words evening and morning to mean metaphorically the beginning and ending. If these words can mean "a long period of time" and "beginning" and "ending" in English, will you please tell me why you do not think they can mean those same things in Hebrew in Genesis 1? Have you read what scholars who actually study the ancient Hebrew language and culture say about these words?

      The many craters on one side of the moon come from the fact that one side of the moon always points away from the earth, so the earth shields one side of the moon from impacts but the other side gets many more impacts. Regardless of the age of the moon, the far side will get more impacts. The concentration suggests that the earth shields one side of the moon but not the other.

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  2. Thinking about this post and all the others you have detailed and in particular the competing proposals among both scientists and Christian communities of thought, have you considered how any particular choices favored are consistent with the Christian belief that EVERYTHING over time must result in bringing greater glory to God, as I belief the Word makes clear. A simple example might be in what way does old earth creationism more completely enhance God;s glory relative to say young earth creationism. Would you conclude that this universe and everything that has occurred in it's history has in some way brought the greatest possible glory to God or will in the course of time as His will is worked out.

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    1. Great thought Keith. Yes, I agree with you (and Scripture) that all creation and created things will ultimately bring glory to God. To me OEC brings much more glory to God than YEC because within the context of OEC, we as humans can explore and understand the universe, including up to its very origin. God, then, makes himself knowable through creation because an exploration of nature gives real truths about God, his character, and his care for humanity.

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  3. Michael,
    I offer many amens for your thoughtful responses to Robert and Keith. God is certainly more glorified when Christians speak truthfully about His creation with the evidence for old earth creation. God's character is ridiculed by the division in the Church since 1961 with the rise of young earth creationism, when the Bible itself does not inform us when Genesis 1:1 occured.

    Robert and Keith,
    Please get a copy of Professor Strauss's book, The Creator Revealed. It is written for the non-scientist, explaining how the Big Bang and Genesis 1 fit together so well.

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