What is the Rare Earth Hypothesis?
A Controversial Concept
The Rare Earth Hypothesis is based on the theory created by scientists, Peter D. Ward and colleague Donald Brownlee. Brownlee, an astronomer and astrobiologist along with Ward, a paleontologist and geologist, share the summation that while the universe is vast in size, its naturally hostile nature makes the possibility of life on planets other than Earth, or anywhere else in the universe, a statistical improbability therefore making our own planet a “rarity”. Although challenged by other ideas such as the Copernican Principle, many feel this simple proposition alone supports the Rare Earth Hypothesis.
In their book, “Rare Earth: Why Complex Life is Uncommon in the Universe”, Ward and Brownlee ask the sometimes controversial and argued question, “What is needed to create life?” Rare Earth offers the conclusion that the Earth, in its assumed orphaned birth, is rare and by way of this, so must be any complex organism created from it.
The Rare Earth Hypothesis uses common facts relating to celestial events proven to have taken place millions of years ago to form the basis for its theory. Surmising that because the Earth holds the ingredients for the formation of simple life forms since its earliest recorded age, and accepting that common fact has proven other researched or explored planets to not be as fit for the growth of complex organisms, many feel The Rare Earth Hypothesis can be grounded in factual evidence and not based solely on theory, opinion or conjecture alone.
Basis in Facts
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Ward and Brownlee use several common facts to bolster their Rare Earth Hypothesis position.
• While no other celestial body has been proven to have had sustained water available, the Earth is made up of nearly all water which covers over 70% of the Earth’s surface.
• While no other celestial body has a radiating star sufficiently close enough to its rotational balance, Earth does.
• While other celestial bodies are positioned either too near a heat radiating source (too hot) or too far (too cold), Earth’s position, being third from the Sun, makes its climate system ideal.
• While the atmospheres of other celestial bodies are fraught with deadly vapors and gasses, Earth’s atmosphere of nitrogen, oxygen and minor yet important percentages of carbon dioxide, ozone and water vapor, give our planet the universally rare benefit of a clean air source for new life growth and sustainment.
According to the Rare Earth Hypothesis, the above stated conditions, along with the circumstances of Earth’s gravitational rotation, size and impact from general planetary debris, give Earth a relative advantage in complex organism development over other planetary bodies. Also considered in the Rare Earth Hypothesis is Earth’s general placement and distance between other planetary bodies. Earth’s position, between Venus and Mars, affords its surface temperature to remain markedly controlled changing only according to seasonal alignment with the Sun.
Comparative Ideas
Ward and Brownlee, with the Rare Earth Hypothesis, seek to challenge other published or stated hypotheses like The Copernican Principal. Supported by Carl Sagan, and named by Hermann Bondi after famed mathematician and astronomer, Nicolaus Copernicus, The Copernican Principle would suggest that the planet Earth is not a rarity at all and is at no more of a celestial advantage than other planets. But with the use of mathematical statistics aimed at understanding Earth’s early formation of available resources for the growth of complex organisms, and taking into account the absence of other events to which this would apply in the general universe, The Rare Earth Hypothesis presents a clearly evidentiary case in support of the theory.
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