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How Many Are There?

Earths, That Is

How many earths ARE there. It is impossible to tell. There may be billions. There may be a few. There may be one.

It all depends on a host of factors. (SETTI, The search for extraterristral intelligence, listening for radio signals in our galaxy for the past 40 years has heard nothing.) If there is life like ours, then perhaps we would hear a radio signal with clear information in it.

Or, we can look through telescopes, but that dosen’t reveal a whole lot. It all depends on how much needs to be just right. It is possible there is only one, or that there are billions. My own intuition says there are a ”few.” But perhaps the number doesn’t matter. What matters is what the earth does for us, and that is how global warming brings up the greatest question there is.

As best as we know life originated on the earth and evolved over millions of years to create homo sapiens. That is us.

So “us” is asking the question what is LIFE (caps intentional). This is the place where something throws me, because I have to answer the question about Life, and hardly anyone talks about it even the physicists who talk about theories of everything. As far as I know they talk about the four laws of physics and leave it at that. Then I start asking what is it that is so special about being alive and that blows my mind.

Make To Order And Throw Away the Mold

It seems impossible that one planet would be perfectly made.

from the article: Earth, Just Right For Life

The Rare Earth Hypothesis: Why Complex Life Is Uncommon in the Universe.’


“... Earth...boasts several features that make it ‘just right’


The right ingredients: A planet needs liquid water, an energy source and chemical building blocks like carbon, oxygen, hydrogen and nitrogen for the life forms we're familiar with to thrive.

The right crust:Gas giants and molten worlds need not apply. Luckily, Earth possesses the suitable distribution of elements to ensure a hot metallic core and a rocky mantle.

The right temperature: The necessity for liquid water also means that planetary temperatures must permit the substance to retain its liquid form in some regions.

The right moon: Our large moon ensures climate stability by minimizing changes in planetary tilt. If our planet didn't have a tilt, it wouldn't have seasons. Likewise, a severe tilt would result in extreme seasons.

The right star: The sun provides Earth with the energy for life and is thankfully rather stable. Imagine baking a pot roast with an oven that might suddenly surge in temperature, die or explode. It wouldn't work for your pot roast, and it certainly wouldn't work for life.

The right core: Earth's solid inner core and liquid outer core play crucial roles in protecting life from deadly solar radiation. Differences in temperature and composition in the two core regions drive this powerful dynamo, emitting Earth's protective electromagnetic field.

The right neighbors: Jupiter shields Earth from constant stellar bombardment. Without the gas giant in the neighborhood, scientists predict that Earth would endure 10,000 times as many asteroid and comet strikes [source: Villard].

In short, Earth contains all the ingredients and environmental necessities for life to emerge, plus the relative safety for it to evolve unmolested for hundreds of millions of years on end.

How common are these combinations in the universe?

Astronomers have now discovered thousands of planets. Some obviously are not suitable for higher forms of life. Others, it is impossible to tell. As a guess, if there is a 1% chance of each of seven requirements, the probability of a planet possessing these characteristics is 0.017 or 10-9 which is one in a billion.

A deeper examination of a greater range of parameters may be found by clicking on PLANETARY HABITABILITY.

Searching the web will reveal a number of sites devoted to the possibility of planets that could support higher forms of life. One such is Humans May Be the Only Intelligent Life in the Universe, If Evolution Has Anything to Say. Curiously, the author, Nick Longrich - Senior Lecturer, Paleontology and Evolutionary Biology, University of Bath, using an entirely different set of assumptions arrives at the same number: 1 in a billion.

I believe it is likely there are other planets with higher formers of life, but not many. The SETTI (search for extraterrestrial intelligence) program has been operating for about 40 years with no successful detections. My own assessment is that the overall requirements make the earth still more special with the probability of earth-like planets exceedingly rare.

Whatever the number, it is the earth that incubated life and helped it evolve over billions of years. And we are doing our best to kill it, windmills and solar cells notwithstanding.

MIT has a plan and it has the right ingredients except for two. How to implement it and how aggressive it should be. By agressive I mean how fast to we get carbon emissions down and do we do the job right and go backwards: scrub the air and get us from what will likely be 500 to 600 ppm carbon dioxide (it is now 420 and started at 270) and get it back to Bill McKibbens target of 350 (350.org). Any more than that and the earth will keep getting warmer and warmer and soon or later becomes a place of horrors.

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