AT FIRST GLANCE REPORTS OF A NEW "ALIEN EARTH STUDY" SUGGESTS OUR ESTIMATE OF THE CHANCES OF INTELLIGENT LIFE IN THE UNIVERSE WAS A GROSS UNDER ESTIMATE. WE DISAGREE.
SPACE AS AN OCEAN
LESSONS FROM THE AGE OF EUROPEAN MARINE EXPLORATION FOR THE SPACE AGE.
From the Book "PROTOCOLS" (c) 2012 by American Admiralty Books
Editor's Note: We first published this essay as part of a serial E-book about a year ago. The entire book may be read in the "MARITIME LITERATURE SECTION" just scroll down past the book reviews. Recently the Huff Post Science Section published an article titled " 'ALIEN EARTH' STUDY SUGGESTS MILKY WAY GALAXY HOLDS 45 BILLION EARTH LIKE PLANETS". When we published the essay below our definition of "Earth Like" was quite different from the author of the above referenced article, Mike Wall who apparently first posted it on Space.com
The planets the study refers to as "Earth Like" are simply somewhat near earth sized, with orbits around their sun that are roughly similar to Earth's. The study doesn't reveal anything about these planets rotation about their own axis or changing pole orientation which cause the day night and seasonal aspects of our own climate, nor do these studies indicate that any of these planets even have atmospheres. Most of these "new planets" are "estimated" planets meaning that they haven't actually been sighted but are estimated to exist based on a sampling of similar stars studied that had such planets. These "new"earth like" planets are products of statistical analysis and subject to all of the errors inherent in statistical projection using small samples.
These "new" planets are not revolving around yellow suns like our own but around "Red Dwarf" stars with surface temperatures roughly in the 2,000 degree Fahrenheit range cooler than our sun. Obviously, there will be some differences in types of radiation coming off a red dwarf as well as the radiant heat difference. There is no mention of the presence of moons or large outer "guard planets" as exist in our solar system to reduce the frequency of impacts with meteors and comets, there can't be, these "new planets" are not observed but products of statistical analysis. Finally as we observed in our original analysis we exist on an outer radial arm of our spiral shaped galaxy, a uniquely comparatively tranquil place in the galaxy in terms of meteors, comets, asteroids, and other naturally occurring space objects that can and do impact planets. By contrast the inner parts of the galaxy are a much more violent place.
Even if evolution had more time there as the report suggests, it is the time between massively destructive events that count. One of these objects whacked the dinosaurs which gave mammals a shot at reaching the apex of the biomass, but we had enough time between celestial body bombardments to evolve. For that to happen in the center of the galaxy the "earth like planet", and by that we mean a lot more than just roughly size and orbit distance from its star; would have be positioned in a unique solar system with an extraordinary collection of "outer guard planets". When we published our estimate of the chances of another space traveling civilization in our galaxy we based it on a much closer definition of "Earth Like". We don't think this latest study and statistical projection change our estimate of the chances of industrial and space-faring civilizations at all. Though subject to all of the potential error inherent in small sample statistical analysis, the study does suggest that the probability of at least microscopic life is higher than previous estimates and possibly not confined to planets circling yellow suns at the thought to be, appropriate distance.
A link to this report on the latest estimate of "Earth Like" planets in our galaxy is posted below, just remember "Earth Like" has different meanings in different contexts. In this latest study it refers only to relative mass, composition, and distance from the star orbited. Below the link is a reprint of our original posting, and below the reprint of our original posting are extracts from this latest study with comments from the author of our posting.
http://www.huffingtonpost.com/2013/02/06/alien-earth-milky-way-galaxy-earth-like-planets_n_2631063.html
YODA WHERE ARE YOU
What is the real likelihood that we'll meet intelligent life out there?
When European man first set out on the great voyages of exploration he expected to reach civilizations. He found both civilized and primitive tribal societies in abundance. Indeed the whole Earth while separated by what seemed like uncrossable seas, was in fact thickly peopled with diverse societies. Yet sea faring European man also found that much of the Earth was only thinly populated, in some cases so thinly as to be considered uninhabited. What are we likely to find in space?
Lets look at some probabilities in light of what some serious students of probability have said, based on the latest available information. For the purpose of simplicity, and keeping the discussion focused on the more immediate future, (the next couple of hundred years vice the next two thousand ) let's limit the discussion to our own galaxy. We shouldn't get beyond this area in the more or less immediate future. If there is going to be a first contact in the next two hundred years it will probably be with folks from our own galaxy.
In our galaxy which we call the "Milky Way". astrophysicist now estimate that we have about 135 billion stars. Presently most theories of stellar formation suggest that planetary systems around stars are common, perhaps the norm. We have certainly been discovering a lot of these planets of late now that we have a better idea of how to detect them from Earth or orbital observatories. Some of these planets have been found in constellations that sailors have navigated by for centuries. So lets follow the line of reasoning of Carl Sagan and some of the numbers provided by Isaac Asimov and Stephen H. Doyle and call the number of planetary systems something just a little shy of 135 billion. Lets assume that each of these planetary systems contains 6 to 12 planets. That gives us "billions and billions" (Carl Sagan) in fact , about a trillion "worlds" in the Milky Way. Now of these somewhat less than a trillion "worlds" some are circling stars much larger, smaller, colder, or hotter than ours. Some are circling twin stars and receiving radiations of sorts that we can only begin to imagine. Some have rotations that are too slow to regulate temperature decently for life, some are too near their stars, some too far. In short the vast majority aren't very Earth like. But near a trillion "worlds" is a lot of "worlds".So the law of probability makes it highly likely that some are indeed Earth like.
Stephen H. Dole and Issac Asmimov applied probability reasoning to the question in PLANETS FOR MAN (Random House 1964). and arrived at an estimate of as many as 640 million Earth like planets , at least in terms of having approximate mass, temperatures, orbit/rotation, chemistry and a sun like star to rotate about at approximate earth like orbital distance. This boils down to only one star out of every 210 has anything even similar to an Earth like planet. Only one planet out of every 4,000 is estimated to be Earth like. Now assuming 640 million Earth like, life generating planets in our galaxy, what does probability theory say about intelligent space faring life being out there? Asimov looked beyond Sagan's cataloging of "billions and billions" of "worlds" to try to estimate the actual probability of some space faring civilizations in our galaxy. Some of his reasoning can be found in
THE PLANET THAT WASN'T.(Double day and Company 1976). Let's follow some of Sagan's, Asimov's and Dole's math here.
As Asimov observed , on Earth life took about three billion years to evolve to its present state . Civilization has existed for about 10,000 years. So the ratio of uncivilized years to civilized is 300,000 to 1. So if we consider Earth to be about average, and consider that life started in different times in different places it should be safe to estimate that civilization exists on 1 out of every 300,000 of these Earth like Worlds at best. According to Carl Sagan' like line of reasoning that would give us an estimated 2, 150 civilizations in our galaxy ranging in technological development from pre-Roman like to far beyond modern day America. (Notice I wrote according to the Sagan line, Asimov injects some new considerations later on.) Now looking at industrial civilization we see Earth has had one for about 200 plus years out of 2,000 years of well documented civilized life. So of our galaxy's estimated 2,150 civilizations, a likely ratio of non or pre-industrial societies to industrial societies would be 50 to 1. That leaves us with an estimated 43 probable industrial worlds out there. Not all of them will be space faring yet. So lets estimate the space farers at 21 societies, figuring ourselves to be the median.
OK, so is it probable that 21 societies in our galaxy are capable of some type of space travel? It's possible, but hardly probable based on our current knowledge. Asimov's biggest dampener on Sagan's estimate is the fact most of these planets on which we based all of the above calculations on are located in the circular portion of our spiral shaped galaxy while we are located on an outer spiral arm. The circular portion is very violent in terms of meteors, astroloids, comets and similar things hitting the planets there. The closer to the middle of the galaxy the more violent the neighborhood. Evolution needs extensive time between cosmic bombardments to evolve intelligent life. So if we ignored this basic fact in calculating a probable 21 space-faring societies in our galaxy, our estimate is wildly optimistic. Considering the facts as we think we know them today, the fact that we are here is astounding. But then the galaxy is a really big place and we truly don't know all of the facts
Lets look at some probabilities in light of what some serious students of probability have said, based on the latest available information. For the purpose of simplicity, and keeping the discussion focused on the more immediate future, (the next couple of hundred years vice the next two thousand ) let's limit the discussion to our own galaxy. We shouldn't get beyond this area in the more or less immediate future. If there is going to be a first contact in the next two hundred years it will probably be with folks from our own galaxy.
In our galaxy which we call the "Milky Way". astrophysicist now estimate that we have about 135 billion stars. Presently most theories of stellar formation suggest that planetary systems around stars are common, perhaps the norm. We have certainly been discovering a lot of these planets of late now that we have a better idea of how to detect them from Earth or orbital observatories. Some of these planets have been found in constellations that sailors have navigated by for centuries. So lets follow the line of reasoning of Carl Sagan and some of the numbers provided by Isaac Asimov and Stephen H. Doyle and call the number of planetary systems something just a little shy of 135 billion. Lets assume that each of these planetary systems contains 6 to 12 planets. That gives us "billions and billions" (Carl Sagan) in fact , about a trillion "worlds" in the Milky Way. Now of these somewhat less than a trillion "worlds" some are circling stars much larger, smaller, colder, or hotter than ours. Some are circling twin stars and receiving radiations of sorts that we can only begin to imagine. Some have rotations that are too slow to regulate temperature decently for life, some are too near their stars, some too far. In short the vast majority aren't very Earth like. But near a trillion "worlds" is a lot of "worlds".So the law of probability makes it highly likely that some are indeed Earth like.
Stephen H. Dole and Issac Asmimov applied probability reasoning to the question in PLANETS FOR MAN (Random House 1964). and arrived at an estimate of as many as 640 million Earth like planets , at least in terms of having approximate mass, temperatures, orbit/rotation, chemistry and a sun like star to rotate about at approximate earth like orbital distance. This boils down to only one star out of every 210 has anything even similar to an Earth like planet. Only one planet out of every 4,000 is estimated to be Earth like. Now assuming 640 million Earth like, life generating planets in our galaxy, what does probability theory say about intelligent space faring life being out there? Asimov looked beyond Sagan's cataloging of "billions and billions" of "worlds" to try to estimate the actual probability of some space faring civilizations in our galaxy. Some of his reasoning can be found in
THE PLANET THAT WASN'T.(Double day and Company 1976). Let's follow some of Sagan's, Asimov's and Dole's math here.
As Asimov observed , on Earth life took about three billion years to evolve to its present state . Civilization has existed for about 10,000 years. So the ratio of uncivilized years to civilized is 300,000 to 1. So if we consider Earth to be about average, and consider that life started in different times in different places it should be safe to estimate that civilization exists on 1 out of every 300,000 of these Earth like Worlds at best. According to Carl Sagan' like line of reasoning that would give us an estimated 2, 150 civilizations in our galaxy ranging in technological development from pre-Roman like to far beyond modern day America. (Notice I wrote according to the Sagan line, Asimov injects some new considerations later on.) Now looking at industrial civilization we see Earth has had one for about 200 plus years out of 2,000 years of well documented civilized life. So of our galaxy's estimated 2,150 civilizations, a likely ratio of non or pre-industrial societies to industrial societies would be 50 to 1. That leaves us with an estimated 43 probable industrial worlds out there. Not all of them will be space faring yet. So lets estimate the space farers at 21 societies, figuring ourselves to be the median.
OK, so is it probable that 21 societies in our galaxy are capable of some type of space travel? It's possible, but hardly probable based on our current knowledge. Asimov's biggest dampener on Sagan's estimate is the fact most of these planets on which we based all of the above calculations on are located in the circular portion of our spiral shaped galaxy while we are located on an outer spiral arm. The circular portion is very violent in terms of meteors, astroloids, comets and similar things hitting the planets there. The closer to the middle of the galaxy the more violent the neighborhood. Evolution needs extensive time between cosmic bombardments to evolve intelligent life. So if we ignored this basic fact in calculating a probable 21 space-faring societies in our galaxy, our estimate is wildly optimistic. Considering the facts as we think we know them today, the fact that we are here is astounding. But then the galaxy is a really big place and we truly don't know all of the facts
| The Milky way our home galaxy as it would appear if viewed from overhead |
NASA IMAGE WITH ARMS LABELED
Author's notes on recent new study:
FROM: Alien Earth Study Suggests Milky Way Holds 4.5 Billion Earth Like Planets by Mike Wall published in Space . Com 2/6/2012 and the Huff Post Science Section 2/7/2016
" Astronomers have calculated that 6 percent of the galaxy's 75 billion or so red dwarfs — stars smaller and dimmer than the Earth's own sun — probably host habitable, roughly Earth-size planets. That works out to at least 4.5 billion such American Admiralty Books Safety & Privacy Policies "alien Earths," the closest of which might be found a mere dozen light-years away, researchers said."
AAB Note: This is a study of Red Dwarfs which are significantly different from our own sun, to start with their surface is thousands of degrees cooler. "Earth sized" is a long way from being "Earth like". We think it takes a leap of logic to assume similar sized planets circiling very different types of stars in an optimum orbital zone are "alien earths".
"In the new study, Dressing and her colleagues re-analyzed the American Admiralty Books Safety & Privacy Policies red dwarfs in Kepler's field of view and found that nearly all are smaller and cooler than previously thought.
This new information bears strongly on the search for Earth-like alien planets, since roughly 75 percent of the galaxy's 100 billion or so stars are red dwarfs."
AAB Note: Red Dwarfs are about 2,000 to 5,000 degrees F cooler on their surface than our yellow sun, this would indicate that planets orbiting such a star in the zone that Venus, earth, and Mars circle our sun would on average be cooler, the inhabitable zone might be closer in than we presently think. We don't know what types of solar radiation planets orbiting Red Dwarfs receive compared to the out put of our own yellow sun.
" The researchers determined that 95 Kepler exoplanet candidates orbit red dwarfs. Using this information and their newly calculated stellar (and planetary) profiles, the team calculated that about 60 percent of red dwarfs likely host worlds smaller than Neptune.
Dressing and her colleagues then determined that Kepler has spotted three roughly Earth-size exoplanet candidates in the habitable zones of their parent red dwarfs.
One of these worlds is Kepler Object of Interest (KOI) 1422.02. This candidate's newly calculated size is 90 percent that of Earth, and it circles its star every 20 days. If the planet (and these characteristics) are confirmed, KOI 1422.02 may be the first "alien Earth" ever discovered."
AAB Note: We have no doubt that (KOI) 1422.02 is roughly earth sized, or orbits its star every 20 days in the speculative "best zone", but confirming those two facts don't prove an earth twin. How long is its day night cycle, does it have an atmosphere, what is the composition of the atmosphere, what is the average surface temperature? Is in a outer spiral of the galaxy or nearer the base of a spiral or the outer rim of the circular section?, Are there outer "guard planets", how violent in terms of cosmic collision objects is its neighborhood. Remember Earth shares the "life zone" with Venus and Mars but is nothing like those planets. Finding a pair or a few characteristics of a planet held in common with Earth is grounds to focus attention on studying that planet. It is a far cry from the actual discovery of an "alien earth".
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