Extra Terrestrials have been a major part of science fiction pop culture for the last century.

A report by astrophysicist David Piegel from Princeton University and physicist Edwin Turner from the University of Tokyo indicates that they might just remain that way: fiction.

According to a new paper published on arXiv.org,, the scientific equation known as the 'Drake Equation' which scientists (SETI) are using to predict the likelihood of discovering extra terrestrials, is flawed.  It is not that the equation is directly flawed, but the way the scientists are using it.

Scientists using the Drake Equation by estimating the total number of radio transmitting intelligent beings in the galaxy by multiplying a number of variable fractions, including the number of stars in the galaxy, the fraction that have planets, the fraction that could be habitable, etc. -all of which are just a speculation since scientists don't know any of the true numbers. They try to make their best educated guess on how many stars and planets exist in the Milky Way based on a trend in current data.   

The current prediction that scientists in the SETI community are coming to based on the Drake Equation is that intelligent life will be discovered within 20 years.  The estimate that they are using is that there are 10,000 intelligent civilizations in the Milky Way Galaxy. 

However, the authors of the new paper are saying the prediction is severely flawed because of one of the numbers scientists are speculating on.  The number in question is that scientists are assuming that 100 percent of the planets that could possibly support life are supporting life.   

Piegel and Turner make the argument that life could in fact be a rather rare occurrence in our galaxy.  This estimate would greatly reduce our chances of ET phoning Earth in the next 20 years.

They say that scientists are biased based on our current understanding of Earth.  Life appeared on Earth only a few hundred million years after it formed, giving intelligent life at least 3.5 billion years to develop.  The report doesn't dismiss chances of intelligent life existing. It just states that there is no way that life could have formed as quickly as it did on earth 100 percent of the time.  This would mean that intelligent life has yet to form on some habitable planets, or life in itself has yet to form. 

"Although life began on this planet fairly soon after the Earth became habitable, this fact is consistent with...life being arbitrarily rare in the Universe," the report says.

They go on to back up their claims with their own mathematical formulas.

The report says that if in the future, scientists are able to discover that life had formed early on Mars, they would have a better measurement to make such a claim as SETI is making.  It would give them two completely different proven model scenarios to make a measurement of how life forms on a habitable planet.  However, since only one point is currently being used, the estimate stands as an unstable theory. 

Source article:
http://arxiv.org/PS_cache/arxiv/pdf/1107/1107.3835v1.pdf

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