Milky Way Could Contain 100 Million Planets with Complex Life

[MountainsWinAgain]

-In 1961, Frank Drake set out his formula for estimating the number of intelligent civilizations in our galaxy. A new study from the University of Texas at El Paso looks to improve on Drake’s estimate by studying data from more than 1,000 exoplanets for a number of factors, and the number they came up with is enormous

-The new study was authored by Louis Irwin and ranks the exoplanets with a “biological complexity index,” a number the researchers assigned by looking at parameters like the exoplanets’ distance from their star, temperature, density, age, and chemistry. All the factors of the “biological complexity index” are ones thought key to a planet supporting life.

-Only 1% to 2% of the exoplanets looked at in the study scored a high enough “biological complexity index” to be good candidates for complex life. That seems like a low result, but when applied to the vastness of space it’s still huge.

-If there are estimated 10 billion stars in the Milky Way, and each star has at least one planet, then that means 100 million planets could score a “biological complexity index” score high enough to make them likely to support life.

100 million planets!!

[Jackalope]

10 billion stars in the milky way? There's at least 100 billion.

On the other hand, I'd bet that less than 1% of planets can support complex life. Perhaps far less.

[Anomalocaris]

10 billion stars in the milky way? There's at least 100 billion.

On the other hand, I'd bet that less than 1% of planets can support complex life. Perhaps far less.

Since our empirical experience with complex life is limited to exactly one biochemical lineage, and our fundamental understanding of complex biochemistry is still far too sketchy to be able to predicting a priori, as oppose to merely describe ex post, most biochemical processes that made our one biochemical lineage, I would hesitate to say just how many places (not necessarily just planets) can support complex life.

I saw one theoretical model which suggests high temperature (millions of degrees) fast paced (metabolic reactions a million times faster than life on earth) iron based biochemistry and complex life ought to be theoretically possible on the extremely high gravity, high pressure environment on the surface of neutron stars.

[Jackalope]

Yeah - point taken. It's fairly speculative at this point - until we know more, I'm sticking with wagering that complex life requiring a fairly narrow band of conditions. Despite that, it seems that life ought to have arisen a great many times. 100 million planets with complex life seems optimistic.

Yep, I realize that this is an argument from ignorance - or would be, were I making an argument. :p