Astronomers Estimate Milky Way May Have 100 Billion Alien Worlds

astroengine writes "Last year, using the exoplanets discovered by the Kepler space telescope as a guide, astronomers took a statistical stab at estimating the number of exoplanets that exist in our galaxy. They came up with at least 50 billion alien worlds. Today, astronomers from the Space Telescope Science Institute (STScI) in Baltimore, Md., and the PLANET (Probing Lensing Anomalies NETwork) collaboration have taken their own stab at the 'galactic exo-planetary estimate' and think there are at least 100 billion worlds knocking around the Milky Way."

Comments

100 billion likely way too low

[DumbSwede]

100 Billion is likely too low. Based on a survey of close suns using Doppler shift indicated at least 50% had planetary systems of some sort. I think the future will boost this percentage to 90% or better, probably virtually all suns have some kind of orbiting object that could be termed a planet. Depending on where you draw the line on size this makes for probably more than 2 Trillion alien worlds in the Milky Way alone (which is estimated to have 200-400 billion suns).

As for examining Kepler Objects of Interest (KOIs) more closely it seems there is little point to single them out. So what if we know they have planets -- everywhere you could point a radio dish there are planets. I am a big supporter of SETI and this is all good news for SETI, but it doesn't do anything to narrow the search.

Oblig. Arthur C Clarke quote

[Kittenman]

“Behind every man now alive stand thirty ghosts, for that is the ratio by which the dead outnumber the living. Since the dawn of time, roughly a hundred billion human beings have walked the planet Earth.

Now this is an interesting number, for by a curious coincidence there are approximately a hundred billion stars in our local universe, the Milky Way. So for every man who has ever lived, in this Universe there shines a star.

But every one of those stars is a sun, often far more brilliant and glorious than the small, nearby star we call the Sun. And many--perhaps most--of those alien suns have planets circling them. So almost certainly there is enough land in the sky to give every member of the human species, back to the first ape-man, his own private, world-sized heaven--or hell.

How many of those potential heavens and hells are now inhabited, and by what manner of creatures, we have no way of guessing; the very nearest is a million times farther away than Mars or Venus, those still remote goals of the next generation. But the barriers of distance are crumbling; one day we shall meet our equals, or our masters, among the stars. "