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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."
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.
Letter To Iran
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. "
"The greatest lesson in life is to know that even fools are right sometimes" - Winston Churchill
Alien life in the universe that we could encounter, depending on the climactic conditions, gravity and atmosphere would be very different from humans to say the least. They would not be all humanoid races that speak english and can walk and act just like humans, they might be boneless creatures like an octopus or evolved dolphins that pilot ships full of water, or [...].
Ships full of water - multiply the difficulties to escape the gravity well by about 1000.
Imagine developing metallurgy and special ceramics (I reckon these would be needed for at least propulsion) in/under water...
Questions raise, answers kill. Raise questions to stay alive.
In a couple years kepler will have sufficient data so we can estimate the number of rocky worlds in habitable zones, that's what is most interesting to me. Once we find such worlds, we'd need to fund the type of probe that can analyze atmosphere, life as we know it does a very detectable transformation. Then step up our optical SETI efforts in those world's directions (they won't use radio waves, sorry microwave SETI dudes....)
Or even some clever use of entangled particle pairs. (Simply because we haven't figured out how to use them for comm doesn't mean others haven't.)
Personally though, I think seti is looking for the wrong things.
Instead of trying to eavesdrop on the grey aliens ordering space pizza from planet foodcourtia, they should be looking for localized light displacements from known stellar markers, as caused by the huge gravitational eddies that several hypotherical FTL systems would make. Interstellar highways would show up on a sufficiently detailed map of the CBR because of the regular disruptions.
(This assumes something like an albucare (however you spell his name...) warp drive though, which create a wave of negative spacial curvature behind the vessel, and a synthetic gravity well in front.)
Our current CBR maps are pretty coarse, since we are dealing with single measurement devices with very wide frequency emmisions, so a highway search would require interferometry to be fruitful. We need to launch about 50 more COBE sats up.