5,000 planets discovered to date, with 3200 of those bodies verified as planets. Seems like a lot, but consider that today NASA announced 1284 of those discoveries. Okay that’s a start in a very small sector of our galaxy. But then we have to begin culling those numbers.
Of 1284 planets announced today, 550 are of the rocky variety. Not to say some sort of lifeform could not exist on Neptune or Jupiter, but if it does it will be so different than what we perceive as life that we may not even know that it is a lifeform. So when looking for planets to support lifeforms or a new galactic manifest destiny we’re pretty much limited to the rocky variety of planets.
Next, again considering our own type of lifeforms we need the planet to be in what is referred to as the goldilocks zone, where it is neither too hot nor too cold. That really does a number on the prospects. As of yesterday there were only 12 planets identified to be in the habitable zone, today the number has nearly doubled to 21.
Will we find extra-terrestrial life? Almost certainly. However, the question of extra-terrestrial civilizations will be more of a challenge. I believe it is likely that we will find some sort of microbial lifeforms within our own solar system. We may even find archeological evidence of an ancient civilization on Mars. Who knows, maybe we all started out as Martians eons ago when Mars had an atmosphere that could sustain life forms as we know them.
Next generation astronomical technology is coming soon. One of the missions of the next generation telescopes is scout not just for planets but for signs of life as well. Something to look forward to :o)