How many planets have advanced civilizations?

Answer 1

This question is no longer a matter of idle speculation. Soon, humanity may face an existential shock as the current list of a dozen Jupiter-sized extra-solar planets swells to hundreds of earth-sized planets, almost identical twins of our celestial homeland. This may usher in a new era in our relationship with the universe: we will never see the night sky in the same way ever again, realizing that scientists may eventually compile an encyclopedia identifying the precise co-ordinates of perhaps hundreds of earth-like planets.

Today, every few weeks brings news of a new Jupiter-sized extra-solar planet being discovered, the latest being about 15 light years away orbiting around the star Gliese 876. The most spectacular of these findings was photographed by the Hubble Space Telescope, which captured breathtaking photos of a planet 450 light years away being sling-shot into space by a double-star system.

But the best is yet to come. Early in the next decade, scientists will launch a new kind of telescope, the interferometry space telescope, which uses the interference of light beams to enhance the resolving power of telescopes.

Answer 2

It depends on what you mean by an "advanced civilization." The human race is the only civilization we know about, and it's pretty retarded, in the opinion of anybody that has taken a good look around.

But we can't accuse the residents of other celestial bodies of being as uncivilized as "civilized human beings" are.

But I'm sorry to have to say that the answer to your question remains indeterminate. There is no way to find out how many planets exist or how many of them are occupied by living things, or how many of those are what we would acknowledge as "sentient beings," or how many of those use stone axes, or how many of them have iPods, MaxiPads, Enemy Combatants, or other signs of what some people consider an "advanced" civilization.

If the universe is truly infinite in extent, then there may be an infinite number of civilizations at an infinite number of various degrees of advancement.

If the universe is finite in extent, there will be finite number of each of these things.

Answer 3

N = N* fp ne fl fi fc fL
The equation can really be looked at as a number of questions:

N* represents the number of stars in the Milky Way Galaxy
Question: How many stars are in the Milky Way Galaxy?
Answer: Current estimates are 100 billion.
fp is the fraction of stars that have planets around them
Question: What percentage of stars have planetary systems?
Answer: Current estimates range from 20% to 50%.
ne is the number of planets per star that are capable of sustaining life
Question: For each star that does have a planetary system, how many planets are capable of sustaining life?
Answer: Current estimates range from 1 to 5.
fl is the fraction of planets in ne where life evolves
Question: On what percentage of the planets that are capable of sustaining life does life actually evolve?
Answer: Current estimates range from 100% (where life can evolve it will) down to close to 0%.
fi is the fraction of fl where intelligent life evolves
Question: On the planets where life does evolve, what percentage evolves intelligent life?
Answer: Estimates range from 100% (intelligence is such a survival advantage that it will certainly evolve) down to near 0%.
fc is the fraction of fi that communicate
Question: What percentage of intelligent races have the means and the desire to communicate?
Answer: 10% to 20%
fL is fraction of the planet's life during which the communicating civilizations live
Question: For each civilization that does communicate, for what fraction of the planet's life does the civilization survive?
Answer: This is the toughest of the questions. If we take Earth as an example, the expected lifetime of our Sun and the Earth is roughly 10 billion years. So far we've been communicating with radio waves for less than 100 years. How long will our civilization survive? Will we destroy ourselves in a few years like some predict or will we overcome our problems and survive for millennia? If we were destroyed tomorrow the answer to this question would be 1/100,000,000th. If we survive for 10,000 years the answer will be 1/1,000,000th.
When all of these variables are multiplied together when come up with:
N, the number of communicating civilizations in the galaxy.

Answer 4

8

Answer 5

To answer this question a scientific discovery has to be determined. So far the Earth is the only planet which contains human civilization . Enjoy it and appreciate as much as you can.

Answer 6

I can't think of one. The advance civilization on the Earth is questionable.

Answer 7

Less than one for every 250,000 stars.

With as many as 250 billion stars in our galaxy, that means there should be a million or so in the Milky Way alone.

They just haven't sent us their addresses yet.

Maybe they think we are still monkeys, and wouldn't understand even a simple message yet.

Or maybe they're waiting for us to bring ourselves to the brink of extinction before coming around to see us.

I know people with relatives like that.

Answer 8

None that we know of. Maktar 7 in the Quampa Galaxy may hold a civilization somewhat advanced.

Answer 9

Greater than or equal to 1.

Answer 10

Two