Life on other planets

how many suns do you think are in this universe? what about milkways? do you really think there could be a posibility that there is not other life forms out there? hell we are them!
 
kristen83 said:
how many suns do you think are in this universe? what about milkways? do you really think there could be a posibility that there is not other life forms out there? hell we are them!
What?
 
I believe life exists on other planets, but I don't believe that life has visited us or even knows we exist. Even from a relatively close distance across space, Earth is far too small a planet to be seen and much too close to its sun to be observed closely. If our solar system was being observed from some other point in the galaxy, Jupiter and Saturn would be discovered long before Earth, if it ever was. So, unless some alien intelligence had picked up some of our radio transmissions, they wouldn't even know to look our way, much less waste amazing levels of resources to send wave after wave of spacecraft here to perform enemas on cows and doodle on wheatfields. Now, it is possible that an alien intelligence has picked up our radio transmissions, but as these transmissions have so far only penetrated about 100 light years into space, that intelligence would have to be 100 light years to us or closer, and would only now be picking up transmissions that were made 100 years ago. And even if they started sending back a message tomorrow, if they're 100 light years away, we won't get it for a century.

Of course, there could be intelligences that are much closer than 100 light years away, but radio telescope technology has been scanning the skies for 50 years now and not received a single message from anywhere. So either there's no intelligent life at >=50 light years distance, or there is but it hasn't yet developed radio technology, or they're deliberately not sending anything out into space, which would be impossible. This would mean to me that any life with intelligence <= ours exists beyond the 50 light years distance, and that's pretty far away.
 
They actually have an equation that estimates the amount of intellegent life in the universe.

http://www.activemind.com/Mysterious/Topics/SETI/drake_equation.html said:
Description
The Drake Equation was developed by Frank Drake in 1961 as a way to focus on the factors which determine how many intelligent, communicating civilizations there are in our galaxy. The Drake Equation is:

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.


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The real value of the Drake Equation is not in the answer itself, but the questions that are prompted when attempting to come up with an answer. Obviously there is a tremendous amount of guess work involved when filling in the variables. As we learn more from astronomy, biology, and other sciences, we'll be able to better estimate the answers to the above questions.
 
i think some of those questions need to be more detailed, such as "what conditions are necessary to support life, and on how many worlds are those conditions present?"

i find the "answer" to "% of those who want to communicate" interesting... 10-20% only? pretty lonesome aliens.
 
To put another angle on it there is also the Fermi Paradox, which I suppose goes something along the lines of: If there is intelligent life out there where are they? I guess a craft going even a fraction of the speed of light over the course of the existence of the galaxy could travel end to end. Robot colonizers could land on a planet, use it resources to build more colonizers and continually expand outward etc...
http://en.wikipedia.org/wiki/Fermi_paradox

Plus sometimes I personally think about how neccesary developing intelligence is. A brain like ours is great for helping our survival, but its certainly not required. Sometimes it seems to me we got lucky that our ancestors faced enviromental & selection pressures that stimulated our minds.

Anyway I believe there has to be life out there. But intelligent life? In addition intelligent life that devolps harnesses radiowaves and spacetravel. Though it seems the Drake Equation is more than broad enough currently to accept all sorts of opinions.