What are the odds for a planet in the universe to have the necessary means for sustaining intelligent life?

Question

How likely is it that the Earth is the only one? I've heard people say that the universe is so vast that there must be other life somewhere, but I'm wondering if there are any Astonomy people out there who have some actual calculations supporting or negating this idea.

Answer 1

Hello earthlings, There is other life out there but your government refuses to accept it. Many of my brothers and sisters have been placed in something you call area 51.

I'm currently in orbit around earth in my ship waiting for the high counsel to decide if we should destroy earth for it's many crimes.

Answer 2

So far, at least 1:8.

Any calculations I have seen for the entire Universe (e.g. Drake) are based on so many assumptions that the resulting calculation is not much more than a guess.

However, given that there about 10^21 stars in the Universe, any conclusion other than that there must be life elsewhere would be the height of human conceit.

Answer 3

The Drake equation is highly flawed, but it is fun to work with if only to get us thinking about the things that go into creating and sustaining life. Check this out:

"The Drake equation (also known as the Green Bank equation or the Sagan equation) is a famous result in the speculative fields of xenobiology, astrosociobiology and the search for extraterrestrial intelligence.

This equation was devised by Dr Frank Drake (now Emeritus Professor of Astronomy and Astrophysics at the University of California, Santa Cruz) in the 1960s in an attempt to estimate the number of extraterrestrial civilizations in our galaxy with which we might come in contact. The main purpose of the equation is to allow scientists to quantify the uncertainty of the factors which determine the number of extraterrestrial civilizations. In recent years, the Rare Earth hypothesis, which posits that conditions for intelligent life are quite rare in the universe, has been seen as a possible refutation of the equation." [See source.]

The Drake equation is about life as we know it on Earth. Up until a few years ago, the pundants thought all life had to be solar based. That is, everything had to have access to the sun or to other things (like food) that had that access.

But that is no longer the thought. They have discovered life near the volcanic vent holes in the Atlantic rift where giant worms live without benefit of any solar access whatsoever. They in fact, live off the sulfur products produced by the vents.

The Drake equation is flawed, too, it that it posits our Earth is a representative planet of other commonplace similar planets. The Rare Earth hypothesis disputes that assumption. Check this out:

"The Rare Earth hypothesis is the contrary of the principle of mediocrity (also called the Copernican principle), whose best known recent advocates include Carl Sagan and Frank Drake. The principle of mediocrity maintains that the Earth is a typical rocky planet in a typical planetary system, located in an unexceptional region of a large but conventional barred-spiral galaxy. Ward and Brownlee argue to the contrary: planets, planetary systems, and galactic regions that are as friendly to complex life as are the Earth, the solar system, and our region of the Milky Way are probably extremely rare. If so, the Earth could be the only place in the Milky Way, and perhaps even in the entire universe, featuring complex life." [See source.]

So, as you can see, a lot of learned people have given life on other planets a lot of thought. I, frankly, lean towards the Rare Earth folks because I believe life on our planet resulted from a very rare combination of events that is highly unlikely to occur more than once.

Answer 4

The odds a very great,and it ,no doubt has happened at least billions of times in all areas of the universe.
There is a formula for calculating the chances but it is still pure speculation.
We appear the be the product of a universe that,some way developed the capacity to become aware of itself.
It would not stop with only us.

Answer 5

Carl Sagan and others estimate thousands in this galaxy, but if you read Astrobiology and take into account how unlikely our Earth/ moon situation is likely to be duplicated in a solar system with a Jupiter and a metalliferous G type sun, 20,000 - 40,000 light years from the nucleus of a spiral galaxy, it would probably be in single figures for this galaxy of 400,000,000,000 suns, which is not to say that intelligent aliens motivated to develop and use technology are there, or have been, or will be. Life probably abounds, but multicellular life will be much rarer.

Answer 6

Look up "Drake Equation" on your favorite search engine. It calculates just the number you are looking for (actually the potential number of civilizations we can communicate with in our Galaxy). Unfortunately, no one knows the exact values of the variables in the equation. But it's fun to guess the values and get an upper and lower limit on what the number might be!

Answer 7

The Universe is such a huge place, there has to be life out there. It is very unlike that Earth is the only planet out there with life.

Answer 8

Well, if the Universe is Billions of years old at least, and this is the only one so far......
I would say less than 1 in a billion. It is probably much lower than that.

Answer 9

Enter the famous Drake equation which addresses just what you ask -

http://en.wikipedia.org/wiki/Drake_equation

Answer 10

My best guess would be, if there is other life out there then it must be here with in us in higher dimension.