Does life exist on other planets beyond our Solar system?

The whole question of life elsewhere comes down to two questions:

1. How difficult is it for life to come into existence out of non-life.

2. How unique is the Earth's environment and its environmental history.

The first question addresses whether, given the right environment, would it be likely that life would start up anywhere? We suspect that the answer to that question is: Very Likely. The reason is that the more we look around the universe the more precursors to life we find. The more we look around the Earth the more we find evidence that life on earth happened soon after the Earth was created (geologically speaking). The question of life elsewhere in our solar system is probably the most important question that all of our space exploration is aimed at answering. We have not found any slam-dunk evidence for life elsewhere but we continue to look.

The second question addresses the nurturing of primitive life into complex organisms. On Earth (our only example of life) it took over 3.5 billion years to come up with man. Three billion years where the environment on the Earth was relatively stable. For about 3 billion of those years life was single celled. During the last 3.5 billion years the environment on Earth was favorable to the continued development of life even in the face of a changing solar environment. Is it likely that such a planet would exist elsewhere in the universe? The numbers of stars are staggering so it might seem a virtual certainty - but the Earth has developed life and as far as we know Mars and Venus have not. They seem like very similar planets to the Earth. It is more complicated than just “Earth like planets.”

For instance, our sun, Sol, has over the last 3 billion years increased its output by about 25% due to normal stellar evolution. That is an enormous change in output and without some compensating factor the Earth would have gone from an ice ball to a barren Venus like planet over that time. It didn't- but we don't know what the factor or factors were that maintained such a constant environment.

Now consider the likelihood of the Earth receiving visits from aliens. The chances of alien life forms visiting us come down to two additional questions. One addresses the spatial problem and one the temporal problem.

1. If a technologically sophisticated life form did develop elsewhere in the universe would it be likely that they would be contemporaneous with man when he is also technologically sophisticated.

2. Is it likely that a technologically sophisticated life form could develop near enough to us so that they could reasonably visit the Earth.

When alien extraterrestrial life is considered what is usually referred to is: technologically sophisticated life. We aren’t usually talking about bacteria or worms or even Homo Erectus visiting the Earth. Humans have been technologically sophisticated for only about 100 years. Our first satellite to orbit another body was only 42 years ago. That is 100 years out of a total history for the Solar System of 4,500,000,000 years and of 13,500,000,000 years for the universe. The chances of a second life form becoming technologically sophisticated and also overlapping with man- also being technologically sophisticated are vanishing small. Alien civilizations may have come into being, developed and become extinct hundreds of millions of years before or after man.

The problem of travel is also daunting. With all of our present sophistication we do not have the ability to travel to even the nearest star. The development of super-sophisticated intelligent extraterrestrial life capable of traveling to nearby stars would first require a nurturing environment existing for billions of years and then the development of technology far beyond ours. That in itself is very, very, very unlikely. For it to happen a second time near enough to our star, Sol, so travel would be possible is vanishingly unlikely. In talking about alien visitors to Earth there is an implied uncovering of a ‘new physics’ that would allow what our present physics does not allow- travel over large distances in reasonable time frames. It may be that that physics does not exist.

Man presently might have the technology and ability to send a man to Neptune. At the speed of 50,000 miles per hour we would need to provide life support to the astronauts for several YEARS. It would take 6.4 years at 50,000 mph to go to Neptune – ONE WAY. Now consider the NEAREST star. At a speed of 1,000,000 miles per hour it would take 2,885 years just to get there AND that is only to the nearest star!

Unless there is a new physics unknown to man there is essentially no way for aliens to visit the Earth. Also, there are too few nearby stars for there to be a high probability for the development of technologically sophisticated life forms.

Consider this; if the sun were about the size of a golf ball, 1 inch in diameter, the orbit of Neptune wou

I completely agree with you, I think it is absolutely possible there is life on other planets!!! Human life, and life in general may not be that unusual at all. How many planets, stars and galaxies have we actually been to? There is no way to disprove of life in places that we have never been. We thought the earth was flat a couple hundred years ago, so what people think is not always a good indication of what's true. I think the possibilities are endless. Life on other planets may be more evolved than humans, and perhaps they do not want us to discover them at this time. Some forms of life may be similar to humans, and others may be totally incomprehensible to us. One reason that people like to say that life can't exist on other planets is because the Bible says that God created the earth, but it did not mention life in other places. So some people believe that life as we know it can only exist on earth.

We do not yet know nearly enough to answer your question. It seems likely that life can exist on many of the huge number of planets that probably exist in the vast universe...BUT "seems likely" and "probably" are not the same as "certainly". It is not certain that there are other "universes". Life might be based upon different elements than the carbon that earth life uses. Your question is filled with speculation, and Gautama the Buddha told men 2650 years ago that they should not waste much time upon idle speculation.

i'll keep it short, yeah there is probably life in our very own solar system, and no better place to look than mars (for real it's there).

Scientist believe that plant RNA was produced at the time of the big bang when everything began to cool. if this is true then the universe could be littered with life, where it can take hold.

Study Fermi's Paradox

(wikipedia/google it)

Tricky question since the best definition of 'life' is: "A temporally and spatially localized suppression of the laws of thermodynamics and capable of reproducing the environment in which it occurs."

Doug

No one knows yet, but i truly belive there does. Even if i am wrong I think it would be a very ignorant person who refuses to believe that it may even be possible.

Maybe. Ice was found on Mars which may support life

With the size of the universe I believe life outside our solar system is inevitable.

Tantamount I like that word.

Logically is not to exist doesn't it. I agree with your version.