Math Quiz 2.....

[tecoyah]

Our next hypothetical:

Science has placed the observed universal Star Count at appx. 10 to the 21st, or 1,000,000,000,000,000,000,000 stars. Given that the only system humankind has studied contains at a minimum 3 planets minimally capable of sustaining some form of life, and the continuous discovery of planets around the majority of these stars.....What would be the chance that the Earth is unique in harboring lifeforms?

 

[paulmarkj]

Using the Drake equation at The Drake Formula--Estimating Life in the Universe

I reckon there are 500 other planets harbouring life, but this involves estimates, so it could be anything from 5 to 50,000,000!

Have you got any more information regarding the bit where you said "the only system humankind has studied contains at a minimum 3 planets minimally capable of sustaining some form of life" I hadn't heard that before. Humankind are studying stars that are more likely to have planets, and so the sucess rate might not be a good if a random sample were taken.

 

[Spartacus FPV]

Our next hypothetical:

Science has placed the observed universal Star Count at appx. 10 to the 21st, or 1,000,000,000,000,000,000,000 stars. Given that the only system humankind has studied contains at a minimum 3 planets minimally capable of sustaining some form of life, and the continuous discovery of planets around the majority of these stars.....

I would say you have to take into account the likelihood of planets existing in the optimal range (think venus to mars) for water to not be completely frozen, but still remain.

Then the planets themselves have to be of a certain size. There are many variables, but to answer your question.

What would be the chance that the Earth is unique in harboring lifeforms?

I would say considering the necessary building blocks for life are floating out in dead space (amino acids, etc) the chances that life is unique on Earth is much less than the chances that life could occur elsewhere. But we're talking about meaningless numbers out to the decimal places.

 

[Kandahar]

Our next hypothetical:

Science has placed the observed universal Star Count at appx. 10 to the 21st, or 1,000,000,000,000,000,000,000 stars. Given that the only system humankind has studied contains at a minimum 3 planets minimally capable of sustaining some form of life, and the continuous discovery of planets around the majority of these stars.....What would be the chance that the Earth is unique in harboring lifeforms?

The chances are almost nil.

I think there are more than 3 bodies within our solar system that could potentially harbor life. Besides Earth, we have Mars, Jupiter, Europa, and Titan which are all candidates. There are several others where there is a remote possibility.

Personally I doubt that life is very rare at all. When Earth settled down after its chaotic early days and became capable of sustaining life, life began almost immediately. This suggests to me that it probably wasn't a freak accident.

I tend to lean toward the viewpoint that where the conditions for life exist, it WILL form. It will likely be very different than anything on earth...so different that we might not even consider it "life" at first. Perhaps cells or DNA or sexual reproduction are unique to earth life.

 

[tecoyah]

Have you got any more information regarding the bit where you said "the only system humankind has studied contains at a minimum 3 planets minimally capable of sustaining some form of life" I hadn't heard that before.

"Water or ice? Liquid or slushy or frozen solid? Ever since the Voyager spacecraft missions flew through the Jupiter system in 1979, planetary scientists have wondered about the layer of ice surrounding the second moon of Jupiter.

Europa's ice surface makes it one of the brightest, and smoothest, objects in our solar system.

Recent Galileo spacecraft images have provided evidence that Europa had a liquid ocean underneath the frozen crust sometime in its history, but it is not clear if this ocean still exists. Of the various explanations proposed by scientists, most scenarios of Europa's evolution have the water layer freezing solid earlier in its history. The moon's surface is -260° F, which could freeze an ocean over several million years. But scientists think that the warming caused by a tidal tug of war with Jupiter and neighboring moons could be keeping large parts of the ocean liquid.

The Latest Scoop: A Second Moon with Ocean?
Jupiter's second largest moon, Callisto, may have a liquid ocean tucked under its icy, cratered crust, according to scientists studying data gathered by NASA's Galileo spacecraft.

The Galileo findings, to be published in the Oct. 22 issue of the journal Nature, reveal similarities between Callisto and another of Jupiter's moons, Europa, which has already displayed strong evidence of a subsurface ocean."

Astrobiology is the search for life on other worlds. As unbelievable as that might sound, theoretically all you need for life is organic components, (molecules with both carbon and hydrogen) an energy source, and water. (preferably liquid water) None of these things are overly rare, so some scientists believe that life could actually be very common throughout the universe. In fact, there are several worlds inside our own solar system that have several of these three components, and are therefore suspected of harboring living creatures.

While life itself may be a common occurrence, multi-celled organisms are probably not. Most of our current astrobiological expeditions do not actually leave the planet, instead they study extreme environments on Earth that may be similar to those on other worlds. It was previously believed that no life could life in areas toxic to us, or under the pressure of the ocean’s water, or in extremely hot areas, yet on earth we have found an abundance of single celled bacteria in such places. But while those single celled organisms, called extremophiles, may thrive in their environments, it is very unlikely that multi-celled organisms could evolve there.

It was also previously believed that the only place life could exist was in a solar system’s habitable zone, an area around the star that is close enough that a planet orbiting at this distance to get a good supply of energy, but is far enough that it will not be scorched by the star. Also, it is the distance where water can exist in a liquid state. However, contrary to previous belief, radiation from a star is not the only possible sufficient source of energy. Some worlds in the outer solar system have their own energy sources, which may be enough to support life. The habitable zone is the best place to look for life, but it is no longer believed to be the only possibility.

Saturn’s moon Titan, despite being far out of the habitable zone, is ranked among the most likely worlds in the solar system to support single celled organisms."


Life on Europa
Life on Titan


A couple of the many sites out there