How do we know - when we know so little?

Relative to the size of the universe, planet earth is like a grain of sand in the Shara desert. However, planet earth, in the universe is unique--for as far as we have been able to learn--we are the only planet, at least in our universe, that we have been shown that it can sustain life/mankind. Our planet is also unique in that our make-up is 20 percent land/earth and 80 percent water. In this regard, there is a few things now evident that shows we are a major part in the empire of the sun, and of the planets that has become so dependant on the qualities of our way of life. The Sun is our planets only source of light and heat, in the quantities needed to maintain life as we know it--on our planet. What we do know is that the Sun is one hundred times the size of planet earth. That Earth is 93,000.000 miles from the Sun. Its heat source is so powerful that a grain of Sun the size of a pinhead, could burn a man to death from a thousand miles away. In short there is nothing on earth, in regards to heat, comparable to such a great power/heat capacity when compared to the Sun What we know about our solar system, is that it was created from what is best known as the Big Bang theory, about l5 billion years ago. While in the universe, earth is only 4.6 billion years old. However, the fact that we are now living on planet earth we sould be grateful for it, that we are still the only planet in our univre capable of sustaining life. Also, it is the only planet that is considerd a self-cleaning planet and over billions of years, has met the challange of self presevation. Still, there are those amongst use that claim we are destroying this planet. Ah yes, us little bitty people, that are about 4,000.000 years into the develpment process could be the only creatue that could cause our planet to self-destruct. For that matter, man is still in its development state/stage, so how have we acquired this greeat power so soon, to destoy the planet through our own making. I SAY THIS IS SILLY. HOW DID WE EVER COME TO THIS CONCLUSION: To my knowledge, and to date, as far as I can discern, we have no way of Knowing how to do so. IN SHORT, IN THE REALM OF EARTH SCIENCE, NOTHING HAS BEEN ESTABLISHED OR QUANTIFIED TO WHAT PART OF THE EARTHS MASS CONSIST OF SUCH AND SUCH AND IF WE GET TWO MUCH OF SUCH, INTO THE ATMOSPHERE, IT WOULD DESTROY US. FOR EXAMPLE WHAT IS THE SIZE/MASS OF EARTHS ATMOSPHERE, RELATIVE TO THE SIZE/MASS OF THE PLANET EARTH. WITHOUT KNOWING THIS, HOW CAN WE DETERMINE WHAT IS TO MUCH OF ANYTHING--LIKE THE AMOUNT OF CARBON WE PRODUCE, RELATIVE TO ITS QUANTITY IN THE ATMOSPHERE AND WHEN WILL WE EXCEED THAT PARTICULAR QUANTITY OF CARBON, THAT WOULD CAUSE US TO HEAT UP THE PLANET TO THE POINT OF DESTRUCTION. TO MY KNOWLEDGE NONE OF THIS HAS BEEN ESTABLISHED. IN OTHER WORDS TO MUCH CARBON COMPARED TO WHAT AMOUNT, BEFORE IT BECOMES TOXIC HAS NOT BEEN ESTABLISHED. THERE IS MUCH YET UNKONW/UNQUANTIFIED TO REACH ANY CONCLUSIONS RELATIVE TO THIS MATTER. ONLY A FOOL OR A MAN WITH A PARTICULAR AGENDA WOULD BUY INTO THIS CRAP! OOPS--BIG AL MIGHT BE THAT FOOL! The Messenger