Saturday, November 28, 2009

Possibilities for Extraterrestrial Life

Shivantha Withanage

Is there any kind of life out side of the earth? This is a question to everyone. Some people say there could be life outside of our planet and some say there couldn’t be life in any other place in universe other than earth. There are reasonable facts for both answers. But no one has proved them.

Universe is an infinite space. We have to believe it because we are still unable to travel through the whole universe. If universe is infinite, there could be many galaxies. Most of them may be even larger than our galaxy, the Milky Way. So there could be so many solar systems and also many planets. So how can we say that there are no such planets like earth in this universe? There is a huge possibility of having those kinds of planets. If those planets have water, minerals, temperature that is suitable for life and an atmosphere with sufficient gases there could be life on them.

According to human knowledge there is a temperature range that is precise for living beings and there are basic elements which can form living bodies. There are also some gases that living animals can use for breathing and some energy sources which can use as energy supply for living bodies. But all these are limits followed by present human knowledge about life. Why couldn’t be there a life which is entirely different from the life on earth?

People believe that carbon is the best element for living structures. But silicon can be a good alternate element for that. Carbon and silicon belong to the group IVA in the periodic table and elements belong to the same group have similar natures. So it could be possible of having living bodies made of silicon. Scientists had already found animals consisting silicon, in the earth. Diatoms that belong to the phylum Chrysophyta are photosynthetic, unicellular organisms with unique double shells made of opaline silica which are often characteristically marked. So they are called as the jewels of the living world.

Oxygen is considered as the breathable gas for most of the living beings on earth. Living bodies are designed to generate ATP (Adenosine Tri Phosphate), the compound which can store energy of chemical compounds such as glucose, amino acids and lipids. The energy in those compounds is transferred to ATP through a process happen inside the mitochondrion of live cells. Oxygen is the molecule that catches the last hydrogen atoms released by this reaction series. Oxygen acts as the dehydrogenator in this process. There could be molecules instead of oxygen, which are capable of combining with the last hydrogen atoms. We should remember that we have found only a little amount of elements. So there could be many elements in this planet that are not recognized or found yet. In the universe there could be more. We will never find most of those elements in earth. Some of those elements could form a molecule that can efficiently catch the last hydrogen atoms. Therefore oxygen could not be the only dehydrogenate molecule.

When we take the temperature range that is considered as suitable for life in to account, we get the same results as carbon and oxygen. We prefer this is the suitable temperature range for life because we experience it on earth. Temperature range suitable for a living body is selected by the nature, mechanisms occurring inside the body and chemical structure of it. But we should not forget that chemical structures can be varying in different situations. So there can be life in very cold places and also in extremely hot places. Today scientists have found life in cold ice cores and even inside volcanoes. So we have got some evidences even from our world. Therefore, theoretically it is logical to believe that there is life outside of the earth.


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