Question

The orbital region of Earth is known as the Goldilocks region in our solar system where the probability of life to exist is higher than any other regions which may be too hot or too cold. My question: Why did we make such a wild assumption that, for life to exist we need a neither hot nor cold region or there has to be oxygen and water? There might be alien life which require say Plutonium or Mercury to live. So is it like mandatory to have oxygen for life to exist?

Answer 1

You have a very good question. yes, It may be possible that the life may exist in a different form and may sustain through different resources without oxygen.Being Earth be the only planet with life we found so far we assume life requires the conditions we just have now.

Science is not just wild assumptions. It is all about validating hypothesis through proofs. We haven't so far found any proof that life is existing with such harsh (hot, cold etc).Based on our example we know life exists this way.

Oxygen is not necessary to sustain life (not for humans). There are anaerobic bacteria that doesn't need oxygen. And those can live in extreme conditions like hot, cold or toxic environment. there are microbial lifeforms which can survive high HP, low temperature and high pressure environments. GFAJ-1 is a microbe which can survive in arsenic rich waters, the live by extracting phosphate molecules with it’s phosphate binding proteins.

Sometimes some evolution takes place for such organisms so that new species with desirable adaptation evolve in future. but in the condition of earth as of now such evolution is not possible.As we know life is very adaptable but evolution works to wipe out species that cannot adapt to their environment. Science evolution is random, life on another planet would look dis-similar to life on earth.

Oxygen has a lot of special properties that makes it ideal for life. It is a di-radical and hence very reactive, which lets us convert glucose into energy very fast. Living body is complex one with lots of chemical reactions are taking place. For sustainability we need energy that have to be converted from the matter we are consuming. The conversion of matter to energy is highly energetic capable of explode an organism itself so we have to rely on chemical energy to keep reducing our entropy. For that some conditions have to be satisfied in terms of existance.