For several decades it has been believed that life originated on the earth billions of years ago in soups of water and chemicals which interacted with energy from the Sun. This would make the formation of life an improbable event.
However, a number of scientists, including the present author (Sidharth, 2009, Journal of Cosmology Vol 1, Vol 10.) have been arguing for a dual mode origin of life, that is key ingredients like amino acids, but not yet fully formed life had reached Earth from outer space and chemically interacted with other ingredients present to form life.
As similar conditions could have taken place on other planets, this would mean that the formation and evolution of life may be far more probable than thought earlier, particularly on planets located in habitable zones.
For example, complex molecules have been discovered in interstellar space, for example, in the cool dust clouds of the Orion Nebula and in the constellation of Sagittarius.
Observations with telescopes, spectroscopes, radio telescopes and even orbiting observatories have confirmed the presence of molecules like methyl cyanide, water vapour, formaldehyde, methyl alcohol and even the potable ethyl alcohol.
Clearly there are several organic molecules in the cool dust clouds spread across outer space.
