An international team led by UCL scientists have discovered evidence for the oldest forms of life on earth so far. The discovery indicates that the discovered life lived about 3,770 and 4,300 billion years ago, while planet earth is 4,500 years old. The researchers published their work in Nature under the title ''Evidence for early life in Earth’s oldest hydrothermal vent precipitates.''

Earliest life on earth

In Quebec, Canada, scientists have found specific kinds of filaments and tubes that are only produced by bacteria feeding on iron, these materials were found on one of the oldest rocks that existed on planet earth, these rocks only existed between 3,770 and 4,300 billion years ago, such rocks also indicate that early earth contained high amounts of iron.

The earliest form of life was discovered before in Austrailia which dated about 3.5 billion years ago, but some scientists suspect that such evidence had not been produced by any life form, rather produced by pure chemistry.

The researchers of the current research wanted to make sure that their discovery was caused by biological micro-organisms, so they applied a systematic test to make sure that what they found was not just a result of heat and pressure, and they finally ruled out any such possibility and demonstrated that it was caused by biological micro-organisms. What the researchers were investigating is an iron-oxide element called haematite, this element is produced by iron-eating bacteria that live until today.

Doubts on origin of life theories

The Origin Of Life is still an unsolved mystery in science today, even the simplest single cell bacteria is exceedingly complicated that it is impossible to had been formed by chance.

Scientists have been proposing theories for the origin of life by proposing life forms that existed before the very first cell, they proposed theories like the RNA world and metabolism first worlds, but all of these theories are far from being complete.

The current discoveries indicate that life emerged at least 3.8 billion years ago, and the age of earth is only 4.5 billion years old, such a fact casts doubts on all pre-life scenarios since they all propose countless life forms evolving for many millions or even billions of years to reach the simplest cell that we find today.

It is also important to note that earth needed very long time after its formation to be able to sustain proper chemistry for life, earth was a very violent place on its early days.

Matthew Dodd, one of the researchers said: "These discoveries demonstrate life developed on Earth at a time when Mars and Earth had liquid water on their surfaces, posing exciting questions for extra-terrestrial life. Therefore, we expect to find evidence for past life on Mars 4,000 million years ago, or if not, Earth may have been a special exception."