SCIENTISTS have claimed the first life on Earth emerged 100 million years earlier than previously thought.

A team of researchers have used genetic data rather than palaeontology, the study of fossils, in a bid to try and date the beginnings of life on earth.

They have focused on a period known as the late heavy bombardment, when our planet came under intense meteor attack about 3.9 billion years ago.

The research was conducted by a team made up of scientists from the universities of Bath and Bristol and published in the journal Nature Ecology and Evolution.

Using the genetic data available they were able to trace a “last universal common ancestor” - a hypothetical single cell from which all life on Earth descended - to before the late heavy bombardment.

That is “significantly earlier than the currently accepted oldest fossil evidence would suggest” for when life began, which is between 3.5 billion and 3.8 billion years ago, said one of the researchers, Holly Betts.

Writing in the magazine The Conversation, Ms Betts, who is studying for a PhD at Bristol university, said the team decided to approach the construction of a timescale for life in a new way.

“This involved using the wealth of genetic data that we now have for organisms living today and applying a molecular clock a method to decipher the past by reading the stories written in the genes of living organisms.”

She explained that the study combines the molecular data of 29 genes from a total of 102 living organisms to arrive at their conclusion.

They included bacteria, single-celled micro-organisms known as archae as well as plants and animals.

About 4.5 billion years ago, the Earth collided with a smaller planet scientists have called Theia.

The enormous explosion resulted in the formation of moon and the heavy iron core at the Earth's centre.

Though the blast would have "sterilised" the plant, out the impact life began to form.

“Science may have enabled us to travel in space and trace the history of the entire universe, but it has not yet been able to answer exactly how and when life first arose on our planet," said Ms. Betts.

“Traditionally, scientists have used the fossil record to try to answer these questions.

“Yet, as palaeontologists are all too aware, fossils are increasingly hard to find as we move backwards in time.

“We hope that our study will be a good starting point for probing the mysteries of evolution at this extremely early time in Earth’s history.”