Primeval Earth was regularly struck by city-size asteroids during its first several billion years, this was a time of creation and destruction. At this point, these impacts may have a direct influence on the creation of life on the earth, or it could have been a planet without the life it has now. 

This period in the planet's history, about 2.5-3.5 billion years ago had city-sized asteroids striking its surface like clockwork, at a 15-million-year interval. This period might have seen the rise of animals and plants which became extinct.

It changes initial ideas of how terrible was the planetary impacts were in this critical period. According to the Southwest Research Institute, this onslaught was theorized in their latest hypothesis.

What happened in the 2.5-3.5 billion years has determined the present-day earth and the life that inhabits it now. No one knows what changes will follow or if they can be stopped.

Cataclysmic planet killers?

One speculation is the asteroids striking the earth's surface are more gargantuan than what killed the dinosaurs, which is supposed to be seven miles wide. Earlier than 65 million years- ago (MyA) larger space rock shattered the earth's surface many times, reported the Daily Mail.

These primeval craters have long been eroded or destroyed by the passing of time, but remains called spherules or glassed earth from the immense heat might be found.

The formation of these glass remains is by the impact tossing super-hot earth fragments that combined with cooler vapors, instantly forming when they made contact. Earth was regularly struck by city-size asteroids causing this phenomenon.

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Scientists think it how these glass particles are spread out, that big an asteroid will have more spherules seen in an area. So, more glass particles in a wide expanse mean more impact forces hitting the earth's surface.

A new model proposed for an asteroid impact

According to Simone Marchi, the paper author and physicist from Southwest Research Institute in Colorado. He suggests an impact flux simulation, contrasted with an analysis of ancient spherule layer data, noted UK Alert Breaking News.

The present models of early impacts on earth are insufficient and do not account for all asteroid hits, indicated by spherule layers. It might be the impact flux is more than 10 times than estimated before.

Dr. Marchi added that in between 3.5-2.5 billion years ago, the impact was as big as the Chicxulub asteroid, but every 15 MyA on the cosmic clock. Planets colliding with asteroids is part of the earth's formation process.

Though destructive, these cosmic collisions had a part in the creation of oxygen. But periodic impacts have an effect on whether it would be plentiful or not.

The next part according to the scientist is studying the connection of oxygen evolution via the successive impacts, to the creation of the first creatures billions of years ago.

Geologist Rosalie Tostevin, from the University of Cape Town in South Africa, added that impacts would have disrupted something, she was not part of Dr. Marchi's study, noted Phys Org.

She lamented that few samples exist until now and that lack of proof makes the conclusions incomplete. But the updated simulations of Marchi can explain these large impacts of primeval earth.

As for the rise of oxygen 2.5 billion years ago (ByA), a small amount existed in agreement with the author of the study. Tostevin added that Earth was regularly struck by city-size asteroids that could be another for evolved life and oxygen in the atmosphere.

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