The researchers said that asteroids the size of a city fell to Earth much more often than previously thought. They constantly influenced the development of the planet.
Scientists noted that every 15 million years, our planet was hit by an asteroid about the size of a city. During this turbulent period, which occurred about 2.5-3.5 billion years ago, the planet regularly experienced shocks, and the chemical composition near its surface underwent dramatic changes that can be traced in rocks on the Earth’s surface even now.
In this study, Simon Marchi, chief researcher at the Southwest Research Institute, drew attention to the presence of so-called spherules – small bubbles of evaporated rock that were thrown into space with each impact of an asteroid, but then froze and fell back to Earth, forming a thin layer. which geologists see in rocks.
The team developed a new method for simulating the effects of asteroid collisions in terms of their ability to generate spherules and influence their distribution. The larger the asteroid, the thicker the layer of spherules in the rock should be. But when the researchers looked at the actual number of spherules in different layers of the rock and compared it with current estimates of past asteroid impacts, they found that the two values were not the same.
“We have found that current models of asteroid impacts on Earth greatly underestimate the number of impacts recorded on the layers of the spherules. Between 3.5 and 2.5 billion years ago, the actual flow of impacts could have been 10 times higher than previously thought, ”the researchers noted.
These past asteroid strikes could also affect oxygen levels and the young planet’s ability to support life.