Approximately every 15 million years, our evolving planets will be hit by rock fragments as large as cities, or even larger states, new research scientists say. statement.. The study was presented at this month’s Goldschmidt Geochemistry Conference.
Researchers say that during this fierce period, 2.5 to 3.5 billion years ago, the planet shook regularly, chemicals near its surface changed dramatically, and can still be tracked by rocks on the ground today. Said. ..
In this study, Simon Marchi, the chief scientist at the Southwest Institute in Boulder, Colorado, and his colleagues were so-called. sphereThe small bubbles of vaporized rock that were thrown into space at each asteroid collision, but then solidified and returned to Earth, form the thin layers that geologists see in today’s bedrock.
The team has developed a new method for modeling the effects of asteroid collisions in terms of their ability to generate asteroids and influence their global distribution. The larger the asteroid, the thicker the rock asteroid layer should be. However, when researchers examined the actual amount of spheres in different layers of the bedrock and compared them with current estimates of past asteroid collisions, they found that the two values did not match.
“We found that the current model of the Earth’s early bombing significantly underestimates the number of known effects recorded by the sphere layer,” Marqui said in a statement. “The true impact flux could have been up to 10 times higher than previously thought in the period 3.5-2.5 billion years ago.”
Those past asteroid strikes may also have had an impact Oxygen level And the ability of young planets to support life.
“We have discovered that oxygen levels would have fluctuated dramatically during periods of intense shock,” Marqui said. “Given the importance of oxygen to the development of the Earth, and in fact the development of life, the potential for collisions is interesting and worth further investigation. This is the next step in our work.”
According to Rosalie Tostebin of the University of Cape Town, who was not involved in the study but specializes in ancient geology, some chemical markers were found in the early atmosphere before a permanent rise in the surroundings. It shows the existence of oxygen “bubbles” in 2.5 billion years ago.
“There is considerable debate about the importance of these whims and whether they actually happened,” Tostevin said in a statement. “We tend to focus on the evolution of the Earth’s interior and life as a control of the Earth’s oxygen balance, but rock bombing from space provides an interesting alternative.”
A rocky body without an atmosphere like the moon carries details Records of past asteroid collisions.. On planets like Earth, with varying meteorological patterns and geological activity, many traces of past effects have long been erased.It took scientists to discover until the late 1970s Chicxulub collision crater In Mexico. It took them several more years to identify this effect as the cause of the dinosaur extinction.
“These major effects would certainly have caused some confusion,” Tostevin said. “Unfortunately, this long-standing rock has hardly survived, so direct evidence of its impact and its ecological impact is mottled. The model proposed by Dr. Marqui feels better the number and size of collisions. Helps the early Earth. “
City-sized asteroids struck the ancient Earth 10 times more often than expected
Source link City-sized asteroids struck the ancient Earth 10 times more often than expected