Study finds asteroid impact on Earth and Moon

Guwahati: According to a study, the number of asteroid impacts on the Earth is increased by two or three times starting around 290 million years ago.

Sara Mazrouei from the University of Toronto in Canada said that the research provides evidence for a dramatic change in the rate of asteroid impacts on both the Earth and the Moon that occurred around the end of the Paleozoic era. She further added that the implication is that since that time we have been in a period of relatively high rate of asteroid impact that is 2.6 times higher than it was prior to 290 million years ago.

Moreover, It has been assumed previously that most of the Earth's older craters produced by asteroid impacts have been erased by erosion and other geologic processes. An associate professor at the University of Toronto Rebecca Ghent also said that the relative rarity of large craters which is older than 290 million years and younger than 650 million years is not because we lost the craters but because of the impact rate which is lower than the present time.

It was since decades that scientists tried to understand the rate that asteroids hit Earth by using radiometric dating of the rocks around them to determine their ages. Scientist believed that as erosion caused some craters to disappear, it is difficult to find an accurate impact rate and determine whether it had changed over time. One way to avoid the problem is to examine the Moon which is hit by asteroids in the same proportions over time as Earth.

Rocks radiate much more heat than fine grained soil called regolith during the lunar night which allows scientist to distinguish rocks from fine particles in thermal images. The team then calculated the ages for previously un-dated lunar craters.

The researchers found that the two bodies had recorded the same history of asteroid bombardment when compared to a similar timeline of Earth's craters.

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