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Scientists find link between comet, asteroid showers and mass extinctions

Date:
October 20, 2015
Source:
Royal Astronomical Society (RAS)
Summary:
For more than 30 years, scientists have argued about a controversial hypothesis relating to periodic mass extinctions and impact craters -- caused by comet and asteroid showers -- on Earth. Now scientists have concluded that mass extinctions occurring over the past 260 million years were likely caused by comet and asteroid showers.
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An artist's illustration of a major asteroid impact on Earth.
Credit: NASA

Mass extinctions occurring over the past 260 million years were likely caused by comet and asteroid showers, scientists conclude in a new study published in Monthly Notices of the Royal Astronomical Society.

For more than 30 years, scientists have argued about a controversial hypothesis relating to periodic mass extinctions and impact craters -- caused by comet and asteroid showers -- on Earth.

In their MNRAS paper, Michael Rampino, a New York University geologist, and Ken Caldeira, a scientist in the Carnegie Institution's Department of Global Ecology, offer new support linking the age of these craters with recurring mass extinctions of life, including the demise of the dinosaurs. Specifically, they show a cyclical pattern over the studied period, with both impacts and extinction events taking place every 26 million years.

This cycle has been linked to periodic motion of the Sun and planets through the dense mid-plane of our galaxy. Scientists have theorized that gravitational perturbations of the distant Oort comet cloud that surrounds the Sun lead to periodic comet showers in the inner solar system, where some comets strike Earth.

To test their hypothesis, Rampino and Caldeira performed time-series analyses of impacts and extinctions using newly available data offering more accurate age estimates.

"The correlation between the formation of these impacts and extinction events over the past 260 million years is striking and suggests a cause-and-effect relationship," says Rampino.

Specifically, he and Caldeira found that six mass extinctions of life during the studied period correlate with times of enhanced impact cratering on Earth. One of the craters considered in the study is the large (180 km diameter) Chicxulub impact structure in the Yucatan, which dates to about 65 million years ago -- the time of a great mass extinction that included the dinosaurs.

Moreover, they add, five out of the six largest impact craters of the last 260 million years on earth correlate with mass extinction events.

"This cosmic cycle of death and destruction has without a doubt affected the history of life on our planet," Rampino observes.


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The above post is reprinted from materials provided by Royal Astronomical Society (RAS). Note: Content may be edited for style and length.


Journal Reference:

  1. Michael Rampino et al. Periodic impact cratering and extinction events over the last 260 million years. Monthly Notices of the Royal Astronomical Society, October 2015

Cite This Page:

Royal Astronomical Society (RAS). "Scientists find link between comet, asteroid showers and mass extinctions." ScienceDaily. ScienceDaily, 20 October 2015. <www.sciencedaily.com/releases/2015/10/151020192331.htm>.
Royal Astronomical Society (RAS). (2015, October 20). Scientists find link between comet, asteroid showers and mass extinctions. ScienceDaily. Retrieved August 26, 2016 from www.sciencedaily.com/releases/2015/10/151020192331.htm
Royal Astronomical Society (RAS). "Scientists find link between comet, asteroid showers and mass extinctions." ScienceDaily. www.sciencedaily.com/releases/2015/10/151020192331.htm (accessed August 26, 2016).