Scientists say second killer asteroid may have hit Earth

Scientists have been investigating the possibility for a second asteroid hit Earth at about the same time as what is believed to have killed off nearly all dinosaur life.

The investigation is linked to a smaller crater recently discovered in the ocean. Researchers say the crater may have been created by a large asteroid.

Scientists have long believed that a large asteroid hit Earth about 66 million years ago near Mexico’s Yucatan Peninsula. They estimate that the force of the collision is equal to the force of about 10 billion nuclear bombs.

The impact, or impact, is believed to have caused widespread fires, earthquakes and large ocean waves or tsunamis. Scientists also believe the event caused a release of chemicals into the atmosphere that led to severe cooling.

Climate change is blamed for causing the extinction of more than 70 percent of plant and animal life. All dinosaurs that weren’t like birds died out.

This impact created a large crater about 180 kilometers wide and 900 meters deep.

Researchers say the newly discovered crater, found in the North Atlantic Ocean, is much smaller. It is about 8.5 kilometers wide. It is buried up to 400 meters below the seabed off the coast of Guinea, West Africa.

Scientists found the crater using seismic instruments. Such instruments are designed to measure earthquakes and detect others vibration signals on Earth.

The crater was discovered by Uisdean Nicholson, a geologist at Heriot-Watt University in Edinburgh, Scotland. At the time, Nicholson was working on an ocean mapping project involving seafloor spreading. This type of spreading is what caused the African and American continents to separate over time, leading to the formation of the Atlantic Ocean.

“I have interpreted a lot of seismic data in my time, but I had never seen anything like this,” Nicholson said in a statement. He added that he was surprised to see that the data described a large crater “with very unusual characteristics.”

Nicholson said the crater has several features that suggest it may have been created by an asteroid. But he noted that researchers will need to investigate further before this theory can be confirmed. A team plans to visit the crater to drill into the seabed and collect minerals samples.

The team’s findings were recently reported in a study in Pub Advances in science.

Veronica Bray is another member of the research team. She is a planetary scientist at the University of Arizona. Bray used a computer simulation to predict the effects such an impact would have had.

Simulations suggested that the crater was created by a 400-meter asteroid that crashed into 500 to 800 meters of water. She said this would likely have triggered a 900-metre-high tsunami as well as a 6.5-magnitude earthquake.

Bray noted that the effects of the newly discovered crater would have been far less than the one that hit present-day Mexico. But he would still have added “significantly” to local destruction. She said the new discovery makes her wonder if there are other impact craters that scientists have yet to find.

Nicholson said his team has considered the possibility that the two impact craters could be connected. Researchers said they believe the newly discovered crater may have been formed by the breakup of a parent asteroid.

Sean Gulick is a crater impact expert at the University of Texas at Austin. He called the finding an “exciting” discovery that could lead to further investigations of other possible impacts around the same time period.

“Despite four billion years of impacts hitting Earth, only 200 have been detected,” Gulick said in a statement. “So it’s exciting news any time a new potential impact is discovered, especially in the hard-to-explore (ocean) environment,” he added.

I’m Bryan Lynn.

Bryan Lynn wrote this story for VOA Learning English, based on reports from Heriot-Watt University, University of Arizona and advances in science.

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The words in this story

asteroid n. a rocky object that orbits the sun like a planet

vibration n. a shocking move

interpret c. to explain exploring the meaning of something

FEATURES n. a typical or noticeable quality that makes a person or thing different from others

sample n. a small amount of something that gives you information about the thing from which it was taken

the simulation n. a creation of something that behaves or looks like something real but is not

significantly adj. important or obvious

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