American researchers have a new theory of how an object hit Earth and caused the dinosaurs to die.
Scientists usually agree on where the consequence happened about 65 million years ago. They say a huge object hit an area off the coast of what is now Mexico. Astronomers have said that the most likely cause of the attack was one asteroid or a comet
In recent years, researchers have provided evidence that the impact was caused by an asteroid. The theory suggests that the asteroid came from an area between the orbits of Mars and Jupiter.
But a study by two Harvard University astronomers presents a new theory: that the crash was caused by a comet. The researchers say the comet comes from an area of ice debris on the edge of the solar system. The area is known as the Oort Cloud.
Their theory holds that the comet was pulled into the solar system by the gravity of Jupiter. The comet then came very close to the sun, of which tidal force caused it to fall apart. The researchers believe one of the pieces crashed at the place scientists identified in Mexico.
The team based its theory on a model created to predict the likelihood that a long-period comet from the Oort cloud would hit Earth. Long-period comets take over 200 years to orbit the sun.
Since comets come from frozen parts of the outer solar system, they are ice colder than asteroids. They are known for leaving long traces of gas and dust as they melt.
The new study was recently published in Scientific reportsThe lead author was Amir Siraj, an astrophysics student at Harvard. “Jupiter is so important because it is the most massive planet in our solar system,” he told the French news agency AFP.
Siraj said the findings showed that Jupiter’s profound influence “pushes these incoming comets into orbits over a long period of time that bring them very close to the sun.” The comets experience such a strong tidal force from the sun “that the most massive would break up to about a thousand fragments, ”he said. Any of those fragments would be big enough to make one crater the size of the Mexican site, he added.
That huge impact is estimated to have equaled the power of about 10 billion atomic bombs. The US space agency NASA has estimated that the attack created a huge crater about 180 kilometers wide and 900 meters deep.
The event is believed to have triggered major wildfires, earthquakes and ocean waves. Chemicals were also released into the atmosphere, which led to a strong cooling. Scientists blame the event for destroying more than 70 percent of plant and animal life. In addition, all dinosaurs that were not bird-like became extinct.
The researchers say their theory could be tested by further studying the crater in Mexico, and possibly the one on the moon. In addition, space explorers can also be sent to collect comet material for research.
The study also suggests that similar effects are expected to strike Earth about once every 250 to 730 million years. But the project’s other lead researcher, Harvard professor Avi Loeb, noted that this is only an estimate.
“You never know when the next one will come,” he said. “The best way to find out is to search the sky.”
I am Bryan Lynn.
Bryan Lynn wrote this story for Learning English, based on reports from Agence France-Presse and The Harvard Gazette. Mario Ritter, Jr. was the editor.
We want to hear from you. Write to us in the comments section and visit our Facebook page
Quiz – Scientists have a new theory of what killed the dinosaurs
Start the quiz to find out
Words in this story
consequence nAn act or event where something hits another thing
asteroid n. a space rock, which can be small or the size of a large moon, revolving around the sun
comet nAn object in space made of material such as gas and ice that is left in its orbit as it approaches the sun
debris n. pieces that remain after something has fallen apart
tidal force nA secondary force of gravity between two objects
break vTo suddenly break into many pieces
fragment nA broken piece of something that was once bigger
crater nA round hole created by an explosive force, such as a bomb or an object falling from the sky