The asteroid that hit the Gulf of Mexico and wiped out the dinosaurs had a companion? Did a second meteorite land that day? Off West Africa, scientists uncovered a 9-km crater generated around the same time as Chicxulub. This raises doubts about whether the new crater is connected to the one that killed the dinosaurs.

Large asteroid hit Earth 66 million years ago. The crash triggered a calamity that killed 75%. Wildlife species. The cosmic rock slammed Earth like 10 billion Hiroshima bombs. It triggered forest fires and a global tsunami. Massive quantities of sulfur were thrown into the sky, obscuring the sun’s beams and causing global cooling. These events transformed the globe.

Chicxulub impact crater was formed 66 million years ago. Off West Africa, researchers have found a crater identical in age to Chicxulub, raising doubts about whether Chicxulub’s asteroid had a relative. Or maybe the new crater was produced by a cosmic rock that wiped out dinosaurs and other animals.

Nadir was named after the neighboring Nadir Seamount volcano. Chicxulub is bigger. It’s 8.5 km in diameter, compared to 150 km for Chicxulub. Still, it’s a catastrophe. According to specialists, the forming rock was less than 500 meters across.

The new crater located 400 km off the coast of Guinea, West Africa. It was found through studying the seafloor and ancient strata.

Unexplored crater. To show that it has anything to do with the asteroid that killed the dinosaurs, scientists will have to dig into the structure and identify materials created under great pressure and high temperatures.

The crater’s morphology implies alien origin, says David Kring of the Lunar and Planetary Institute, who discovered it. “The crew found what looks like an impact crater. There are few impact craters remaining on Earth. Each one we locate gives a fresh window into their geological processes and influence on Earth’s biological development, said Kring.

Nadir crater originated about the same time as Chicxulub, suggesting they may be connected.

When Uisdean Nicholson and his colleagues looked at seismic mapping data off the West African coast, they didn’t seek for space rock strikes. In 100 million years, South America and Africa were separated by tectonics.

Ships deliver a signal to the seafloor and capture its reflection for these surveys. The dataset depicts the subsurface structure. The data indicated an unusual dip in the rock strata under the bottom, hidden by 300m of silt in 900m of water.

Researchers spotted an 8.5-kilometer-wide round or oval hole. The formation has elevated edges and spewed debris outside the crater. University of Arizona’s Veronica Bray models it as a 400-meter asteroid crash (the rock responsible for the Chicxulub crater was about 10-13 km in diameter). Chaos beyond the crater floor suggests debris expelled after the crash.

The authors are fairly certain that this finding is an impact crater. Other mechanisms that might generate a crater include the collapse of an undersea volcano or the eruption of subsurface gas. Neither option fits the crater’s geology or shape.

After defining the crater, researchers constructed computer models to describe the asteroid and the collision. A 400-meter-diameter asteroid impacting an 800-meter-deep ocean best fits the crater’s form.

Scientists estimated the asteroid impacted the ocean bottom with 5,000 megatons of TNT and caused a 10-km flame. This instantly evaporated water and rock. The collision likely created a magnitude 7 earthquake, undersea landslides, and a tsunami. This only affected the nearby area. Global extinction wasn’t caused.

Nadir Crater originated about the same time as Chicxulub, 66 million years ago. The researchers believes it was produced by a chunk of the Chicxulub asteroid. If a rock broke off before impact, the two craters would be close. Nicholson indicates gravity tore the asteroid apart as it reached Earth, causing two crashes days apart. If true, the second blow may have amplified Chicxulub’s impacts.

Shoemaker-Levy was blasted apart by Jupiter’s gravity in 1992 and impacted the planet in 1994. In six days, 21 pieces struck Jupiter. Chicxulub crater’s cosmic rock may have fragmented. Other impact craters may be destroyed by tectonics or haven’t been found. Both craters may have originated from the same parent asteroid that broke apart in the asteroid belt and hit Earth in a salvo spanning hundreds of thousands of years.

Not all scholars believe Nadir Crater caused the dinosaur extinction. New crater date is questionable. Nicholson and his colleagues can estimate Nadir Crater’s age to within 800,000 years, thus the two crashes may have happened at different times and had nothing to do with each other.