When a huge asteroid crashed into the Gulf of Mexico 66 million years ago – was it alone? Such a question recently arose before scientists when they found a second similar crater on the other side of the Atlantic Ocean.
The crater that indicates the companion of the dinosaur killer is slightly smaller. Called Nadir Crater, it lies on the ocean floor at a depth of 300 meters 400 km off the coast of Guinea (West Africa). The diameter of the crater is 8.5 km, so it could have been created by an asteroid a little less than half a kilometer in size.
A British scientist found a crater hidden under water while studying seismic data. He was looking for a better place to drill to understand past climate changes on Earth. Such studies record different layers of rocks and sediments underground, often at a depth of several kilometers.
“I’ve never seen anything like this. Nadir’s shape is diagnostic of an asteroid impact. It’s got a raised rim surrounding a central uplift area, and then layers of debris that extend outwards,” says the scientist.
According to scientists, the impact of such an asteroid could cause a kilometer-high tsunami and an earthquake with a magnitude of about 6.5. This is much less destruction than what a “dinosaur killer” asteroid could cause. For comparison, it had a diameter of 12 km and formed a depression 200 km wide. Its fall caused powerful earthquakes, tsunamis, and storms.
The idea that more than one asteroid fell on Earth at that time is not new. Some scientists also suggest that the Bovty depression in Ukraine may also be connected with the crater of the Gulf of Mexico. Its age is about the same.