The asteroid that created the Nadir crater measured around 450-500m wide, and scientists think it hit Earth at about 72,000km/h.
The nearest humans have come to this scale of event was the Tunguska event in 1908 when a 50-metre asteroid exploded in the skies above Siberia.
The Nadir asteroid was about the size of Bennu, which is currently the most hazardous object orbiting near Earth.
Scientists say the most probable date that Bennu could hit Earth is 24 September 2182, according to Nasa. But it is still just a probability of 1 in 2,700.
There has never been an asteroid impact of this size in human history, and scientists normally have to study eroded craters on Earth or images of craters on other planets.
To further understand the Nadir crater, Dr Nicholson and team analysed high-resolution 3D data from a geophysical company called TGS.
Most craters are eroded but this one was well-preserved, meaning the scientists could look further into the rock levels.
“This is the first time that we’ve ever been able to see inside an impact crater like this – it’s really exciting,” says Dr Nicholson, adding there are just 20 marine craters in the world but none have been studied in detail like this.
The findings are reported in Nature Communications Earth & Environment.
