The crater left behind by the largest meteorite ever to hit Earth has been discovered, after going undiscovered for a century.
Traces of the enormous impact of the meteorite, which struck the planet approximately 790,000 years ago, have been observed across about 20% of the Eastern Hemisphere – one tenth of the entire surface of Earth.
The evidence takes the form of a “field of black glassy blobs” also known as tektites, according to researchers in a recently-published article in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) journal.
“The large crater from which these tektites originated has eluded discovery for over a century, although evidence has long pointed to a location somewhere within Indochina, near the northern limit of the strewn field,” the article says.
The team of researchers now believes the crater, which is about 15km in diameter, is located in Southern Laos.
There’s a good reason why the enormous crater went undetected for so long – it’s buried beneath a 910km young volcanic field.
It was only by studying the tektites – gravel-sized bits of natural glass ejected in the instance of a meteorite impact – that scientists were able to plot out exactly where the meteorite hit our planet.
Once the site had been identified, the team conducted field gravity measurements to detect if there was a “gravity anomaly” which would indicate the presence of a huge hidden crater. Sure enough, an anomaly was discovered.
The implied presence of “young, weathered” pieces of basalt rock at the location and time of the meteorite impact, as well as an outcrop of crudely layered sandstone and mudstone some 10 – 20km from the centre of the impact, both support the research team’s theory that the impact of the biggest piece of outer space debris to ever strike Earth has been discovered.