We may have determined the hottest temperature ever recorded on the Earth’s surface, and it occurred almost 40 million years ago. Amazingly, researchers have been able to deduce the soaring temperatures reached when a massive chunk of space rock slammed into Canada, vaporizing not only itself, but also the surface as the impact rippled through the crust.
Despite occurring when the monumental Titanoboa was still slithering through forests and whales were starting to evolve in the oceans, the scientists were able to glean what happened immediately after a meteor struck Earth, publishing their results in Earth and Planetary Science Letters. They found that the impact briefly heated the rocks that were struck to a sweltering 2,370°C (4,298°F), which is the hottest temperature ever recorded on the planet.
When rocks are exposed to extreme heat, they can record the event as they change structure. But when a meteor strikes the planet, it more often than not hits at such immense velocity that not only is the meteor blasted into oblivion, but so is the crust it has just collided with.
That means that there is simply nothing left to show from the impact and the incredibly high temperatures reached, apart from the massive hole in the ground that is.
But researchers may have found another way to divine the temperatures reached from these collisions. While studying the Mistastin Lake impact crater in Labrador, Canada, which is an impressive 28 kilometers (17 miles) across and was formed some 38 million years ago, the researchers discovered that the crater was once so hot it was able to turn a common mineral known as zircon into a crystalline mineral known as cubic zirconia.
From this, they were able to deduce that the crater once experienced blistering heat somewhere in the region of 2,370°C, as this is the minimum temperature required to turn zircon in cubic zirconia.
“Nobody has even considered using zirconia as a recorder of temperatures of impact melts before,” Nicholas Timms, co-author of the study, told New Scientist. “This is the first time that we have an indication that real rocks can get that hot.”
By using the mineral, the researchers have been able to understand the temperatures reached by meteor impacts much further back in the history of our planet than thought possible. This could help other understand what happened when Earth first formed some 4 billion years ago, when it was being continually bombarded by space debris, and eventually produced an environment conducive to life.
[H/T New Scientist]