Vredefort Crater Much Larger Than Originally Thought
New geological evidence finds that Vredefort crater in South Africa was originally 250–280 kilometers in diameter and formed by an object 20–25 kilometers wide.
When we talk about planetary defense, especially in the context of the DART mission, mass extinction events — such as the Chicxulub impact — tend to come up in conversation. That particular event involved an impactor about ten kilometers in diameter which left a crater 180 kilometers across. Not only did the dinosaurs die off, other global effects included atmospheric heating, forest fires, acid rain… basically global devastation. Hence the importance of the DART mission.
It’s easy to focus on that one single event as being a reason to work toward planetary defense, but Chicxulub was by far not the only impact or even the largest. That designation goes to the Vredefort crater in South Africa, which up until recently, was thought to have been formed by an object measuring 15 kilometers in diameter. Now, in a new paper published in the Journal of Geophysical Research: Planets and led by Natalie Allen, computer simulations based on new geological evidence have upped that estimate to between 20 and 25 kilometers.
