Biggest Crater

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You can’t just ask where is the biggest crater. You need to ask: “Where is the biggest crater on Earth and in the solar system?” to get a complete answer. Even then there is a little controversy to be had. The Vredefort Crater is the largest verified crater on Earth, but the Wilkes Land crater is larger. Wilkes Land has not been verified at this time. So, you can see where there is a slight amount of controversy. Not much, but enough to let debate rear its head.

The Vredefort Crater is 300 km in diameter and 5 km deep. It is thought to be 2 billion years old. Vredefort is located in South Africa. Erosion had taken a large portion of the rim, but there is a visible ring that can be seen from space. The asteroid that created the crater turned up rock from as deep as 20 km under the Earth’s surface. There is a small dome at the center of the crater. That dome misled researchers early on, making them think that the crater was formed by a volcanic event. Vredefort crater has multiple rings showing from the impact. The effects of erosion have erased many of those rings.

Wilkes Land crater is 500 km in diameter and is located in Antarctica under a sheet of ice that is 1.6 km thick. Because of the ice, samples are not available to verify the crater as being formed by an asteroid. Future technology may allow samples to be taken. Until then the Vredefort Crater will reign as the king of all asteroid craters.

According to Nature magazine, Mars has the biggest crater in the solar system. It is believed that the red planet was hit by an asteroid the size of our moon early in its development. That asteroid impact left a crater that takes up most of the planets northern hemisphere. Scientists have known about the impact crater for many years, referring to it as the Borealis Basin. It originally was thought to be a volcanic cataclysm. Thanks to the detailed geologics from the Mars Reconnaissance Orbiter and the Global Surveyor, scientists have been able to conclude that it is actually an impact crater.

While there may still be some controversy about future findings. The current reigning king of biggest crater on Earth is the Vredefort Crater and the undisputed champion biggest crater in the solar system is the Borealis Basin on Mars.

There are some interesting articles from NASA and other internet sources along with a related article here on Universe Today.

References:
NASA: Asteroids
Wikipedia