how big is the largest known asteroid?
The largest asteroids with an accurately measured mass, due to the fact that they have been (and are being) studied by the probe Dawn, are 1 Ceres with a mass of 939.3Â±0.5Ã10 kg, and 4 Vesta at 259.076Â±0.001Ã10 kg.
And though millionsâin some cases billionsâof years of erosion have made it difficult to determine the exact size of the meteorites, there is a general scientific consensus around the world's largest craters, which mark the largest asteroid impacts. Here are the ten biggest known: 1. Vredefort Crater. Asteroid impact date: Estimated 2 billion years ago. Location: Free State, South Africa. Specs: Also known as the Vredefort Dome, the Vredefort crater has an estimated radius of 118 miles (190 kilometers), making it the world's largest known impact structure.