Artist's concept of volcanic activity on the surface of Venus. - stock illustration

Artist's concept of volcanic activity on the surface of Venus. Based upon analysis of the number and distribution of impact craters across the whole of Venus, the entire surface appears to be the same age: about 500 million years old. This is an astonishing result since 500 million years is young for a planet in our solar system. Like the Earth, Venus is thought to be about 4.5 billion years old. This suggests that 500 million years ago Venus completely resurfaced itself, turned itself inside out. What caused such a cataclysmic event, or if indeed this is what really happened, remains a mystery.