There is currently no direct evidence or trace of Theia's impact on Earth's surface. Theia is a hypothetical planetary-sized object that is thought to have collided with Earth in the early stages of the formation of our solar system, leading to the creation of the Moon. This collision theory, known as the Giant Impact Hypothesis, suggests that Theia's impact caused significant material from both Theia and Earth to be ejected into space, eventually coalescing to form the Moon.
The immense energy released during this impact would have melted and vaporized the surface of both bodies, making it unlikely for any remnants of Theia or a distinct crater-like scar to exist on Earth today. Over billions of years, geological processes such as erosion, tectonic activity, and volcanic activity have further reshaped Earth's surface, potentially erasing any remaining evidence of the ancient collision.
While no direct evidence of Theia's impact has been found, scientists have gathered supporting evidence for the Giant Impact Hypothesis through studies of lunar samples brought back by the Apollo missions, computer simulations, and the similarities between Earth and Moon's isotopic compositions.