The Grand Canyon in Arizona is one of Earth's natural wonders, carved out over millions of years by the gradual erosion power ...

They were dug out by debris sent violently aloft when an asteroid or comet struck the lunar surface 3.8 billion years ago.

This impact unleashed about 130 times the energy of the current global inventory of nuclear weapons. Read more at ...

An undated artistic rendering shows an asteroid or comet striking near the Moon's south pole about ... following a change in the orbits of the solar system's giant planets - Jupiter, Saturn, Uranus ...

"When the impacting asteroid or comet hit the lunar surface ... The canyons are straight-line scars on the lunar surface, extending outward from a large and round impact crater, with smaller ...