WASHINGTON – Astronomers say a small asteroid is about to make a fiery but harmless dive into Earth's atmosphere early Tuesday morning over Africa.

Harvard scientists announced late Monday afternoon that the unnamed asteroid will burn up in the sky, making a fireball that people in northern Africa should be able to see. The rock is between 3 feet and 15 feet in diameter. It's expected to enter Earth's atmosphere above Sudan at 10:46 p.m. EDT Monday, which is just before dawn in Africa

Harvard astronomer Tim Spahr said the asteroid is so small it can't reach the ground and will not hurt anyone. Astronomers have tracked the sky for years looking for potential comets and asteroids that regularly pelt Earth, but this is the first one they saw coming.