The moon blocked sun in a total solar eclipse this morning, briefly turning dawn back into night over parts of northern Australia and the southern Pacific Ocean.
The ever-rare total solar eclipse began just after sunrise in northern Australia, thrilling nearly 50,000 spectators who had flocked to the city of Cairns to witness it:
It was the first total solar eclipse in Australia in a more than a decade and the last eclipse of its kind that humans will see anywhere on Earth until 2015.
Solar eclipses occur when the moon lines up with the sun in the sky, its shadow blocking the sun's rays and light from a viewer's perspective on Earth.
Because both Earth and its moon are in motion, these celestial events are fleeting. Totality, when the sun is completely obstructed, lasts but a few minutes.
There are three main categories: total, partial and annular eclipses (in which the outer edge of the sun shines like a ring around the moon in the sky).