The sun and moon aligned over the earth in a rare astronomical event on Sunday - an annular eclipse that dimmed the skies over parts of China, briefly turning the sun into a blazing ring of fire.
The last solar eclipse with the shape of ring occured in China on January 15, 2010. The next one is not to occur until 2020. That is because the phenomenon requires a particular set of orbital dynamics.
An annular eclipse occurs when the moon's orbit is at its furthest point from the Earth and closer to the much larger sun. That juxtaposition allows the moon to block more than 90 percent of the sun's rays when the two orbs slide into alignment.