Strontium atoms floating in the center of this photo are the heart of the world's most precise clock. The clock is so exact that it can detect tiny shifts in the flow of time itself.
Courtesy of the Ye group and Brad Baxley/JILA
Physics is full of big, interesting questions about phenomenon such as black holes. This illustration shows the supermassive black hole at the heart of the active galaxy NGC 3783 in the southern constellation of Centaurus.
We think that life came from non-life, from the increasing complexity of chemical reactions between biomolecules present on the primordial Earth. But what about the universe? How did it come to be if there was nothing before?