For the first time, scientists have observed DNA being damaged by ultraviolet (UV) light.
Ohio State University chemists and their colleagues in Germany used a special technique to watch strands of DNA in the laboratory sustain damage in real time.
They observed the most common chemical reaction among a family of reactions on the DNA molecule that are linked to sunburn, and discovered that this key reaction happens with astounding speed -- in less than one picosecond, or one millionth of one millionth of a second.
An undamaged stack of thymine bases is colored green in the DNA double helix on the left.