Left behind on the moon were the footprints of Armstrong and Aldrin, an American flag and scientific equipment.

VOA: special.2009.07.15

Scientific American magazine says huge lasers turn only about twenty to thirty percent of the energy they use into a laser beam.

VOA: special.2010.09.01

The study appeared in the official scientific journal of the American Academy of Physical Medicine.

VOA: special.2010.02.03

Dr.Brook, who chaired group that produced a scientific statement on air pollution and cardiovascular disease for the American Heart Association.

VOA: standard.2010.08.04