This week alone, the Russian president unveiled two nuclear-capable weapons - but their value may be more symbolic than military.

The U.S. has not conducted a nuclear test in over 30 years. Experts say doing one now could make America less safe.

If an asteroid is on a collision course with the moon, what should humanity do? Try to nudge the space rock out of the way before it strikes? Obliterate it with a nuclear explosion? Such a cosmic ...