Executive Orders are controversial because they allow the President to make major decisions, even law, without the consent of Congress. This, of course, runs against the general logic of the Constitution -- that no one should have power to act unilaterally.
Voyager 1 has since become the fastest and most distant man-made object in the Universe, travelling at around 61,500km/h at a distance of 17.6 billion km from the Earth. Perhaps most incredible of all, NASA is still in communication with it, despite radio signals taking 16 hours to reach it. Image Â© NASA.
Voyager 1, which is zipping along at 38,000 mph (61,000 km/h), is currently 11.7 billion miles (18.8 billion kilometers) from Earth. Voyager 2 took a different route through the solar system and is now 9.5 billion miles (15.3 billion km) from home. Voyager 2 may join its twin in interstellar space three or four years from now, Stone said, stressing that it's tough to predict a departure date in advance. Follow Mike Wall on Twitter @michaeldwall and Google+.