When are Mars and Earth the closest?

Answer 1

Six to seven months for current space probes (2011-2012).

Because Earth and Mars have separate and unrelated orbits, the actual closest approach (about 58 million kilometers) only occurs once every few decades. But each year, the Earth comes within 60 to 100 million kilometers of Mars. With current technology (2012), space probes take around 7 months to make the journey to Mars, and usually longer. Any manned mission would probably need to reduce this time well below 6 months each way.

Answer 2

Much has been made of the fact that the August 27th encounter with Mars is the closest in some 60,000 years. Neanderthals were the last to observe Mars so favorably placed. This is true. It's also a bit of hype. Mars and Earth have been almost this close many times in recent history.

Some examples: Aug. 23, 1924; Aug. 18, 1845; Aug. 13, 1766. In each case Mars and Earth were approximately 56 million km apart.

Answer 3

Mars and Earth are closest to each other during opposition, which occurs about every 26 months. During this time, the two planets are at their shortest distance from each other in their respective orbits around the Sun.

Answer 4

About 55 million km.
56,000,000 kilometers.