From NASA
Last night Mars was on the exact opposite side of the Earth from the Sun. Mars is especially photogenic at this time because it is fully illuminated by the sun as viewed from Earth.
About every two years Earth's orbit catches up to Mars' orbit, aligning the sun, Earth, and Mars in a straight line, so that Mars and the sun are on "opposing" sides of Earth. This phenomenon is a result of the difference in orbital periods between the orbits. While Earth takes the familiar 365 days to travel once around the sun, Mars takes 687 Earth days to make its trip around our star. As a result, Earth makes almost two full orbits in the time it takes Mars to make just one, resulting in the occurrence of Martian oppositions about every 26 months.
Mars will be visible at night all week and can be easily seen without a telescope or binoculars.
Look to the southeast just after twilight. Mars should be visible all night long
Mars has been even closer to Earth before. In August 2003, they were just 35 million miles (56 million km) apart, a quirk stemming from the planets’ slightly oval-shaped orbits around the sun.
It will be almost 300 years before the planets come that close again.
Use this link to learn more.
