Why is Mars so close?
Mars is going through what astronomers call a “perihelic opposition.” This involves both the shape of Mars’s orbit and the relative positions of Mars, Earth, and the Sun. Opposition occurs when Mars is more or less directly opposite the Sun as seen from Earth. This happens about once every two years. Both Earth and Mars are orbiting the Sun, but Earth has the “inside lane,” so we “lap” Mars every 25.5 months. Each time we pass by Mars, Mars goes through an opposition. It is at these times that Mars is fairly close to Earth. Generally somewhere between 34.6 and 63 million miles separates them at each opposition. The separation between Mars and Earth at opposition is not always the same because Mars’s orbit is not exactly circular. It is elliptical or oval, as are all planetary orbits, and the Sun is not exactly in the center. The point in Mars’s orbit where it is closest to the Sun is called the perihelion, (peri for close, as in periscope, and helion from helios, Greek for the sun). Th
