The chart below shows the dates of eclipses in the years 2006 and 2007. What is the best explanation for the frequency of eclipses? The Moon's orbit is tilted relative to the plane of the Earth's orbit. About every six months, the Sun, Moon and Earth are aligned enough for a solar and a lunar eclipse to occur. The Earth and Moon orbit the Sun in opposite directions. When the Moon's orbit crosses the Earth's orbit, a lunar or solar eclipse will occur. A lunar or a solar eclipse occurs every time the Moon orbits the Earth. The Moon orbits the Earth four times a year. The atmospheric conditions that cause eclipses are only found at certain locations and times of year.