Science News and Headlines

How Often Does Earth Transit the Sun for an Observer on Mars?

From the perspective of Mars, Earth transits the Sun only four times within a 284‑year cycle, occurring in May or November with intervals of 100.5, 79, 25.5 and 79 years. The most recent transit was on May 11, 1984, and the next will be on November 10, 2084. During a transit Earth and its Moon appear as tiny black dots crossing the solar disk, requiring a filtered telescope to observe safely. These events coincide with Mars being at opposition, making the planet brightest from Earth at the same time.