MARS CLOSE APPROACHES
Mars Close Approaches
In 2018, Mars will appear brightest from July 27 to July 30. Its closest approach to Earth is July 31. That is the point in Mars' orbit when it comes closest to Earth. Mars will be at a distance of 35.8 million miles (57.6 million kilometers).
Mars Close Approach
What is Mars Close Approach?
Close Approach is when Mars and Earth come nearest to each other in their orbits around the sun. Close is a relative term. The minimum distance from the Earth to Mars is about 33.9 million miles (54.6 million kilometers). However, that doesn't happen very often.
Orbits of Earth and Mars at Close Approach
Illustration of the orbits of Mars and Earth around the sun during Close Approach. Credit: NASA/JPL-Caltech
If Earth and Mars had perfectly circular orbits, their minimum distance would always be the same. However, they have elliptical (egg-shaped) paths.
In addition, gravitational tugging by planets constantly changes the shape of their orbits a little bit. Giant Jupiter especially influences the orbit of Mars.
The orbits of Mars and Earth are also slightly tilted with respect to each other.
All of these factors mean that not all close encounters are equal. In 2003, Mars made its closest approach to Earth in nearly 60,000 years! It won't be that close again until the year 2287.
When Mars and Earth are close to each other, Mars appears very bright in our sky. It also makes it easier to see with telescopes or the naked eye. The Red Planet comes close enough for exceptional viewing only once or twice every 15 or 17 years.
However, don't be fooled by the Mars Hoax! Since 2003, this urban legend gets circulated through email and social media every time Mars makes a Close Approach.
The message is that Mars will look as big as the Moon in our night sky. If that were true, we'd be in big trouble given the gravitational pulls on Earth, Mars, and our Moon!
When does Mars Close Approach Occur?
Since Mars and Earth are at their closest, it's generally the best time to go to Mars. Many Mars missions have taken advantage of the close distance to visit the red planet. That's why, depending on budgets, you'll often see that Mars missions launch about every two years:
Next Mars Close Approach is in 2020
An artist's view of the size of Mars during Close Approach in 2018 and 2020.
Missed seeing Mars Close Approach in 2018? Not to worry! The next Mars Close Approach is Oct. 6, 2020, when the Red Planet will be only 38.6 million miles (62.07 million kilometers) from Earth.