At its biggest for the next 15 years, it’s still much smaller than the Moon.
On October 6, 2020, Mars makes its closest approach to Earth until 2035.
Earth and Mars both orbit the Sun in the same direction, but at different speeds and distances.
Consequently, Earth only overtakes Mars once every 780 days: just over 2 years.
These close approaches create optimal launch windows, minimizing the fuel required to reach Mars.
From Earth’s perspective, Mars’s angular size varies the most, percentagewise, of any planet.
Telescopes reveal Mars’s axial rotation, even during a single night.
Unlike Earth, Mars’s seasons are determined by its highly elliptical orbit, not its axial tilt.
Martian “winter” occurs when it’s farthest from the Sun, with “summer” arriving when it’s closest.
When Martian summer aligns with Earth’s closest approach, Mars appears at its largest.
Martian summer coincides with the highest dust storm risks, which famously occurred in 2001 and 2018.
This year, Earth overtakes Mars near Mars’s perihelion, creating its closest approach until 2035.
Mars’s presently cooperative weather enables even amateur skywatchers to see surface features, like its (shrunken) polar ice cap.
Mars remains bright and celestially well-positioned for viewing all throughout October.
Even at a maximum of 25.1 arc-seconds in size, Mars only ever appears point-like without additional magnification.
Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words. Talk less; smile more.
Starts With A Bang is written by Ethan Siegel, Ph.D., author of Beyond The Galaxy, and Treknology: The Science of Star Trek from Tricorders to Warp Drive.