As Mars moves for an extremely close approach to Earth on Oct. 6, the planet will be a standout in the night sky.
If you look low in the eastern sky on any clear night this week, you'll see a fiery, pumpkin-hued "star" burning brightly shortly after darkness sets. The weeks following Mars' close approach are, considering the "Red Planet" moniker, a great opportunity to understand the true hue of the planet, a yellowish orange, the color of a sandy desert under a high sun.
Mars and its topaz glow shine brighter than any other object in its region of the sky throughout most of October, except, however, on certain nights when the moon is close.
Every extremely close approach of Mars to Earth, of course, would make the planet look extraordinarily radiant and, yes, Mars would comfortably outshine Sirius and even Jupiter, which is normally the second brightest planet, from now until late November.
On Oct. 13, the moment when the sun, Earth, and Mars form a straight line in space, Mars will enter "opposition." When a planet hits opposition, it sits in Earth's atmosphere directly opposite the Sun: it rises at noon, at midnight it reaches its peak point in the sky, and sets at sunrise.
Because Earth and Mars are following elliptical orbits around the Sun, the nearest approach of Mars to Earth normally takes place several days before or after opposition. Using the Multiyear Interactive Computer Almanac (MICA) of the United States Naval Observatory, Mars will arrive at 10:18 a.m. EDT this year on Oct. 6, within 38,568,816 miles of Earth. according to Space.com. It would take 3 minutes and 27 seconds for a light beam to cross the interplanetary gulf between Earth and Mars at this point.
A week later, on Oct. 13, the opposition appears. And it'll be a while before Mars moves any closer to the nearest opposition; it won't happen until Sept. 11, 2035, when the Earth will be 35.4 million miles distant.
However, even after Oct. 13, Mars' eventual fade will begin very slow and steady. Mars will continue to shine through Oct. 17 at a magnitude of-2.6 and will also outshine Jupiter through Oct. 27. Before Nov. 20, the Red Planet will continue to rival Sirius, the brightest star.
Mars' next opposition will come in early December 2022, but as Mars will then be more than 12 million miles farther distant from Earth relative to the intense opposition of this month, it will seem to glow with just half of its present radiance; its disk will seem 24 percent smaller in telescopes than it does now.
Take advantage now because, for another 15 years, Mars won't be this close again.
