Mars is the world orbiting the sun one step outward from Earth’s orbit. Earth takes one year to orbit the sun once. Mars takes about two years to orbit once. The adjacent orbits of Earth and Mars are the reason Mars is one of the most fascinating planets to watch in our sky, and they’re the reason Mars is sometimes bright and sometimes faint. Mars is brightening dramatically now … and is going to get much brighter in the coming weeks!
The image above shows Mars in late March, 2016. Right now, Mars is traveling only slightly ahead of Earth in the race of the planets around the sun.
April 8, 2014, is the date Earth last went between the sun and Mars.
We’ll pass between the sun and Mars again on May 22, 2016, and – from now until around that time – you watch watch as Mars grows steadily brighter and shifts into easier view in our evening sky.
The image below – which shows the relative positions of Earth and Mars on May 22, 2016 – shows why.
The brightness of Mars in our sky depends on where our two planets are in orbit around the sun. Sometimes Earth is close to Mars, and sometimes we are far away.
We are relatively close – and Mars appears at its brightest in our sky for that two-year period – every time Earth passes between the sun and Mars. At this time, Mars appears at opposition – opposite the sun in our sky – rising in the east when the sun sets in the west.
Oppositions of Mars recur about every two years and 50 days.
So Mars alternates in appearing bright and faint in our sky. It’s bright in the years we pass between it and the sun. It’s faint in the years in between, when Mars lies far across the solar system from Earth – at times hidden from our view by the sun itself.
Mars will be particularly close at the 2016 opposition because of another cycle … which makes some oppositions of Mars closer than others. To learn more, check out a chart specially provided by the Royal Astronomical Society of Canada: Mars oppositions 2010-2022.
If you do look at the link above, you’ll see why Mars comes particularly close in May 2016 and will do so again in July 2018.
So some oppositions of Mars are closer than others. But, in general, Mars will be close and bright in our sky every two years for billions of years to come!
Mars is already lovely to behold, and, in 2016, it’s near another planet on the sky’s dome, the planet Saturn. Mars and Saturn will be near the moon around the end of April, 2016. Identify them then, and enjoy them for months to come!
See the chart below.
Also see a video of Mars and Saturn in 2016.
Bottom line: Mars is bright when it and Earth are on the same side of the sun. It’s faint when it and Earth are on opposite sides of the sun. 2016 is a grand year for seeing Mars. The best months for Mars viewing in 2016 are May and June. But the planet remains bright throughout the summer of 2016. Watch for it!