Mars closest to Earth on May 30, 2016

1. Mars closest to Earth on May 30, 2016
http://earthsky.org/
MAY 30, 2016
Image at top from the Hubble Space Telescope on May 12
On May 30, 2016, the red planet Mars comes closer to Earth than it has been since
November 2005. It lies 46.8 million miles (75.3 million km) from Earth on this date.
This is Mars’ closest point for this year. That’s in spite of the fact that Earth passed
between Mars and the sun (the Martian opposition) on May 22.
View larger. In 2016, Mars will appear brightest from May 18-June 3. Its closest approach to Earth
is May 30. That is the point in Mars’ orbit when it comes closest to Earth. Mars will be at a distance
of 46.8 million miles (75.3 million kilometers). Credit: NASA/JPL-Caltech
Why wouldn’t we be closest to Mars on the day we pass between it and the sun?

2. If both the Earth and Mars circled the sun in perfect circles, and on the same exact
plane, the distance between Earth and Mars would always be least on the day of
Mars’ opposition. But we don’t live in such a perfect universe. Planets have elliptical
orbits and a perihelion (closest point) and aphelion (farthest point) from the sun.
Mars orbit around the sun takes 687 days in contrast to 365 days for Earth. It has a
year nearly twice as long as ours. Earth’s closest point to the sun comes yearly, in
January. Mars will be closest to the sun next on October 29, 2016.
Right now, with each moment that passes, Mars is still drawing closer to the sun.
And that is how its distance from us can be less on May 30 than on May 22, when
Earth passed between the sun and Mars.
Generally speaking, Mars is brightest in 2016 from about May 18 to June 3. It is now
shining nearly on par with the planet Jupiter, and it’s not very often that Mars can
match Jupiter in brilliance!
Tonight’s close encounter between the Earth and Mars will be the closest until
around the time of the martian opposition on July 27, 2018.
Artist’s illustration of the orbits of Earth and Mars, via NASA.

3. Artist’s illustration of the relative tilts of the orbits of Earth and Mars, via NASA.
Although its exact closest point in 2016 is May 30, in contrast to May 22 for
opposition, Mars always comes closest to Earth at the vicinity of opposition. The time
interval between a Mars’ opposition and its least distance from Earth can be as long
as 8.5 days (1969), or as little as 10 minutes (2208 and 2232).
Earth orbits closer to the sun than Mars does, and we move in orbit more swiftly than
Mars. Our world gains a lap on Mars on average about every 780 Earth days, or
slightly over every two years.
Mars at opposition in 2016, in comparison to 2018, as viewed through a telescope. Illustration
via nasa.tumblr.com.

4. The cycle of Mars’ very best appearances in our sky recurs every 15 to 17 years.
Mars will have one of those amazing years in 2018, when Mars comes to within
0.38496 astronomical units of Earth on July 31, 2018. (One astronomical unit =
Earth/sun distance.) The last amazing year occurred in 2003, when Mars was only
0.37272 astronomical units from Earth on August 27, 2003.
Earth swings between Mars and the sun every other year, although at progressively
later dates. Earth will next lap Mars on July 27, 2018. Its closest approach to Earth
that year will be July 31. After that, Earth will next lap Mars on October 13, 2020.
Mars makes a prominent triangle with 2 other objects – the planet Saturn and star Antares in
Scorpius – in 2016. Watch for them in the east each evening, south at your local midnight (or north
if you are in the S. Hemisphere) and in the west before dawn.
Mars is out almost all night long now. It looks like a bright reddish star, shining with
a steadier light than the twinkling stars. Look for Mars in the eastern sky at nightfall
– highest in the sky near midnight – and in the west as morning dawn starts to light
the sky.
Bottom line: Mars opposition – when Earth flew between the sun and Mars – was
May 22, 2016. But the distance between Mars and Earth is least on May 30, 2016.