For the next two weeks, Mars hovers at its closest to us. It’s sort of a big deal. While Venus can come closer, and Jupiter’s more intriguing, Mars is the most Earthlike world within light-years of Saugerties.
Normally it’s a dim object that attracts no more attention than a salami sandwich. But every 26 months, faster-moving Earth, gliding around the Sun at 18 miles per second compared to Mars’ slower 15 miles per second, catches up to it. This is happening right now, letting the “Red Planet” blaze only slightly less brilliantly than Sirius, the brightest true star.
This opposition on Tuesday night, April 8, is when Mars stands opposite the Sun in our sky, thus rising at sunset and getting highest in the middle of the night. Mars sits in the constellation Virgo, just above Virgo’s main star Spica, whose distinct blue dazzle creates an obvious and splendid color contrast: orange and blue, just like a Howard Johnson’s.
Finding it? A no-brainer. Just step out anytime after 9 p.m. and look east. Make it 10 p.m. if you’ve got hills or obstructions. You’ll see Mars floating above Spica. They shift into the south a few hours later.
Things are going to get truly spectacular during next Monday night’s total lunar eclipse, on the 14th. The orange planet and blue Spica will hover near the suddenly copper-red eclipsed Moon. More about that next week: a truly don’t-miss event.
Now for the “full disclosure.” Usually when Mars comes to opposition and is closest to Earth, it vastly outshines Sirius. It even outshone Jupiter during the historic Martian close approach 11 years ago. Its current “best” is merely bright, not dazzling, which reveals that this is not a very close visit.
Mars’s orbit is oval, lopsided. Every 26 months when Earth and Mars meet, the encounter can occur at either a narrow gap between our orbits, as it did in late August 2003, or the widest possible gap, which happened last opposition, in late winter of 2012. This time it’s nearly at its worst, which makes it appear very small through backyard telescopes: a mere 15 arcseconds.
It is now early summer on Mars, and its northern polar cap has largely melted. So its most striking telescopic feature, its snow-white cap, will be small, although dark, blotchy surface features may still be evident. If you do have a telescope, choose a night when stars are not twinkling, which denotes steady air. On a normal twinkling night, the tiny Martian disk will be a blurry, unimpressive mess.
Ancient peoples regarded Mars as a god circling the Earth. Its ruddy color suggested blood or fire, and thus came its association with war, leaving us a legacy of terms like “martial arts” and “court martial.” It took until the modern era of computer power and statistical analysis to lay to rest all warlike connections. For example, wars have historically broken out no more often when Mars was close to us than at other times.
As for its odd corkscrew trajectory among the stars, tremendous brightness changes and periods of reversed motion – all of which drove the ancients bonkers – these are simple consequence of us catching up to that small planet and passing it in space. That’s why Mars is now temporarily chugging westward against the stars of Virgo – the ‘wrong way,’ the opposite of how it actually travels through space. It’s like passing a slow truck on the highway. It seems to move backward, even though it’s not.
Mars will remain an impressively brilliant “star” only during April. It will lose half its light during May. As they say on TV, act now: This offer will expire.
Want to know more? To read Bob Berman’s previous “Night Sky” columns, visit our Almanac Weekly website at www.HudsonValleyAlmanacWeekly.com.