Mars 2018: Dust Storm Aftermath

August 2018  :  Dave Huestis

Amateur astronomers have been anxiously awaiting the closest approach of Mars to the Earth since 2003. On July 31 the Earth-Mars distance will be only 35,785,537 miles. These two planetary neighbors won’t be this close again until 2035, so I’m sure the news media will be hyping the event. It’s been over two years since I’ve written about Mars. Why? As it is with most things astronomical, events in our solar system occur in a cyclic manner. Earth and Mars have a close encounter every 26 months. During the last few months the Earth has been catching up to Mars in our respective orbits, since the Earth orbits the Sun (one year) in less time than Mars does (1.88 years). So the Earth effectively laps Mars. Unfortunately not all Mars’ close encounters are favorable ones. That fact is due to the eccentricity of Mars’ elliptical orbit and its distance from the Sun. However, this year’s close encounter was going to be splendid! A big deal. I was calling it Mars Mania.

I spent several weeks preparing a special Mars observing guide for my August column, as even a small backyard telescope would reveal surface markings, including the South Polar Ice Cap. The original version of this article was written in May 2018. (You can find that first version up on the Skyscrapers web site: http://www.theskyscrapers.org/mars-mania-2018-before-the-dust-storm.) The local observatories had also been planning special observing sessions to provide the general public wonderful views of this desolate world. 

Unfortunately a major dust storm began on Mars on May 30 that encircled the planet within three weeks and enshrouded it, preventing surface details from being observed. Even NASA’s Opportunity Rover had to shut down because day turned into night and its solar panels couldn't generate enough electricity to operate.

This circumstance has to do with the Martian seasons. Dust storms are more prevalent in Mars’ southern hemisphere (now tilted towards us), and begin in Martian southern hemisphere spring (now) through summer (which begins October 16). This scenario also coincides in 2018 with Mars at perihelion (closest to the Sun), which is on September 16. So for 2018 the conditions were favorable for dust storm development.

Unfortunately this dust storm shows no signs of abating, and even if it did so soon, once dust is lifted up into the thin Martian atmosphere it takes a long time for these particles to settle out. The splendid views of the Martian surface we have been anticipating since the last closest approach in 2003 are now compromised.

So Mars Mania has become a Mars Bust! 

The following Mars observing guide is even briefer than originally intended, as there are just so many ways one can describe the featureless peach-colored “beach ball” that is now Mars.

I am not going to recount the history of Mars’ observations or spacecraft explorations other than to say the initial accounts of possible “canals” on Mars at the end of the 19^th century captured our imagination and most assuredly hastened our spacecraft exploration of this desolate world. If you would like some historical background, visit this link on the Skyscrapers web site: http://www.theskyscrapers.org/mars-past-present-and-future.

You can begin to observe Mars as soon as you read this article. Due to a variety of publication dates, you may have missed the close approach (July 31). It won’t matter though, especially since the dust storm has obscured the planet’s surface. Be sure to check out the free public observing sessions at the local observatories. Plans were still being planned for special Mars observing programs.

Mars will not be hard to locate in the sky. In fact, because of the greater amount of dust in its atmosphere, Mars is now slightly brighter than expected as the suspended dust is reflecting more sunlight. On the night of closest approach Mars will rise above the southeast horizon after sunset. You can’t miss its distinct bright pumpkin-orange color. You should wait for it to climb higher into the sky and out of any horizon haze and turbulence. By 10:00 pm Mars will be almost 14 degrees above the horizon and awaiting your scrutiny among the stars of the constellation Capricornus. Later in August it moves into neighboring constellation Sagittarius for a couple of weeks before moving back across the border into Capricornus once again.

You can still focus in on Mars with a telescope. Closer inspection will reveal the surface color to be more peach-like. However, due to the obscuring dust perhaps only a glimpse of Mars’ South Polar Cap will be detectable. It is a fairly bright white feature that is currently tilted 11 degrees towards the Earth. I find it ironic that it’s usually our weather that foils our observing plans for an astronomical event!

It’s certainly a big disappointment that a Martian dust storm of global proportions had to occur now. It will be 17 years until Mars is this close to the Earth again.

Despite the lack of any surface markings to observe, I still encourage you to bring out those telescopes from the basement, attic or garage and treat yourself and your children to Mars. One day they or your grandchildren may set foot upon this exciting landscape. Take a knowledgeable glimpse of an alien world that inspired generations of astronomers and science fiction writers alike to ponder the existence of Martian life-forms.

If you do not own a telescope you should make every effort to visit the observatories throughout Rhode Island to explore the planets close-up. We can only hope Mars’ dust shroud “thins out” over the next few months so we may catch a glimpse of some surface features. Regardless, Jupiter and Saturn will continue to reveal their beauty for months to come. Seagrave Memorial Observatory in North Scituate (http://www.theskyscrapers.org) is open every clear Saturday night for observing. Ladd Observatory (http://www.brown.edu/Departments/Physics/Ladd/) in Providence is scheduled to reopen Tuesday, July 10, and every clear Tuesday thereafter. The Margaret M. Jacoby Observatory at the CCRI Knight Campus in Warwick (http://www.ccri.edu/physics/observatory.htm) is open every clear Thursday night. Also consider visiting Frosty Drew Observatory (http://www.frostydrew.org/) in Charlestown on every clear Friday night. Please visit the respective websites for details. These observing sessions are free and open to the public.

Clear skies.