The Wonder of Seeing Red
SAN FRANCISCO — In 1956, Mars came within 35 million miles of Earth. Its unusual proximity created an international stir of excitement that prompted many budding young observers, myself among them, to get telescopes and have a look for themselves. Twelve years old at the time, I badgered my parents into buying me a little telescope as an early Christmas present in order to view that October’s event. Few could see anything much through my wobbly spyglass, but by taking it into our frontyard in Key Biscayne, Fla., and training it on Mars night after night, I became enchanted with the Red Planet and with the night sky in general, and I’ve been stargazing ever since. When I interviewed dozens of accomplished amateur astronomers in the course of researching a book, many reported that they too had gotten started during the 1956 opposition.
Mars was mighty mysterious back then. No spacecraft had been there, and all that was known about it had been garnered by observers peering through telescopes and taking blurry photographs. The intricate network of “canals” that the wealthy amateur Percival Lowell charted from his private observatory in Flagstaff, Ariz., was widely -- and rightly -- dismissed as an optical illusion, but nobody could yet be certain that Lowell’s notion of a parched Martian civilization having built canals to ferry water from the poles might not be correct.
We kids figured that astronauts would soon explore Mars and determine firsthand whether there was life of any sort there, much less intelligent canal builders. We read books, written by the rocket scientists Wernher von Braun and Willy Ley and illustrated by the space artist Chesley Bonestell, that detailed how we Americans would soon construct a gigantic, wheel-shaped space station in Earth orbit and use it as a base from which to establish colonies on the moon and then Mars. We assumed that people would be living on the Red Planet by the time the great opposition of 2003 rolled around, rendering terrestrial observations superfluous.
But that didn’t happen.
Now, Mars is nearing Earth again. Rising in the eastern skies these August evenings, a garnet beacon brightens each night as the Red Planet draws ever closer. On Tuesday night, it will pass within 34.6 million miles of us -- its closest approach in 60,000 years. This encounter extends into September, affording professional astronomers and amateur stargazers alike a unique opportunity to get a firsthand look at an alluring and still-mysterious world.
To see much of anything on Mars you’ll need a telescope, but that doesn’t necessarily mean running out and buying one. Using a telescope is like playing a musical instrument: It takes practice to get good at it, and beginners risk buying one that’s too cheap to work well, or one so expensive that it prompts pangs of regret if it winds up gathering dust in the hall closet. You may be better off trying somebody else’s telescope instead, by taking part in a public night at the local science center or dropping in on a “star party” being thrown by local amateur astronomers.
When you do get a look at Mars through a telescope, take your time. Observing is an active process, like cross-examining a witness in court, not a passive one like watching TV, and the longer and more attentively you look, the more you’ll see. At a typical magnifying power of around 75x, Mars in a telescope looks about the same size as the full moon does to the unaided eye. On its ocher disk you should be able to see red deserts, some of the more prominent “continents” -- rocky plateaus elevated above the deserts -- and, most conspicuously, the gleaming white south polar ice cap, which is currently tilted toward Earth and is melting along its fringes as Mars goes from southern-hemisphere spring into summer.
Interference from Earth’s atmosphere makes the Martian disk appear to shimmer and quake. By waiting for moments when the air settles down and the view steadies, you may be able to perceive intricate detail on the continents, discern the icy fingers where the polar cap edges into the deserts, and view the white clouds that sometimes form above Olympus Mons, the largest volcano in the solar system, and other towering Martian mountains.
The ideal times for observing Mars are when it “transits,” reaching its highest point in the sky. Currently this happens around 1:30 a.m., but by mid-September transit times will have edged into the pre-midnight hours. The Martian disk will be shrinking by then but should still be well worth seeing -- unless a global dust storm kicks up and obscures the surface features. Such storms, which have marred some prior encounters, “turn exuberant observers into sad complainers,” writes Michael Bakich of Astronomy magazine. As with the adage about voting in Illinois’ Cook County, the preferred way to observe Mars is early and often. By viewing Mars on several nights, you can benefit from your own growing experience and see more of the Red Planet. (A Martian day, called a “sol,” lasts 37 minutes longer than an Earth day, so only part of Mars can be viewed on any given evening.)
Close encounters with Mars are called oppositions because they occur when Mars stands opposite the sun in the sky. They reoccur every 780 days or so, when Earth, clipping along on its inside-track orbit, draws abreast of slower-moving Mars in its larger orbit. But all oppositions are not created equal. Mars’ orbit is much more elliptical than Earth’s, so that the distance from Mars to the sun varies from 128 million to 155 million miles. Superb oppositions like this year’s transpire when Mars happens to draw closest to the sun at the same time that Earth is simultaneously passing by.
We know more about Mars now than we did during the opposition of 1956. Starting in the 1960s, robotic probes were dispatched to the Red Planet, culminating in the mighty Viking missions of the 1970s -- which put two orbiters around it and two landers on its surface -- and continuing with recent expeditions by the Pathfinder and Mars Global Surveyor missions. But no humans followed them.
Historians and sociologists continue to debate how and why the manned space program got stuck in low Earth orbit. Whatever the reasons may be -- lack of money, perhaps, or national will, or politicians’ vision -- they weren’t technological. The mighty Saturn V rocket that propelled Apollo astronauts to the moon would have sufficed to assemble an interplanetary spaceship in orbit and dispatch a crew to Mars. Instead, the Apollo project’s leftover Saturns were scrapped, and the space agency switched to reliance on the space shuttle.
As a result, Mars remains a planet of mysterious allure. Thousands of photographs and other data indicate that water once flowed on its surface, suggesting that at some point it was a warmer planet with a denser atmosphere. (Nowadays, conditions on the Martian surface are as cold, and the air as thin, as on the wings of a highflying jet, and water can exist there only as ice or vapor, not liquid.) We don’t know where the water has gone -- frozen in the soil, most likely -- or whether it once supported life, or still does today.
Most disturbingly, we don’t know what went wrong. As residents of its nearest neighboring planet, we humans would like to learn how Mars evolved, what has saved us from a similar fate and how we can avoid heading in the same baleful direction. The best reason to study Mars is, in the end, to understand the literal life-and-death matter of how planets work.
Amateur astronomers play an important role in this effort. Hundreds are scrutinizing Mars around the clock these nights, charting the course of Martian weather and keeping an eye on dust storms that threaten to obscure the surface during oppositions. Many use digital cameras to take images of Mars with backyard telescopes that can rival those made by professionals using mountaintop observatories. And, because the amateurs have time and equipment on their side, their monitoring is in some ways more extensive than the professionals can always muster.
Still, one wonders how long we earthlings are destined to remain mere observers, rather than explorers, of Mars. I once asked the veteran astronaut Kathryn Sullivan how long she would be willing to stay on Mars if she had a chance to go.
“How long will you let me stay?” she replied, her face lighted up with the keen anticipation of a wolf eyeing a steak. “Put me on Tharsis” -- the domed desert from which protrudes Olympus Mons -- “for a year, and I’ll give you the keys to the planet.” Whether future astronauts will get that chance may be the biggest Martian mystery of them all.
