The tough-to-spot supernova SN 2011ef in the dim galaxy UGC 12640 photographed on July 22. Credit: William Wiethoff
Sometimes you just can’t trust your eyes. That’s why I’m always careful to examine objects, especially faint ones, multiple times through the telescope until my confidence level rises to the certainty of “Yes, I see it!”
That happened two nights ago when searching for a newly discovered supernova in the faint galaxy UGC 12640 in the constellation Pegasus. Embedded as it was near the galaxy’s center, the star’s light was partly masked by the galaxy’s hazy core, making it very tricky to see. Only after 20 minutes of looking – first with my right eye and then with the left – and employing every technique I knew for squeezing the last photon of light from a faint object was I certain of seeing it.
Other nights, I can persevere even longer, looking for a faint comet or galaxy detail and still not find my quarry. That’s when it’s time to move on to something a little less challenging. It’s so easy to see the thing you really want to see, especially when it’s at the limit of observation. One’s expectations and assumptions can literally make things materialize from the background noise.
That brings me to Mars. Seeing fine details on planets is always challenging. Mars, Jupiter and Saturn look great in photos, but their globes are small and flutter about when viewed through Earth’s tremulous atmosphere. To see beyond the gross features, you need a quality instrument, high magnification and calm air. While it’s theoretically possible to use high magnifications with even small telescopes, the more power you use, the fainter and softer the image. Magnification’s a beautiful thing until you realize you’re also magnifying air turbulence between you and the object. Only on nights when the ‘seeing’ conditions are calm do fine details rise above the noise.
Map of Mars by Giovanni Schiaparelli made in 1888 showing his 'canali'.
Back in the early 20th century, a wealthy Bostonian named Percival Lowell got a bad case of Mars fever after learning of Italian astronomer Giovanni Schiaparelli’s observations of Mars. During its favorable approach to Earth in 1877, Schiaparelli observed a series of linear features on its surface that he dubbed ‘canali’, the Italian word for ‘channels’. A channel is a natural feature as opposed to a ‘canal’ which is a man-made waterway. Schiaparelli imagined them as broad, shallow water courses that extended thousands of miles across the planet’s vast desert-like landscape.
Percival Lowell, circa 1904. Credit: J.E. Purdy
Back in America and elsewhere, his channels were mistranslated into English as ‘canals’. When the reports appeared in the popular press, it led to much speculation about Martian life and the function of the ‘canals’. Percival Lowell was inspired by Schiaparelli’s drawings to build an observatory just outside of Flagstaff, Arizona dedicated to studying the planet Mars. Lowell Observatory, on Mars Hill, is still open today. On public observing nights, you can still look through Percival’s beautiful 24-inch refracting telescope. I stood in line on a lovely evening there a few years back. When it was finally my turn at the eyepiece, I got an most satisfying eyeful of the planet Jupiter.
Lowell’s drawings of Mars and his interpretation of the dark markings went a step beyond those of Schiaparelli’s. In place of curving channels, Lowell saw straight, linear features connecting continents and ‘oases’ on Mars. In his mind, their precise, geometrical shapes clearly indicated they’d been built by intelligent beings. Furthermore, Lowell hypothesized that a dying race of Martians created the network of canals to carry water from the poles to the parched equatorial regions to water crops. Their planet was drying up and the canals were an effort to deal with what we would call global climate change.
Mars and its canals as seen and drawn by Percival Lowell
It’s no surprise canals were on everyone’s mind in the late 19th century. The Suez Canal connecting the Mediterranean Sea and Red Sea opened in 1869, and the Panama had long been on the drawing board. It opened in 1914.
The public loved Lowell’s ideas. He wrote a book about his observations in 1895 called “Mars” as well as articles for Popular Astronomy and Atlantic Monthly and lectured widely. Thanks to strong convictions and an intense presence, Lowell gained a large following. More books followed — “Mars and Its Canals” in 1906 and “Mars as he Abode of Life” in 1908. He was on a hot streak.
Percival Lowell observing through the 24-inch refracting telescope at Lowell Observatory
Astronomers however were skeptical. Only a few saw Lowell’s canals. Most, like the famous American astronomer E.E. Barnard, spied lots of things that Lowell missed but never discerned a single linear feature. Even observers using the 100-inch Hooker telescope on Mt. Wilson, then the largest in the world, failed to see them. Lowell countered that larger scopes were more plagued by atmospheric turbulence than his. Astronomer William Campbell used a new spectroscope to search for water vapor in Mars’ atmosphere during its close approach to Earth in 1894 and found none. Over time, it became obvious that the canals were illusions caused by an active imagination grasping at faint and tenuous details visible at the telescope’s resolution limit.
To rescue his reputation, Lowell worked on other projects including irregularities in the orbit of Uranus that led him to predict a ninth planet beyond Neptune. He called it Planet X. Although his idea later proved wrong, he inspired the search that led ultimately to the discovery of Pluto at Lowell Observatory by Clyde Tombaugh in 1930.
Lowell's and Schiaparelli's channels/canals and ideas about Mars helped inspire H.G. Wells' 1898 book "War of the Worlds" about an invasion from Mars.
Lowell’s fascination with Mars and possible Martian life lived on. The thread was not only picked up by science fiction writers but many amateur and some professional astronomers, who continued to look for evidence of some ‘low’ form of plant or microbial life on the Red Planet. I still recall drawings of the canals in the astronomy books I perused as a kid. Until the Mariner 4 probe returned photos of a barren, crater-ridden Mars in 1964, many of us still secretly hoped Mars had life. We’d screw up our eyes at the telescope eyepiece hoping to see the planet’s dark markings turn a pale green during Martian spring and summer.
It still seemed possible, even as late as the early 1960s, that water from melting polar ice soaked the dry land beyond, perhaps stimulating the growth of Martian versions of moss and lichens.
No evidence of artificial canals or any other alien structures are known on Mars today, however you’ll find plenty of evidence of past water in the form of dry stream beds and enormous outflow channels. Perhaps there was even time for life to fire up and evolve. The two Viking landers, Phoenix lander, three rovers and numerous orbiters are a start, but we’ve really only scraped the surface of the Red Planet. There’s a whole world of discovery out there, and the possibility of Martian life lingers in the air in every discussion about Mars, much as it must have during Lowell’s time.
Streamlined islands formed where long-ago water flowing on the surface of Mars encountered obstacles along its path. Here water was diverted by two 5-6-mile-diameter craters lying near the mouth of Ares Vallis. Credit: NASA
In light of all the unsubstantiated ideas flying around the Internet about Comet Elenin, wayward stars, 2012 and the like, there’s a lesson we can all learn from Lowell’s foibles: Maintain a healthy skepticism and avoid leaping to fantastic conclusions based on scanty data and wishful thinking.