In Defense of Percival Lowell

I've spent some time looking at Mars in a telescope and looking at other people's pictures of Mars taken with their telescopes, and I've spent some time looking at Percival Lowell's drawings of Mars from which he derived his famous (or infamous) interpretations about canals and civilizations. I've also been to the Lowell Observatory in Flagstaff, AZ and heard the stories they tell there of his observational acumen.

No one claims there are canals on Mars now, but for some time it has been customary to denounce Lowell's observations as "optical illusions," and to declare that there is "nothing really there" where he said he saw canals. Carl Sagan was among those famous for doing it.

And I never felt it was entirely fair. Lowell was said to have been one of the finest planetary observers of his era, though he lacked academic training in the field. His observatory was located in one of the finest observing locations in the country, and Lowell Observatory is still one of the nation's premiere observatories and research centers.

In an earlier post, I juxtaposed an illustration of Lowell's freehand drawing of what he saw in the Solis Lacus region of Mars in 1896 with three telescopic views taken with a CCD camera in 2006, 110 years later in the UK. The similarities are striking.

There are differences to be sure. Especially the size of the "pupil" of the Solis "eye." Lowell's is small and discreet, the "pupil" in the CCD image is large and extended. But many of the other features correspond almost exactly. Those features we now know include dark-floored craters, "fossae," dark and light terrains, volcanoes, and clouds among other things. I was able to toggle easily between the images, so it was startling to see the correspondences and to spot more of them each time I toggled.

Among the most striking correspondences is the appearance of lines on the CCD images, several of them in remarkably similar positions to those delineated by Lowell.

Side by side comparison; features seen on the CCD image are marked with arrows on the Lowell drawing [Note: South is at the top of the images.]

Side by side comparison of Mars Solis Lacus quadrant
left drawing by Percival Lowell, c. 1896
  CCD telescopic image by D. Peach, 2005
Correspondences noted on Lowell drawing

If you are able to relax your eyes a bit, you will see many -- many! -- linear markings on the CCD image, both light-toned and dark, some of which correspond to Lowell's markings, some of which don't. The correspondence of spots between the drawing and the CCD image taken more than 100 years later is remarkable, especially given the differences inherent in the, telescopes, the techniques and the tendency of the eye and hand to diverge when attempting to record visual impressions. (Think of courtroom drawings.)

The faint linear markings on the CCD image are NOT "optical illusions." They are on all the CCD images from that sequence so they are real in the sense that the CCD camera was able to record them. But there are many other CCD images taken by others around the same time that do not show linear markings as this one does.

What gives?

The "optical illusion" argument tends to fail when CCD images show linear markings similar to those Lowell recorded 100 years before. So other arguments have been put forth proposing that the linear markings are actually a telescopic artifact. Something in the optics of the telescope makes them "appear." This argument was offered in part because other astronomers also reported seeing linear marking corresponding to Lowell's canals, and Lowell for his part reported linear markings on the surface of Venus and Mercury when he trained the telescope on them.

I'm more inclined to accept the optics argument than I am the illusion argument, but even so, it seems to me there's something about the surface of Mars itself that allows and requires the appearance of linear markings in some telescopes but not in others. Given the fact that Lowell's telescope was a huge 24" refractor, and most of the modern amateur CCD images are made through a much smaller reflector or Schmidt/Maksutov Cassegrain telescopes, the "optics" argument becomes difficult to fathom.

[Note (as of 9:30pm Friday, August 10, 2012): a huge limb just broke off a eucalyptus tree down the street, blocking the road, exploding street lamps and power transformers, and causing much to do in the neighborhood. Power went out briefly, but there are wires crossed all over, and the exploded transformer is a big problem. Will probably lose power again as repairs are made. That tree has been there since God was a boy, and it periodically drops fair sized limbs, but this time the branch that snapped was enormous. Good thing nobody (that we know of) was under it at the time. Another big tree on the same property fell a few years ago in a storm, destroying the garage and badly damaging a neighbor's house. A neighbor said he witnessed the whole thing tonight, and he thought it was the end of the world...]

The point I'm making is that Lowell was a very accurate observer who honestly recorded what he saw when he observed Mars. Many of his contemporaries saw similar features. And similar features can still be seen and recorded on the surface of Mars with much different telescopes. I have seen some of them myself. It has never looked to me like the surface is crisscrossed with canals, but it is quite possible to resolve straight lines -- both dark and light colored -- that appear to connect various dark and light spots.

It's not an illusion.

There is something which produces the appearance of these lines, and given the absolute abundance of linear features of all kinds on the surface of Mars -- some of which have never been adequately explained, especially the "searchlight" and other linear features that Mariner 9 revealed, many of which are no longer seen in orbiter images -- it seems worth investigating how the surface features, the Martian atmosphere, the terrestrial atmosphere and telescopic optics all interact to produce the appearance of "canali" as described by Giovanni Schiaparelli in 1877.

Cerberus Fossae, set of deep troughs with dark interiors, about 1600 km long

The image above is from Google Mars and shows some of the most prominent linear features on the surface, the Cerberus Fossae, a paired set of dark-floored trenches, some 1600 km from one end to another, that are still something of a mystery. I did a brief survey of "fossae" using Google Mars, and there are literally thousands of examples, dozens of them 1000km long or more.

The conventional wisdom is that relief on the surface of Mars cannot be detected with Earth-based telescopes even today, and that the various and numerous fossae on the surface are so narrow -- at most, a few kilometers wide, in the case of the Cerberus Fossae above, only about half a kilometer -- they cannot be resolved by Earth-based telescopes. While volcanoes and craters have long been seen on the surface of Mars, including the vast Valles Marineris canyons, they weren't recognized for what they were because it was impossible to detect surface relief. In fact, prior to spacecraft explorations, it was assumed that Mars had very little surface relief because none could be detected.

This is an unlabeled US Air Force map of Mars from 1962, which will give you an idea of how widely  the linear features of Mars were accepted prior to the arrival of spacecraft:

USAF map of Mars, c. 1962. Clickage will embiggen.

I got the map from this site where the development of Mars mapping is explored. Lowell's maps of Mars are not nearly as sophisticated but they are not dissimilar.

Lowell's map of Mars, c. 1894 for comparison:

Map of Mars drawn by Percival Lowell, c. 1894

Some observers have seen surface features very much like those recorded by Lowell throughout the history of telescopic observations, and some of them can be detected by modern CCD cameras. The appearance of linear markings on the surface of Mars is quite real. They are well and truly there, and they are there at many different scales.

In another post, I may get into the scale issue, for in some ways it may be a key to understanding what is going on.

[Today and tomorrow are travel days....]

Maintaining Stability in the Midst of Chaos

This post is mostly about Mars but no doubt will ramble all over the place as is my wont from time to time.

Three views of Mars from the Hubble Space telescope, March 10, 1997

There are so many images from the past few days, of the memorials for the new dead, of the Mars landing, of people just trying to hang on for dear life, of a planet incinerating, of despair, hope, grief and joy, that anyone's head would be spinning.

First to Mars for the thrill of adventure. For someone like me, this is really big-time exciting, though not quite as thrilling as earlier missions. They've become almost commonplace.

What we know of Mars today is nothing at all like the fantabulous Mars of Percival Lowell and Ray Bradbury; but neither is it much like the Mars of the 1972 revelations from Mariner 9.

Chesley Bonestell's vision of Mars, c. 1950

Portion of Noctis Labyrinthus from Mariner 9, 1972

Elysium "Pyramids" from Mariner 9, 1972,
used as an illustration in Carl Sagan's 1980 edition of "Cosmos"

Those images are burnt into my memory. They are the first to clearly show the presence of fluid-carved features on the surface, the first to delineate the Valles Marineris, the largest known canyon in the Solar System, and the first to clearly show the giant volcanoes of the Tharsis Ridge, particularly the one known then as "Nix Olympica," (Snows of Olympus) but now known as "Olympus Mons" (Mount Olympus), the largest volcano known in the Solar System, and on and on.

Mariner 9 had been preceded by Mariners 6 and 7 in 1969, and they had shown some of the same features, relatively clearly too (in some cases, the Mariner 6 and 7 images are higher quality than those of Mariner 9) but interpretation failed. For example Nix Olympica and the Valles Marineris are shown on the following full-planetary images from Mariner 7:

Mariner 7 (1969) images of Mars from 200,000 miles away

The circular feature in the upper center is the giant volcano; the squiggly business below it is part of what's known as Noctis Labyrinthus, highly fractured uplift area, and to the right of Noctis Labyrinthus is a dark feature with several dark spots around it which is the Valles Marineris feature together with associated canyons  and craters. Just barely visible are the tops of two of the three aligned Tharsis volcanoes which form a diagonal line at a 45 degree angle to Nix Olympica. The white patch at the bottom of the images is the extended South Polar cap.

All of these features and more are visible from Earth with the use of almost any fairly decent telescope, and they had all been reported and drawn -- though not necessarily photographed -- in great detail decades prior to the Mariner and later missions to Mars. These features are actually easily seen in Earth based telescopes; I've seen some of them myself.

The problem was -- and is -- one of interpretation. For example, "Nix Olympica." The name "Snows of Olympus" implies the presence of a significant mountain, which was how the feature was interpreted when initially identified and named; but the interpretation of the feature seen in the images above was that "Nix Olympica" was in fact a crater not a mountain at all. And the "snows" were clouds. Well, yes, there are clouds seen in this image, and Martian clouds were well known before space-craft explorations, but the original interpretation of a mountain is correct; the crater interpretation based at least in part on the Mariner 4 images which showed a heavily cratered Martian surface more like the Moon than the illustrations of a canal crossed smooth sand desert that had formed the basis of understanding the Martian surface prior to the arrival of Mariner 4 to take the first close-up pictures of the surface of Mars in 1965.

Mariner 4 image of the surface of Mars, 1965

But even here, where craters are obvious, interpretation is risky, and things in the image may not be quite what they appear to be. This is not a lunar surface, not even a lunar-like surface, but because there are craters at all, it was interpreted as lunar. You'll note in the lower left corner there is a straight line angled at about 30 degrees that extends about half way across the image; under certain conditions, it can appear to cross the entire frame. If this feature were visible from Earth (apparently it cannot be seen telescopically, however) it might well be interpreted as a canal. The formation is apparently a crack in the surface, of which there are very many over the entire globe, some of which are much longer than this one, and many of which evoke the "canals of Mars" as detailed by Percival Lowell.

According to standard interpretations, all of these features are associated with vulcanism and uplift. They do not form patterns of intersecting lines -- except when they do. And none of them are telescopically visible from Earth. According to standard interpretations, all of the "canals" so carefully delineated by Percival Lowell and testified to by other astronomers were optical illusions.

And yet the surface of Mars is crossed by literally thousands of linear depressions, some of them thousands of kilometers long, some of them roughly corresponding with the locations of Lowellian "canals."

How drole. Well, it would be if these linear features were acknowledged, but they are not. Few of them are even noted, though they be glaringly obvious in Mariner and Viking images especially. They are not "canals" in the sense that Lowell meant the term, but they are most definitely "canali" in the sense of "channels" as declared by Giovanni Schiaparelli. And there are thousands of them. Yet in standard Mars interpretation, there is essentially no mention of the abundance of cracks in the Martian surface, some of which indubitably mimic Lowellian canals.

Telescopic observers had also seen and recorded many craters on the surface of Mars well before any space-craft explored the surface, but these early records of craters on Mars tended to be ignored, not because the observations were necessarily in error (though they were definitely enigmatic) but because the dominant planetary paradigm was Uniformitarianism, and that implied that no planet with an erosive atmosphere (such as Mars) would preserve craters at the surface over the eons. Erosion would have long ago erased any evidence of abundant cratering, much as was believed to be the case with the Earth.

The following image from Mariner 4 shows another enigmatic linear feature that has defied interpretation for almost 50 years:

Mariner 4 Image of Craters in Atlantis region of Mars, 1965; linear feature at right edge of largest crater

What is it? It has not been located in later pictures of the area, or if it has, I haven't seen any announcement. From what limited scale information is available, it appears to be about 2.5 kilometers long, and .5 kilometer high, perfectly straight and perhaps 100 meters or so wide.

While this particular feature has not been located or identified in subsequent mapping and imaging of the area [see note below], there are many other enigmatic linear, circular and arcuate features on the Martian surface that defy ready explanation, so many in fact that there's a cottage industry of amateurs whose interpretations of these features as "buildings" of a Lost Martian Civilization are believed by many.

[Note: Now that I'm back doing vicarious Mars exploration again, I've made another "discovery." The Mariner 4 images above are of the same region; the upper Mariner 4 image is rotated 1/4 turn left and it has much lower contrast than the lower image. It appears they were taken at different times of day, but that's not possible as the Mariner 4 mission was a fly-by, not an orbiting mission. The upper image reference number is PIAO2979 while the lower image reference number is PIA02980, suggesting they were acquired one after another. The images were acquired with a miniature television camera most likely using different filters. For example, the upper image may have been taken through a green filter while the lower one was possibly acquired through a red filter. Interestingly, in the catalogues of Mariner 4 images, the first image is the only one that is referenced. The second one is not referenced in the catalogues and is almost never referenced at all. The crack that appears in the upper image is almost always referred to as a "ridge" -- as that was how it was described at the time the image was first released. The crack is part of the Sirenum Fossae ("fossae" means "fractures" or "ditches" not ridges.) The crack also appears in the lower image (just barely visible from the lower right corner rising at a 60+ degree angle toward the upper center.) The small linear feature noted in the lower image is barely visible in the upper image, but it is not linear. It appears to be more oval. A comparison was posted at Malin Space Science Systems in 2007 which shows the 1965 image together with a 1978 Viking Orbiter image of the same region at approximately the same scale:

Mariner Crater, Mars, as imaged by the Viking Orbiter, 1978

Mariner 4 crater image rotated.

The crack is clearly visible, extending straight through the bottom of the crater. A peninsula and a small ovoid hummock is visible on the lower rim of the crater that roughly corresponds to the oval feature in the upper Mariner image and to the location of the linear feature in the lower Mariner image. There is no sign of a linear feature in that location in the Viking image. It may be an imaging artifact. Or... ?]

The signs are that there has never been a civilization on Mars, "Lost" or otherwise, nor is it particularly likely there could be one, at least not one we would recognize. The surface of Mars is apparently extremely hazardous and potentially lethal to living things such as our own sweet selves and presumably to any potential aliens, let to alone bugs and microbes and such like. Not only are temperatures and atmospheric pressures typically too low for comfort (! to say the least), there are no ready resources -- at the surface at any rate -- to support biology on any but the simplest scale, and even then, there are many factors that argue against even the most modest biosphere on Mars.

That doesn't mean there is no biology on Mars. If biology on Earth can adapt to the most severe circumstances, there's no reason it couldn't do so on Mars. So the biology question should remain open until there is actual evidence one way or another as opposed to elaborate interpretations of ambiguous data. In fact, it has been suspected for some time that if biology is ever proven to exist on Mars, it will likely be in the form of microbes that were brought to Mars as contaminants on spacecraft launched from Earth!

Be that as it may, it has long been the practice in the planetary science community -- at least since Lowell -- to make broad and expansive interpretations of very limited and ambiguous data, and for those interpretations to stand for many years despite conflicting data. I've often called Mars "The Mimic Planet," and "The Planet of Deception." Much of what we see on the Martian surface mimics what we might see in terrestrial deserts, and yet, it's not really the same at all. Some of what we see mimics other features, whether canals or something else, and that mimicry can easily lead to erroneous interpretations, such as that of Nix Olympica as a crater rather than a mountain. There are many circular features on the surface of Mars that quite likely aren't impact craters but are interpreted as such because it is customary to interpret circular features on Mars as impact craters even if there are indications the feature formed through other means (such as undermining and collapse from below).

Geysers of some sort are not a newly theorized or even newly discovered phenomenon on Mars, but their broad acceptance by the planetary community seems to date only from 2006, whereas I and others were seeking them out as early as 1996 when the Mars Global Surveyor/Mars Orbital Camera images started being returned. It seemed natural that there would be surface geysers on Mars under certain circumstances. The surprise was that when geysers were found, they were in abundance, near the south pole, and were "sand geysers" rather than fluid geysers, caused by pressure release from below a layer of clear carbon dioxide ice warmed by the springtime sun.

Greg Orme is an Australian amateur Mars enthusiast whose tireless inspection of MOC images has resulted in numerous discoveries over the years. He was dogged and determined and I wouldn't doubt he's inspected every one of the hundreds of thousands of images returned by the MOC and other orbiting cameras. He's found hundreds if not thousands of "spiders," and these spiders are often seen as the remnants of the geysers that occur every Martian spring.

r1001457f

Above is one of my crops of the defrosting Inca City region near the south pole showing some of the spiders and some of the evidence of geysering (there don't appear to be any active geysers in this view.)

Note: Inca City is an enigmatic formation discovered in 1972 by Mariner 9 near the south pole. This is an image of it from the Mars Orbital Camera:

Inca City, Mars

It's considered to be a remnant of a buried crater due to its somewhat circular appearance, but it is not certain what caused the rectilinear features. Ice is suspected, but how the formation occurred is deeply mysterious. There are many somewhat similar features in many places on the surface, some of which resemble what a turbulent fluid might look like if it suddenly froze.

The geysering phenomenon got a good deal of coverage in 2006 when planetary scientists broadly accepted it. This Wikipedia article covers most of the story pretty well. This Mars Anomaly Research article from 2005 is quite complete, and it seems to be based in part on my original discovery of active geysering (c. 2001) as well as later images. Finally, this Mars Enigmas article from 2006, while somewhat confused and confusing, gives a pretty good overview of the phenomenon both from a popular and a scientific point of view.

Of course, none of this has anything at all to do with the Mars Curiosity's explorations in Gale Crater going on now. Gale shows evidence of once hosting a lake. The idea of ancient standing liquid water is far more exciting to planetary scientists than is the notion of presently active sand geysers bursting through a crust of solid CO2 (how boring.)

A sand geyser is probably not the most likely place to find present or past biology on Mars. Since the phenomenon is apparently both extensive and energetic, it's probably wise to stay out of the immediate vicinity of eruptions in any case. After going to all the trouble to land on Mars (and the Curiosity landing was spectacular), it wouldn't do to have the craft promptly blasted to smithereens by the nearby eruption of a sand geyser! We may never send landing craft close to an erupting geyser field.

There is enough chaos in our environment as it is.

On the other hand, Gale Crater, somewhat south of the equator, is bound to be calm and stable, much like Spirit''s stable location in Gusev Crater not all that far away (also thought once to have been a lake).

There will be discoveries no doubt, but more than likely, they will perpetuate rather than solve the biology enigma, and they will no doubt fuel more speculation about the poorly understood nature of the Martian surface.

I look forward to results!

Full resolution Curiosity heat shield on the way down. Courtesy NASA

Wheee!
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A note on how Mars images get manipulated.

The first image is from Viking 2, Mars winter 1976, altered fairly recently to resemble surface images from Pathfinder, Spirit and Opportunity.

Viking 2 lander image, 1976 altered to resemble more recent images from the surface of Mars

The second image is more or less what the picture looked like until it was layered with a sort of reddish "dust" which is widely believed to make the sky more or less pink more or less all the time, and thus make the surface appear quite red.

Viking 2 lander image, 1976, "dust" layer removed

The sky is pale blue, the ground ruddy but not particularly red, the rocks are multicolored, and white frost is clearly visible on the ground.

There are whole websites devoted to NASA'S  endless manipulations of the colors of Mars. At one time, there was wide circulation of an image from Viking 1 with a green sky and very red surface. The green sky picture is now only available with permission. That picture was recalibrated before the Pathfinder landing to look like this:

Viking 1 lander picture of Big Joe
Still a little bilious if you ask me.

Better