Aloha Mars - The Advanced Course
Honolulu - Feb 13, 2004
My friend Dr. X is really getting interested in Mars. Yesterday he challenged me about those mysterious spherical beads at the Opportunity landing site. "The MER guys are struggling to choose between a bunch of wildly different explanations. I suppose you have an instant snap analysis of them based on your crazy Aloha Mars model that relates everything on Mars to something in Hawaii."
"Sure. They are lava spherules ejected by a violent late-stage volcanic eruption. It's intuitively obvious."
"How does Aloha Mars lead you to that conclusion? There is nothing like those spheres anywhere in Hawaii as far as I know. Certainly not between your house and the nearest strip mall, which seems to be the limit of your field expeditions."
"I sense that you are a thoughtful open-minded person who is ready for graduate-level instruction in Aloha Mars doctrine. So here is a more advanced method for instant snap analysis of Mars:
"Mars is intermediate between Hawaii and the Moon in most physical properties (gravity, air, age, volatile abundance). So we Aloha Martians always look for some combination of Hawaiian and lunar processes to explain any odd details on Mars that don't have an exact local analog. I'm sure you are familiar with the volcanic glass spheres that occur on the Moon."
Dr. X looked insulted. "I've given hour-long lectures on them, as you know perfectly well. Those Mars beads do look a little bit like the pyroclastic glass spheres in the Apollo samples. But if you look closely, there are a lot of differences. For one thing, the Mars spheres seem to have bubbles in them."
"Like I said, Mars is halfway between the Moon and Hawaii. The air pressure on Mars was enough to prevent the gases from boiling out completely like they would in the lunar vacuum. Also the flight time was probably less on Mars due to higher gravity and air drag. In Hawaii, the same effects are magnified many times. Blobs of magma usually strike the ground still molten in a limited region around the vent, so you get a lava lake and flow."
"Yes, the air and gravity would have a strong effect on flying magma blobs. On the Moon the volcanic beads are usually perfect spheres. A lot of the Mars beads are not quite round, which could be due to air drag effects."
"You're becoming a Mars expert faster than I expected. But then as a Moon geologist living in Hawaii, you start out with a big advantage over most people."
"Another thing I noticed is that those Mars beads seem to all be some kind of bland grey color. The Moon beads come in a variety of bright colors. Remember that orange soil at Apollo 17?"
"How could anybody not remember it? The lunar science community made a gigantic fuss over that orange soil because they said it must be a sign of water on the Moon. It was a huge disappointment when the samples turned out to be bone-dry glass."
Dr. X looked wistful. "If that soil had really been rusty, we might have been able to fund a real Moon program. We might be having this conversation at a lunar base. We might..."
I had to get Dr. X back to reality. "You guys let your wishes override your judgement then. The Blue Martians are making the very same mistake right now. They instinctively emphasize the wettest possible explanation of anything on Mars and downplay the dry explanations. The public relations people slant things even more when they write the press releases.
"Then the so-called space journalists take the press release and spin it even more toward water. By the time the public gets the news, it is distorted beyond recognition. It's no wonder that the MER rover team have to spend half of each press conference slapping down quack theories about those beads being fossils or eggs."
"Let's get back to Aloha Mars here. These beads don't look like glass. In fact I hear they are made of hematite. That's clearly some kind of water alteration product. Isn't that a strong argument for the Blue Mars interpretation that this place is a lakebed?"
"Not according to the Aloha Mars model. If you look around Hawaii, you see that everything is subject to water alteration, not just stuff submerged in water. Look at any graduate student's car. Most of them are well on the way to being fully altered from pure iron to various iron oxides like hematite. The hot humid air here alters volcanic rocks almost as fast. Try to find a fresh unaltered roadcut exposure sometime."
"So Mars once had a Hawaii-like atmosphere? Sounds like Blue Mars propaganda to me. And why is the hematite only at one spot? I can remember when the Blue Martians said the whole planet was altered to hematite. It was a big mystery when we actually looked for it from orbit and mostly didn't find any."
"This particular place seems to be very odd and different from typical places on Mars. So it probably is the result of a rare combination of factors. I think this ashfall might have fallen on a region rich in permafrost. The heat conducted down from the ashfall would gradually melt the permafrost, so steam would constantly be rising up through the deposit, maybe for a long time after the eruption stopped. This particular volcanic deposit could actually have been subjected to Hawaii-like conditions for many years. So there is plenty of time for Hawaii-like alteration of the glass beads into weird minerals. They're probably altered all the way through, since they are all pretty small."
"This Aloha Mars model sounds pretty useful. But I see a real political problem with it. It makes Mars sound pretty boring."
"Here's a news flash: Mars is boring. I can only think about Mars about half an hour at a time before sheer boredom makes me quit and go study something entertaining, like French military history. Why do you think NASA has to surround each Mars mission with a blizzard of hype about water and life? If you saw those Spirit pictures of bland featureless desert and were told they were places on Earth, would you give them a second glance?"
"The Opportunity site is not so bad. They were really lucky to land in that crater right next to bedrock."
"After the rover leaves the crater, prepare for more bland featureless desert. In another week or two they will be running out of new things to study. In a month, even fanatical Mars Cadets will lose interest. Fortunately, we have a long series of future Mars missions in the pipeline. The Mars water hunt has years left to run -- unless the Aloha Mars model becomes generally known."
Dr. X shuddered with horror. "Elvis forbid!! My lips are sealed. We rocket scientists have to all hang together, or all be hanged separately."
Jeffrey F. Bell is Adjunct Professor of Planetology at the University of Hawai'i at Manoa. All opinions expressed in this article are his own and not those of the University.
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Opportunity Sees Tiny Spheres in Martian Soil
Pasadena (JPL) Feb 09, 2004
NASA's Opportunity has examined its first patch of soil in the small crater where the rover landed on Mars and found strikingly spherical pebbles among the mix of particles there. "There are features in this soil unlike anything ever seen on Mars before," said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the science instruments on the two Mars Exploration Rovers.