The “Pure Michigan” ad campaign should wait until they’ve replaced ALL of the lead pipes in Flint. Until then, the whole thing is just an exercise in hypocrisy.
Purify Your Water First, Michigan!
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Tag Archives: water
A Proposal: An Ice-Tunneling Lander to Explore Extraterrestrial Sub-Surface Oceans
We have found compelling evidence for the existence of several sub-surface oceans in various places in our solar system. The most well-known of these bodies of liquid water is under the ice crust of Europa, a moon of Jupiter, with others located elsewhere. These oceans are logical places to look for signs of past or present extraterrestrial life. However, we have yet to obtain a sample of any of these oceans for analysis. It is time for that to change, but not without taking precautions to avoid damaging any such life, should it exist.
Europa (source: NASA)
What follows is my idea, freely available for anyone who wishes to use it, to safely obtain and analyze such samples. These ice-tunneling probes could be ejected from a larger lander, or simply dropped directly onto the surface from orbit. This would be far less expensive than any sort of manned interplanetary exploration. Exposure to vacuum and radiation, in space, would thoroughly sterilize the entire apparatus before it even lands, protecting anything which might be alive in the ocean underneath from contamination by organisms from Earth.
In this cross-sectional diagram, the light blue area represents the ice crust of Europa, or another solar-system body like that moon. The ice-tunneling lander is shown in red, orange, black, yellow, and green. The dark blue area is the vertical tunnel created by the probe, shown shortly after tunneling begins. As the probe descends, the dome shown in gray caps the tunnel, and stays on the surface, having been previously stored, folded up, in the green section of the egg-shaped probe. The gray section is designed as a geodesic dome, with holes of adjustable size to allow heat to escape into space. An extendable, data-carrying tether connects the egg-shaped tunneling module to the surface dome. Solar-energy panels and radio transmitters and receivers stay at the surface, attached to the gray dome.
The computers necessary to operate the entire probe are in the yellow section. The black section that extends outward, slightly, from the body of the tunneler would contain mechanisms to obtain samples of water for analysis. The orange section is where actual samples are stored and analyzed.
The red part of the tunneler is weighted, so that gravity forces it to stay at the bottom. It is designed to heat up enough to melt the ice underneath it, allowing the entire “egg” to descend, attached to its tether. Water above the tunneling probe re-freezes, sealing the tunnel so that potentially-damaging holes are not left in the ice crust of Europa. The heating units in the red section can be turned on and off as needed, to slow, hasten, or stop the probe’s descent through the crust.
Oceans in other places in the solar system might require certain adjustments to this design. For example, Ganymede, another moon of Jupiter, is far rockier than Europa. If this design were used on Ganymede, the tunneling probe would likely be stopped by sub-surface rocks. For this type of crust, the probe’s design could be modified to allow lateral movement of the tunneler, in order to go around rocks.
Ganymede (source: NASA)
On Europa, Ganymede, and elsewhere, one limitation of this design is imposed by the maximum length of the tether. We would not want to go all the way down to the subsurface oceans with the earliest of these probes, though. A better strategy would be to only tunnel part-way into the crust at first, capturing liquid samples of water before refreezing of the ice. After all, this ice in the crust could have been part of the lower, liquid ocean at some point in the past, and it should be analyzed thoroughly before heat-tunneling any deeper. The decision to make the tether long enough to go all the way through the crust, into the subsurface ocean itself, is not one to make lightly. It would be best to study what we find in molten crust-samples, first, before tunneling all the way through the protective crusts of these oceans.
Earth’s Oceans’ and Continents’ Relative Surface Areas, Analyzed, with Two Pie Charts
I’ll start this analysis with a simple land/water breakdown for Earth’s surface:
The two figures in the chart above are familiar figures for many — but how does “land” break down into continents, and how does “water” break down into oceans, as fractions of Earth’s total surface area? That’s what this second chart shows.
With continents, I placed them on the chart to make it easier to see physically-connected continents as sets of adjacent wedges of similar color, separated only by thin lines. The most obvious example of this is Europe and Asia, which are considered separate continents in the first place only for historical reasons, not geographical ones. Combine them, into Eurasia, and it has 36.3% of Earth’s total land area, which is (36.3%)(0.292) = 10.6% of Eath’s total surface area. Even then, Earth’s three largest oceans (the Atlantic, Indian, and Pacific Oceans) are each larger than Eurasia.
There are other naturally-connected continents, albeit with much smaller land connections — narrow enough for humans to have altered this fact, only a “blip” ago on geographical time-scales, by building the Suez and Panama Canals. In the case of the Suez, its construction severed, artificially, the naturally-occurring land connection between Eurasia and Africa, and the term “Afro-Eurasia” has been used for the combination of all three traditionally-defined continents. Afro-Eurasia has 56.7% of Earth’s land, but that’s only (56.7%)(0.292) = 16.6% of Earth’s total surface area. That’s larger than the Indian Ocean, at (19.5%)(0.708) = 13.8% of Earth surface area. However, both the Atlantic Ocean, at (23.5%)(0.708) = 16.6% of Earth’s surface area, and the Pacific Ocean, at (46.6%)(0.708) = 33.0% of Earth’s surface area, are still larger than Afro-Eurasia.
The Pacific Ocean alone, in fact, has a greater surface area than all of Earth’s land — combined.
The other case that can be made for continent-unification involves North and South America, since their natural land connection was severed, only about a century ago, by the construction of the Panama Canal. Combine the two, and simply call the combination “the Americas,” and that’s 28.5% of earth’s land, which is (28.5%)(0.292) = 8.3% of Earth’s surface area. (I didn’t simply call this combination “America” to avoid confusion with the USA.) The Americas, even in combination, are not only smaller than each of Earth’s three largest oceans (the Atlantic, Indian, and Pacific), but also smaller than Afro-Eurasia, or Eurasia — or even Asia alone, by a narrow margin.
By the way, there are lots of things that don’t show up on the second chart above: islands, inland seas, lakes, rivers, etc., and there’s a good reason for that: on the scale of even the larger pie chart above, all these things are so small, compared to the oceans and continents, that they simply aren’t large enough to be visible.
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I painted this in 2002, using acrylic on canvas.
On the Varieties of Water
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As many people know, there is more than one type of water. For example, the term “heavy water” often refers specifically to D2O, with “semi-heavy water” referring to DOH. Add tritium to the mix, and the new combinations possible — all radioactive — include HOT, DOT, and T2O. Along with diprotium oxide, plain old H2O, that’s six isotopic variants of this one simple compound.
However, that six needs to be multiplied by three. Why? Because there’s one set of six that includes an oxygen-16 atom (the usual kind), and another six for oxygen-17, and one more for oxygen-18, for a total of eighteen. So far. Both oxygen-17 and -18 are stable, and occur in nature, although they are both of very low abundance.
Eighteen kinds of water, half of them radioactive? No, that’s not quite enough. If the radioactive isotope of hydrogen is included, then so should be the radioisotopes of oxygen. That would include oxygen isotopes with mass numbers from 13 to 15 (add three more sets of six, or 18, which, when added to the original 18, gives a running total of 36), and 19 to 24 (add six more sets of six, or 36 more, to the 36 we just had, and we’re now at 72).
To leave it at 72 isotopic varieties of water is not necessary, but it is reasonable. Yes, there is oxygen-26, but with an estimated half-life of 40 nanoseconds, it isn’t reasonable to expect there to be time for it to form a water molecule. Could it happen? Possibly — but it’s extremely unlikely to ever be observed. For oxygen-12, the story is similar, but with an even shorter nuclide-lifetime than that of O-26.
Additional isotopes of hydrogen have also been detected, with mass numbers from 4 to 7, but they decay even more quickly than O-26 as well.
72 it is, then, counting nothing with a half-life under a millisecond. This is the sort of thing that happens when math compulsives think about chemistry a bit too long.
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