Planetary News
I just joined THE PLANETARY SOCIETY, and will receive The Planetary Report soon. My timing may be good, for there have been a couple of interesting developments in planetary science.
The first is a major dust storm on Mars. Dust storms are nothing new of course. One blanketed the entire Red Planet in 1971, threatening to veil the Martian surface from the US probe Mariner 9. This time, however, the presence of functioning landers on Mars enables researchers to study such an event in greater detail. The current storm has been associated with a decrease in atmospheric pressure.
The other development is the discovery that Mercury has more polar ice than previously thought. Despite the searing heat of Mercury's equatorial zone, its poles are cold enough for ice because the innermost planet has essentially zero obliquity. Without axis tilt or seasons, the poles remain in perpetual darkness and cold. They may contain enough water to submerge Washington D.C. two miles deep. This is interesting because it suggests future colonization of Mercury may be possible, at least at higher latitudes, where water is available and solar heat less terrific. Conceivably, some of the ice may have melted and entered underground reservoirs, where life may exist--though that's far-fetched. In any case, I hope the next Planetary Report will provide interesting details of both developments.
The first is a major dust storm on Mars. Dust storms are nothing new of course. One blanketed the entire Red Planet in 1971, threatening to veil the Martian surface from the US probe Mariner 9. This time, however, the presence of functioning landers on Mars enables researchers to study such an event in greater detail. The current storm has been associated with a decrease in atmospheric pressure.
The other development is the discovery that Mercury has more polar ice than previously thought. Despite the searing heat of Mercury's equatorial zone, its poles are cold enough for ice because the innermost planet has essentially zero obliquity. Without axis tilt or seasons, the poles remain in perpetual darkness and cold. They may contain enough water to submerge Washington D.C. two miles deep. This is interesting because it suggests future colonization of Mercury may be possible, at least at higher latitudes, where water is available and solar heat less terrific. Conceivably, some of the ice may have melted and entered underground reservoirs, where life may exist--though that's far-fetched. In any case, I hope the next Planetary Report will provide interesting details of both developments.
posted by starman at 4:47 AM
24 Comments:
The ice at Mercury's poles is news to me, but perhaps not surprising. Similarly, our moon also seems to have ice at its poles in crater's perpetually hidden from sunlight. And Mars, Jovian moons, etc. Of the rocky inner planets, only Venus is currently the exception under its dense clouds and searing surface temperatures.
The likely ubiquity of water and ice in the inner solar system was brought home to me about 25 years ago (long before it was discovered on the Moon and now Mercury) when we were on a snow trip in the Sierra Nevadas and a neighboring lodge had a lecture by a NASA scientist. He told the small audience it was now believed that Earth's oceans were mostly the result of massive bombardment by comets early in Earth's formation when the planets were all being formed by larger bodies colliding with and gobbling up smaller ones.
That's when the light bulb went off in my head and I suddenly realized that if that was true of Earth, then it was true of all the planets and moons, including our Moon, Mars, Venus, and Mercury.
In addition, he showed how NASA had also sent U-2 spy planes high into the atmosphere with scoops and filter paper to capture micrometeorite material while still floating around atop the atmosphere, i.e., still in its pristine state. Much of it resembled popcorn balls, consisting of small inorganic silicate material glued together by a tarry organic material.
This organic material from the formation of our solar system is still raining down on us, and would have been in much greater quantities while proto-Earth was accreting debris. Again, the same would be true of the other planets. This would be some of the raw organic components in the water ocean soup that led to life on Earth.
In the early days of the solar system after main accretion, it is thus conceivable other planets like Mercury, Venus, and Mars, even the moon, would have evolved some sort of bacterial life before they lost their oceans and atmospheres (or got buried under their atmosphere like Venus). Thus finding life on Mars in some form again would not be a surprise to me.
Great to see your post here, DR! I think that Mercury, at least, lost its atmosphere and most of its water long before bacteria could evolve, except perhaps in underground niches.
I'm glad you joined the Planetary Society--have you received their Report yet? I too was thrilled that they found water-ice on Mercury; that will make colonization easier although we must also develop the capacity to transport cubic miles of H2O through millions of miles of space, which will make settlement possible even on barren worlds. Also even the extreme temperatures in Mercury's lower latitudes won't make settlement too hard, because (for one thing) if you just dig down a hundred feet or so (I'm guessing but this seems reasonable) you'll find moderate temperatures--but there'd be no need to live in underground caves because we could achieve the equivalent cooling simply by spreading a few meters of Mercurial regolith atop the roofs of our buildings there. And then too, as I've pointed out for Venus, we could use giant refrigeration machinery. Another fascinating project will be to build canals (much more romantic than mere pipelines) to transport
H2O from Mercury's poles to all over its surface so as to build cities everywhere! I love to dream of this stuff and I think the Planetary Society also does some thinking about colonizing the planets like this, don't they?
I think the odds against life (past or present) on Mars are a million to one but multiplying that by a billion similar planets in our galaxy (which seems possible, maybe even conservative although it does seem strange or slightly disappointing to me that they haven't found many anywhere-near habitable planets yet), it seems most likely that there is life on other worlds in the Milky Way, and multiplying that by the
10**11 or 10**12 galaxies in the Universe, it seems almost certain to me that there's life elsewhere.
PS I just had another thought which is that we wouldn't even need to cover our roofs on Mercury with too much dirt--just mirrors or snow-white tiles would do the job of keeping the sun out, combined with exposure of living areas to the blackness of space in all directions except where the sun is--which would have a powerful cooling effect.
Lol, pipelines would be an absolute necessity, since Mercury has no atmosphere. The water would quickly evaporate, indeed boil away, or, on the night side, just freeze. I haven't got THE PLANETARY REPORT yet.
Evidence of water ice on Mercury has been known for over 20 years; I remember discussing it with ex-lexer David Sims, who was at first skeptical. Btw he used to be a man of the far-left. In recent years, however, he's become a racist.
No, really, one of my favorite imaginations is of canals on Mars--and Mercury would be similar--where the obvious key is that they would have to be COVERED--encased in glass tubes like 15 feet in diameter, where people could picnic on the grassy banks of the little stream running through, while gazing up at the pink sky on Mars or the starry black sky on Mercury--these scenes might only occur along a few scattered kilometers of the whole many-thousand-km pipeline; but I think it's beautiful. Of COURSE the water would have to be heated and cooled, but that's easy and cheap, relatively
Sounds interesting but glass tubes would have to be able to stand up to great temperature extremes, and shifts. They'd only be possible at high latitude on Mercury, to avoid cooking the people inside, and low latitude on Mars, to avoid constant freezing.
Well, the first example that came to my mind was the glass used in light bulbs--that seems to show that glass can withstand intense radiation in addition to at least one-atmosphere of pressure differential. (Also, we might find it best to use some other transparent substance, such as maybe quartz, mica, Lucite, or diamond--did you hear about that planet they found recently whose mantle consists of diamond? Imagine billions of cubic miles of solid diamond!)
Also, on Mercury, you would only need to shield the picnickers from a portion of the sky. For example, in the morning, we would need to put up a sheet on the east side of the tube (assuming the sun rises in the east on Mercury--I'm not sure whether it does?); for noonday picnics, we need only put a sheet over the top of the glass tube so that you could still view scenes and sky east and west, etc.
BUT to go back to something I said earlier, the hard part of transporting cubic miles of ice across millions of miles of space is not the journey, but is how to land it safely on the planet where its needed--Venus, say, or maybe even Mercury if the cubic miles of H2O it has turn out not to be quite sufficient for the billions of people who might wsant to live there some day and their farming and heavy industries!
It would be tough to transport ice to Venus. Unless it's in a container--which limits the amount that can be transported--it'll be like a comet, shedding a lot of volatile substance as the sun boils it away. The best solution may be to use photosynthesizing bacteria to split O2 from carbon in CO2, then transport hydrogen from Jupiter to Venus, so it can combine with the oxygen to form water. Of course we'd have to first lower Venusian temperatures e.g. by shading the planet somehow.
I doubt it'll suffice to block out the morning or noon sun on Mercury. The "day" lasts about a month, and solar heat is several times greater than here--which as we know, can get bad enough--so heat buildup will be horrendous by afternoon, no matter what you shield.
I find it fascinating to think about these things! Remember how the artist Christo used to cover whole square miles of land or islands or whatever with sheets of plastic I guess it was? That makes me think it shouldn't be hard to wrap a cubic mile of ice; also I remember how back in the 1940s engineers developed plans to transport ice from Antarctica to places that need water (or ice? I don't seem to remember that part). The key to being able to ship it across the warm oceans was to wrap it in plastic or something so that it wouldn't lose its solid form by losing its (inevitable) melt-water (still cold) to the open sea. But really, I think, the most difficult part of landing ice on Venus would be slowing it down from its high interplanetary velocity--but that is actually only a matter of having gigantic rocket engines, and the key to that is really just obtaining the energy--and the key to THAT is thousands/millions of square miles of solar panels! On Venus, I would place the ice 40-50 miles up above the surface (in a giant tower--can't remember if I've talked here about how to build colossal towers on Venus?), where the atmospheric temperature is about 0 C; or keep it at that altitude by means of giant "heHeH" (my acronym for heated Helium/hydrogen) balloons until it can be brought down to the surface as needed in small quantities. OK I haven't given these details too much thought.
On Mercury, the important thing is that there's no atmosphere, so that the sunlight doesn't get diffused to come down from all over the sky. Therefore, if you are in the shade, your body is radiating its heat into outer space just as if it were a winter's night; that's why I think that just a partial shield of the glass tube would work--you'd probably want to combine it with a warm artificial breeze inside the tube, I guess.
Also I think that all that CO2 on Venus might someday be a super resource for building artificial O2 atmospheres on the other worlds of the Solar System.
Might not be necessary to cool Venus off because cool temperatures are already available there, high in the atmosphere.
Yes, these topics are fascinating. I don't know if a partial shielding of the glass tube would suffice. Glass conducts heat, and so does the ground. It would be one thing if the heat were no greater than it is here or on the moon. But Mercury experiences solar heat several times greater.
We'd have to cool the surface of Venus for significant colonization to be possible, and much of the available oxygen from splitting CO2 would be needed to make water i.e. combined with hydrogen, to make oceans on Venus.
Well, I would call a population of 1 billion a significant colonization of Venus, and that many people could easily be fit into 1 million sq mi, with plenty of open space to spare. And that would be just 1/2 of 1% of Venus's surface--so it really shouldn't be necessary to cool off the whole planet!
I agree that you'd have to consider the ground conductivity of heat, as well as reflected light from hills and mountains, etc., in figuring out how much shielding the glass tube would need. Interesting to think about, I don't know the answer offhand!
One great advantage of Venus, from the point of view of colonization, is the fact its gravity is practically the same as Earth's. Elsewhere, on Mercury, Mars etc, much lower gravity might result in brittle bones or even very tall natives i.e. those born there.
I remember what Lovelock said, that to be lasting, life must cover a planet extensively i.e. essentially the whole planet must be habitable. Otherwise, there wouldn't be sufficient oxygen production, among other issues. I think we'd have to cool off all of Venus.
I'm not familiar with Lovelock's work, can you give me a reference? I assumed we could get all the oxygen we'd need on Venus by electrolysis of the CO2 but I really don't know the physics or economics of that, or how it would compare with using bacteria to do the job. But as I pointed out, at high levels, the atmosphere on Venus does have mild temperatures, to support any bacteria, but maybe they'd require other things like water, organic matter, trace minerals, a solid base, soil, protection from the sulfuric acid, or something?
I've been surprised at how astronauts or cosmonauts have been able to spend years in space I guess with no bone problems or at least easily remediable (have you heard anything different about this?). Anyhow if need be, we could put spin-chambers all over the Moon, Mars, Mercury, etc., to provide artificial gravity whenever people may want it! But how would we bring tall, frail-boned ETs from low-g worlds to our Earthly civilization? Perhaps they could survive by floating in water. (I wonder if something like that might enable us to survive on Jupiter [where I envision us living in heHeH balloons in the atmosphere--it could be a beautiful, spectacular environment!]) This brings me to another interesting question, which is how to incorporate dolphins, whales, etc., into our civilization, especially for interplanetary travel in the Space Age?
Remember the Gaia hypothesis? If memory serves, Lovelock was the theorist behind it. I'd assume bacteria would be a much more efficient way to split CO2 than electrolysis. Where's the electricity going to come from? Bacteria multiply on their own.
I've heard of bones getting brittle, and people losing calcium in space, due to low gravity. Dolphins will have to wait a long time. Tough organisms like lichens may be among the first earthly life to go to Mars.
Anyhow I think it's good that we mere amateurs have come up with at least two different approaches to colonizing Venus, so that it seems possible that a few thousand teams of engneers might welll be able to think up a bunch of possible methods, some of which might actually turn out to be practical or even profitable (not to private enterprise, of course, but to make revenue for the State...). Anyhow so have you gotten any magazines or reports from the Planetary Society and do you think that they would be interested in discussing such questions as to how colonize the Solar System?
And as for dolphins, they, like especially the whales, will certainly be a challenge--but I love challenges! I mean if we can integrate them into our civilization, it would certainly be worthwhile to do so! Like just think of how much cats and dogs and horses, for example, have added to our culture without half the brains of a cetacean!
Lichens not so much but still worthwhile, I'd say. Mightn't they perhaps help build soil? That reminds me that we'd want to send nitrogen-fixing bacteria to Mars among so many other things.
Of course Planetary Society members are interested in colonization, terraforming, etc but I haven't heard from them yet. I hope my membership fee wasn't lost in the mail....
I just got THE PLANETARY REPORT. The most interesting thing, to me, is the excellent, close up pic of the central peaks in Copernicus crater. I've seen them many times in my small telescopes but not this well, lol. Boulders from the peaks have fallen to the crater floor. I assume that happened periodically due to tremors following impacts later than those which formed Copernicus. Aristarchus is an example.
Cool. When I see pictures of lunar (or other otherworldly) terrains, I like to imagine cities and suburbs being built in those landscapes. Mostly the nicest places to put cities, I think, would be on crater rims--especially if or where one crater rim crosses or runs close to another crater rim. Atop crater central peaks would be another nice place, and amongst the boulders that may have tumbled down off the peaks would be yet another interesting cityscape! If I ever get time to get back to painting, those are some of the scenes I'd like to do. I mean, just because we build nice suburban homes in such places doesn't mean we can't have sci-fi type adventures there too!
Now that lunar ice is known, such dreams may become reality, albeit not soon. The report says some boulders are as big as 20 or 30 meters wide. I bet landslides are dangerous even under low gravity conditions, lol.
Yes, well, as long as such dreams are credible they offer the prospect of unifying humanity in progressing towards their realization for all even if it may take a hundred years, I mean that prospect makes me feel happy, at least so maybe it will inspire others to cooperate as well.
Yeah, 20-30-meter boulders could be scary even if the gravity were so low that they would fall even just a few feet a minute or a hundredth of an mph. One thing I like to dream of is playing among the ice boulders of Saturn's rings. Intuitively, one fears that such play would instigate a sudden collapse, but that might not be the case, but it probably WOULD result in boulders colliding at very low speeds--still dangerous!
It occurred to me that Copernicus crater is very old. The photo of the central peaks showed many smaller craters, which took a long time to accumulate.
Yeah, I guess that Copernicus was formed in the "Late Heavy Bombardment"? Has the rate of crater-formation been relatively constant in the billions of years since then? Or has it followed some kind of perhaps exponentially decreasing curve?
I think it fell off sharply at the end of heavy bombardment and continued at a more or less constant rate since hence the use of crater count data as the basis of age estimates.
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