If this had happened, say, thirty years ago; it would have been an occasion for great nationalistic clucking and crowing. These days, people notice the irony, perhaps. More likely, with the tightening of budgets for space everywhere, the loss of any major expedition is viewed with dismay.

Mars is a difficult target. More than one-half of the missions have failed, some like the recent Russian Fobos-Grunt project fail even before leaving Earth orbit. Others, such as the NASA Mars Polar Lander crashed into the Martian surface. It’s known as the Mars Curse, but in truth it’s the complexity of the journey and the various requirements of landing on a major planet that demand near perfection in every detail, which is difficult to achieve.

Mars is often cited as the most important destination for human space exploration. Conceptually, this is certainly so; Mars has more to offer humanity – including possible colonization – than any other planet or moon. However, Mars Curse or not, it’s clear that Mars is logistically very difficult – beyond our means (money and technology) at least for the time being. What I just wrote can be vociferously disputed, but I wouldn’t take any bets on a manned Mars mission happening within two decades.

Zircon is a very common trace mineral in many kinds of rocks and soils. It’s relatively hard, crystalline material that, among other things, often contains trace amounts of radioactive elements uranium or thorium. The radioactivity has made it possible to date zircon with considerable precision, leading to the discovery that some zircons were formed about 4.4 billion years ago, the oldest known minerals.

Scientists at the New York Center for Astrobiology at Renssalaer Polytechnic Institute reasoned that zircon might also be used to determine what kind of gasses were present in the magma that formed the zircons. That, in turn, could reveal what gasses were escaping from magma that reached the Earth’s surface and were contributing to the formation of the atmosphere. Their results, published in Nature [30 November 2011, paywalled, The oxidation state of Hadean magmas and implications for early Earth’s atmosphere] may overturn fundamental assumptions about Earth’s early atmosphere.

The heart of the research was to create zircons in the laboratory, in essence making lava with various compositions and particularly with various levels of oxygen. The key to the research was using a rare earth metal, cerium, as a component of the zircon. Cerium is found in two oxidation states (containing different quantities of oxygen molecules). The more of the cerium with higher oxygen content found in zircon, the more likely the zircon was formed in magma with higher oxygen content. Since it is a long-standing hypothesis that most of Earth’s atmosphere was formed by outgassing from magma at the surface; demonstration that magmas of higher oxygen content would produce atmosphere with more oxygen could change long held beliefs about the early Earth atmosphere.

According to the Renssalaer researchers, Dustin Trail, E. Bruce Watson and Nicholas Tailby, zircon with the higher oxygen content was prevalent during the Hadean eon (4.7 – 3.8 billion years ago), and by their calculations this indicates that Earth’s atmosphere at the time contained more oxygen than previously thought. If it holds up under further testing, this is a significant finding that could change how astrobiologists view the conditions for the formation of life. Oxygen is a key component of organic material, and in the current notion of primordial atmosphere it was in short supply. It has long been assumed that the early atmosphere was mostly methane, carbon monoxide, hydrogen sulphide and ammonia – not the best mix for life. Now with the possibility that there was far more oxygen available in the crust of the Earth and in the atmosphere, the view on the formation of water and life could be pushed much closer to the origin of the Earth. As researcher Bruce Watson put it:

“Our planet is the stage on which all of life has played out,” Watson said. “We can’t even begin to talk about life on Earth until we know what that stage is. And oxygen conditions were vitally important because of how they affect the types of organic molecules that can be formed.”

Despite being the atmosphere that life currently breathes, lives, and thrives on, our current oxidized atmosphere is not currently understood to be a great starting point for life. Methane and its oxygen-poor counterparts have much more biologic potential to jump from inorganic compounds to life-supporting amino acids and DNA. As such, Watson thinks the discovery of his group may reinvigorate theories that perhaps those building blocks for life were not created on Earth, but delivered from elsewhere in the galaxy.

[Source: EurekAlert]

This sort of hypothesis will be controversial, but as is the case with novel but plausible research, it will be tested.

November 9, 2011: It was a reminder for the neighborhood (Earth and Moon) that strangers pass in the night. Night being metaphorical in this case because the asteroid 2005 YU55 actually took about three days to orbit through the vicinity of the Earth and Moon. As asteroids go, YU55 is fairly large, about 400 meters (1300 ft) wide, what Americans would call a city block. If it collided with Earth it would make a helluva bang, on the order of many megatons of TNT, roughly a nuclear bomb that would make a crater 6.4 km (4 miles) across and 518 meters (1700 ft) deep. Of course, it didn’t this time and probably won’t collide with the Earth in the future; so it serves as a reminder that such asteroids are around and collisions can happen. In fact, because 2005 YU55 also passes close to Venus and Mars during its long orbit, it is subject to gravitational and other forces that can alter its path. Current calculations indicate that despite changes caused by Mars or Venus, the asteroid still will not be anywhere near collision course with Earth when it comes back around 2041, however, there is a margin of error.

First seen in 2005 (hence the provisional name, 2005 YU55), this particular asteroid passes between the Earth and Moon with 319,000 kilometers (198,000 miles) to spare at its closest point to the Earth. It’s too far away and too small to be seen by the naked eye, but professional and amateur astronomers will have a day in the field spotting, tracking and studying the relatively infrequent event. The next such ‘near miss’ (to put it with as much dramatic spin as possible) will be in 2028 when asteroid 2001 WN5 swings by for a passing visit.

These passing asteroids, part of a group known as the Near Earth Asteroids are also the subject of a NASA mandate for a human landing. 2005 YU55 might, in fact, be a candidate. Asteroids present an interesting opportunity to ‘hitch a ride’ through the solar system, while at the same time extracting metals and minerals too heavy to be lifted in quantity from Earth. Since asteroids have negligible gravity, it would in theory be easier to ship heavy material from them than to fight the gravity well of any planet or moon.

It was, as so many jokingly put it, a real down-to-earth mission to Mars. As in, the mission never left Earth. Beginning June 3, 2010 and ending November 4, 2011, the Mars 500 mission took place in a facility at the Russian Academy of Science Institute of Biomedical Problems near Moscow, as a joint project of the European and Russian space agencies. Joking is easy but try looking at it this way: How would you like to step into a windowless room about as big as a studio apartment (12×66 ft or 3.6×20 m) and spend the next 520 days (18 months) with five other people, in this case all men, who until this experiment you’ve never met in your life?

Actually I’m not sure why this story was often treated by the media as something of a joke. Other than the obvious and unavoidable fiction of space travel while remaining on the ground, this was a serious experiment that cost over $15 million. The specially constructed facility, which included a simulated Mars Lander and an ‘external area’ that simulated the surface of Mars, was designed to maintain the isolation and confinement that would actually occur on a 500 day mission. The program included over 100 experiments, some requiring the use of spacesuits and there were many simulated ‘events’ that would typically be encountered by a real space flight. The six cosmonauts maintained communications with Earth, including with their families, but a transmission lag of up to 25 minutes was created, just as it would be on the 54 million kilometer flight.

It was not easy. In fact, all of the other attempts at doing something like this, including the expensive and widely hyped Biosphere II in Arizona (USA) were failures. Whether a mission to Mars was faked or you just put six people into a small space for a long time, the experience is grueling and potentially violent. It is already known that jealousy over workload and contact with loved ones was a problem among this crew.

It will be interesting to read what was learned from the experiment. We know that part of conquering the vast distances involved with interplanetary travel is overcoming boredom and the inevitable stresses of living in close quarters. Much has been learned from the navies of the world, especially those on submarine duty, but the situation in space – and especially the very long duration of travel in an unrelenting and extremely hostile environment – is different. How different, we have yet to learn. This experiment was part of the process of learning, for example, fatigue and lack of motivation were part of the difficulties encountered.

It is not accidental that the Russians spearheaded Mars 500. Almost from the beginning of the so-called ‘space race’ with the United States back in the 1950’s, the Russians placed greater emphasis on the human aspects than their counterparts at the U.S. space agency, NASA. This included, early on, extensive experiments and observation of psychological factors and later with social and cultural factors. Outside of weightlessness (microgravity) and the dangers of radiation in space, psychological and physical problems may be the most important in these long flights.

The six men who participated, three Russian, and one each Italian, French and Chinese were paid $100,000 for the duration. They also spent over a year in preparation. When they stepped out of the facility modules on November 4, they were pale but healthy. Officially, they said they were ready to go on the next mission. The next mission may well be even more ambitious – a similar experiment aboard the International Space Station, where microgravity is real.

The Global Warming controversy is ended. Right.

Take a look at the graph above. It shows the results of global temperature measurements over a span of some 100-200 years as compiled by four groups: NASA Goddard Institute for Space Studies, NOAA (National Oceanic and Atmospheric Administration), United Kingdom Meteorology Office Climatic Research Unit (hadCRU), and the Berkeley Earth Surface Temperature Project. Notice that the graph lines are almost identical and they all show a strong trend in global warming.

This is not exactly news, is it? No, but one line in the graph of particular interest is from a report that is making its way toward official release. It’s important because the data for that line on the graph is from those skeptical of scientific measurement of global warming. The Berkeley Earth Surface Temperature Project was begun by University of California physics professor Richard Muller, a man highly critical of the manner in which climate scientists were gathering and manipulating their data. Initial project funding included sources that generally contribute to climate change denial. Muller’ stated goal was to establish an independent source of climate data that would be thoroughly vetted for bias and error.

The Berkeley team, ten scientists led by Robert Rohde, a specialist in climatology with large data sets, included Saul Perlmutter, this year’s Nobelist in physics. The goal was to assemble a merged set of climate data from surface weather stations, check it for various errors, bias, or other distortions, analyze it with new and existing statistical methods, and provide public access to all the data and results. The result of the multi-year project is a database of 1.6 billion records of climate data, and a report that is now available at the website [Berkeley Earth Surface Temperature], which is heading for peer review and publication. Though not final, this is the official report.

The report is based on data collected from about 40,000 weather stations around the world. It will be difficult to impugn the source, as the Berkeley project explicitly stated that the quality of weather station reporting was sufficiently reliable and more importantly did not reflect the contention that modern ‘urban heat islands’ (the heat generated by cities and roads) affected a significant number of measurements. I would say that this data was also subjected to scrupulous statistical analysis, although that will have to wait for the peer review process to be validated. The essential results, in the words of Dr. Muller:

“Our biggest surprise was that the new results agreed so closely with the warming values published previously by other teams in the US and the UK,” said Professor Muller. “This confirms that these studies were done carefully and that potential biases identified by climate change sceptics did not seriously affect their conclusions.”

[Source: BBC News]

The findings of the Berkeley project agree that the global temperature has increased 1 degree Celsius since 1950 and the trend is up. In short, global warming is real.

So here we are in 2011, more than twenty years after the first warnings about the rise in global temperatures, and most people in the United States still think there is no global warming. The Republican Party has virtually enshrined climate change denial as part of its platform. At the same time, the U.S. military is planning for the effects of global warming on world politics and conflict. The energy industry is preparing a full-scale development of the Arctic petrochemical fields as the ice recedes, and plans are already in motion for shipping routes through the Arctic seas. Many countries, especially island states around the world, are making plans for rising coastal waters. This is what some like to call cognitive dissonance, the discrepancy between what people choose to believe and what is actually happening around them.

Will the addition of one more global warming report, albeit from a group inclined to be skeptics, have an impact? Watch your favorite media outlets. Will the results be highlighted? Will they be mentioned even once? Then judge for yourself.

Most western media have commented on the political (PR) aspects of this event. All such space efforts are political, in China or elsewhere. This project is interesting because of the contrast to the International Space Station (ISS), the decades-long effort by a consortium of countries. In this case China is following a resolutely go-it-alone approach. Although the program relies heavily on Russian space technology, there is nothing collaborative about it.

What’s more interesting is that the Chinese space effort is not being used in an organized way to flagellate the public into support for NASA or other western space agencies. There’s no Sputnik effect. Why?

One possibility is that experience with the ISS has taught NASA and others that until the problem of costly and dangerous transport between station and Earth surface is more than marginally improved, large permanent space facilities are not worth it. The amount and quality of research produced by the ISS is nowhere near what was expected. The Russians, in their blunt fashion, suggested that the ISS consortium let the $100 billion station fall into the ocean in 2020. So if the Chinese wish to build their own albatross for prestige purposes…let them have at it.

There is also speculation that the Chinese have military purposes in mind. However, space platforms such as the ISS are too public, too complicated and inconveniently multipurpose to be very appealing for the military. I wouldn’t rule it out, but it’s more likely the Chinese military will use specialized and highly secret satellites, just like the military elsewhere.

It’s most likely that the Chinese have chosen their space program to mark their national ascendency in science, technology and wealth. The U.S. and Soviet Union did that for a while, but the Russian economy collapsed and the Americans lost focus. Now we get to watch what the Chinese can do when faced with the same problems.

Earth has lots of liquid water, like oceans of it – though salty. Why would people be excited by briny water on Mars? However, for those intrepid, dreaming human beings who think of traveling to Mars and one day pitching camp there, the news from the NASA Mars Reconnaissance Orbiter (MRO) and reported in the journal Science [04 August 2011, paywalled, Seasonal flows on warm Martian slopes] is almost surprising: There may be, at times, running water on Mars.

Far and away most of the Martian planetary surface is too cold for water, liquid or frozen. With a mean temperature of -63 degrees Celsius, surface water or ice quickly sublimates in the cold dry atmosphere. It has long been thought, and then shown by satellite instruments, that water exists on Mars but only as subsurface ice. Now it looks like there may be exceptions.

Mars has seasons, much like Earth. It can get surprisingly warm at the height of summer in the middle latitudes, around 20 degrees Celsius (68F). It is there, in an area of the Southern hemisphere, where the MRO has taken a seasonal series of pictures of a slope with dark streaks, from .5 to 5 meters wide and hundreds of meters long, that appear with the Martian spring, grow bigger with the summer, and disappear with the coming of winter. There are several possible explanations (called hypotheses for scientists), for example the change could be caused by melting carbon dioxide; but the temperatures are too high to sustain CO2. At this point the one hypothesis that makes the most sense is liquid, salty water. Salty because the temperatures in the area during the ‘warm’ seasons are still too cold for pure water (it would freeze). However, the slopes where this occurs are struck directly by the summer sun and while the water may not be gushing, it is probably at or near the surface.

Probably. As with most science at this distance, the images and explanations are the best shot with the given evidence. That doesn’t mean it might not be something altogether different – a chemical reaction or the fluid motion of some other geologic material. In fact, there is already an interesting problem with the water hypothesis. The area of the flows was surveyed for the presence of water by the MRO’s Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) – none was found. This might mean the water is (mostly) subsurface. Then there is the dark color of the flows, which changes with the seasons. There are many possible explanations ranging from chemical reaction with water to the angle of light reflection. Such inconsistencies are the bread and butter of experimental science. The problem now goes to the laboratory where scientists will try to recreate the circumstances of the Martian flows. Someday, commitment to scientific budgets allowing, there may be direct sampling of the Martian soil and the mysteries will be resolved.

Meanwhile, there is provisional evidence of liquid water on Mars. This is not too surprising, really, given that by some estimates there are oceans of frozen water at or near the Martian polar caps. What may be causing the stir is that water in any form promises the possibility of life. This is especially true for liquid water, whether at the surface or deep underground in aquifers. The possibility of sustaining liquid water also increases the potential of Mars for human habitation – yes, the fabled Mars colonies.

Martian colonies are still very much science fiction. For now, science is doing its thing by following the water:

[SciTechStory: Mars water: What’s all the fuss?]
[SciTechStory: On the Moon or elsewhere, follow the water]

It’s been known for decades that there are striking differences between the surface of the Moon on the near side (the side we see from Earth), which is relatively smooth, low and flat, and the far side, which is high, mountainous and has a much thicker crust, about 50 kilometers (30 miles) thicker. It’s also widely accepted that something about the size of Mars slammed into the Earth about 4.5 billion years ago and ejected material that eventually coalesced into the Moon. The new hypothesis, as simulated by computer, proposes that two moons were created at about that time with the second roughly 1/30th (about 4%) the mass of the larger moon. The second moon shared the same orbit for about 100 million years but at some point it collided – not with a huge high velocity bang, but more likely a slower velocity “splat.”

The relatively slow impact caused neither a huge crater nor much volcanic activity, but added a deep layer of rock – a kind of mountain building from the sky – to one side of the Moon. Because of the Earth-Moon tides, the heavier, thicker side automatically became the dark-side, the one not visible from Earth. The model helps to explain the composition of the Moon’s crust, which on the near-side is dominated by potassium, rare-earth metals and phosphorus (the so-called KREEP composition). This could have been caused by displacement of ‘old crust’ from the far-side to the near-side during the collision.

Now here’s the key point: This is a model, which makes a hypothesis. It’s not the only model out there. In fact, Jutzi and Asphaug have colleagues at U.C. Santa Cruz that developed a model explaining the far-side geology as a result of the much stronger tides of the early Moon, when it was only about 80,000 miles from Earth. There are other models and other explanations, some of which have already been displaced by data returned from various Moon missions (e.g. the Moon is not made of green cheese).

The next step, as it is with any true scientific hypothesis, is to test it – to find evidence that confirms or disputes the conclusion. Data collected by NASA’s LRO (Lunar Reconnaissance Orbiter) may help, but the real kicker would be to collect rock samples from the far-side. Meanwhile, scientists will do what they usually do – argue – and try to knock down the two moon hypothesis, or replace it with a better one. Eventually, it is likely there will be enough evidence in this case to settle the argument, and science will move on. Splat, indeed.

Those things that can be said now, have been said, endlessly. I don’t pretend that among the few thoughts offered here there is anything new. It’s just that, like so many people, I grew up with the Apollo space program that put Man on the Moon, and the shuttle program that put up a permanent station in space. It seemed reasonable to believe that humans venturing into space were just part of the natural progress of the world.

Then over the years I learned something: Space exploration is roughly two-thirds politics. (I already knew there is nothing very natural about politics.)

It’s two-thirds politics because somebody has to pay for space exploration. Space exploration, especially manned space exploration is, to no surprise, very expensive. It is not only expensive but in all honesty with manned space exploration there is relatively little payback. It is so expensive and unprofitable that for the most part only governments have the money for it – if they have the money for it at all. That’s where the politics comes in. Space exploration from the beginning had to compete with other uses of government money. Typically a relatively large chunk was available for military space projects, almost all unmanned. This is not only true for the U.S. but also China and Russia. The non-military chunk of money depended on general budget allocations, which in turn depended on the political clout of the principle contractors that benefited from space exploration. This was and is a natural field for political sensitivity to economic conditions, bureaucratic infighting, and geopolitics.

I also came to realize that space exploration isn’t all about science and even less about advancing the story of mankind; except, of course, when it suits the narrative. That narrative is also for the most part political: The Soviets beat the Americans into orbit. It was a black eye for America. So America launches all-out man on the Moon project. Then the Soviets spend themselves into catastrophe trying to keep up. That’s a narrative. Occasionally the narrative is about the science, as for example the magnificent Cassini-Huygens space probes to the Saturn system. Manned space flight, however, was generally encased in a politicized narrative.

This leads to the snafu known as the American space shuttle program. I won’t repeat the history here, except to say that the shuttle program was an American project envisioned as an economical way to build and supply the International Space Station (ISS). It turned out to be adequate for building and supplying the space station, however it was anything but economical. It also blew up twice, killing people in dreadfully spectacular fashion. For those who defend the shuttle program, I have sympathy, but the fact is the shuttle program was ended years ago by the Bush administration because its thirty year old technology cost too much to operate. Now the ISS is supplied by rockets and other equally hoary, but cheaper, Soyuz technology of the Russians. This is such a rich irony considering the original political narrative.

For now human exploration of space is caught in the cracks between tight money in national budgets, the risk and cost of hurling people into space, the ambitious but nascent nationalism of the Chinese space program, and perhaps the desuetude of the world’s populations about space (it’s been boring for quite a while). What used to be front page drama (good and bad) is now part of the usual squabbling, small-beer routine of national politics – and not just in the United States.

With few exceptions, most nations have come to the conclusion that unmanned space exploration (robotic probes) does more for less. This has always been true and those nations constrained by finances and/or complex politics have eschewed manned projects for a long time. The exceptions have been the Russians for a while, the Americans, and the International Space Station, which though primarily American and Russian, has many participating countries, and now the Chinese.

The Chinese space program has focused on manned space flight almost exclusively. Publicly announced plans include a Chinese space station and a Chinese presence on the Moon. Whether the Chinese can accomplish this in the roughly twenty year time frame they announced is an open question. If they can do it, and so far it looks like they can, it may mean the rejuvenation of the ‘space race.’ Interestingly, however, their plans have so far failed to move the Americans, Europeans or Japanese toward any kind of counter-program. In some respects, the politics of space are obviously not what they used to be.

Meanwhile, private enterprise is getting into space, literally and figuratively. Notice, however, that the efforts are almost exclusively led by a club of people who formerly worked for the American space agency NASA or its contractors. Notice too that the companies run by these people are very small, barely equal to the payroll of a single NASA department. When big corporations get into the mix, then perhaps that will be a sign of potential profits. Until then, commercially it seems like a billionaire’s hobby club. That’s okay, but hard to believe it is leading any time soon to large numbers of people enjoying a vacation in space (or some such thing).

Until the day it becomes possible to ship bulk freight – including people – to and from space at rates within spitting distance of earthside shipping, the true habitation of space, even near-space, just isn’t going to happen. So far that technology eludes us. There is, in fact, a huge gulf between the grand projects (manned trips to Mars, a Moon settlement) and the ability to keep even the ISS usefully in orbit. I put it this way: The infrastructure for settlement and exploration of space is still on the ground, on Earth. Until a significant part of that infrastructure exists in space, outside Earth’s gravity well, the space adventure will continue to be hobbled by expense and unprofitability.

So I guess from my perspective, the final flight of the American shuttle program, while a symbol of almost catastrophically poor planning on the part of the Americans, is mostly indicative of a long transition period in the history of humanity in space. It will be a period – probably decades – where economics and domestic politics will usually trump grand accomplishments. Perhaps the Chinese can pull off something dramatic, but even the Chinese will need to find new technologies to make their achievements more than a one-off PR coup. The search for those technologies is likely to be something of a slog, hampered all the way by all the above mentioned economic and political factors. Yes, for those of us who grew up with the Apollo program and the promise of the International Space Station, this is a let-down. Let us hope that the unmanned scientific exploration of space continues to provide the few bright beacons of discovery that keep our interests up.

For the first time in perhaps two billion years the planet Mercury has a satellite. This moonless planet, which is itself smaller than many moons in the solar system and whose surface looks very much like Earth’s Moon, now has a tiny metallic canister in orbit around it, the Messenger space probe. Human science, engineering and money put it there, and it wasn’t easy. It’s a pity the achievement will be underappreciated.

Launch a rocket in Florida (USA) in 2004; lofting it through Earth’s atmosphere and send it on a trajectory consisting of a dozen enormous concentric orbits around the Sun covering 9.9 billion kilometers (6.2 billion miles) over 6 ½ years. Along the way fly by the Earth, Venus (twice), Mercury (three times), all the while chasing the orbit of Mercury and trying to use the planets and Sun to brake the Messenger spacecraft so that after a final burn of its main engines, it slips neatly into a complex elliptical (egg shaped) orbit around Mercury – close enough at one point to take good pictures (about 200 km/124 mi) but also far enough out (15,160 km/9,420 mi) at the other point to cool off.

All this Messenger completed March 17, 2011, and did it perfectly.

I think the achievement deserves a little ‘Huzzah!’ Not all space probes reach their destination and few had as lengthy a journey or were even remotely as complicated in trajectory. Oh, and of course, all the instruments, computers, and communications must work when it gets there.

Price tag: $446 million. Fortunately Messenger launched while the United States still had a taste for science and NASA still had a workable budget.

Thinking about that ‘taste for science,’ there are many people who wonder why so much money is spent on space exploration. This is kind of a cyclic question. It understandably surfaces in times of economic hardship (like now) and under certain political circumstances. The questioning occurs in all nations engaged in space exploration – the U.S., Europe, China, Japan, Russia, Brazil, India. There are many answers to the questioning, none of which is sufficient to end the controversies, because in the final analysis space exploration is a judgment on the way to use a country’s resources, and that’s a dynamic issue under constant change.

Some of the problem is created by the high visibility of space exploration; in effect, it can be the victim of its own success – or failure. In the western world far more money is spent on pet food than space exploration, but few pay any attention to the expenditure for pet food. Then too, this expenditure for space is at the moment mostly governmental – paid by taxes. This makes it more obvious, and in the minds of some, controversial – per se.

Why Mercury? It’s not just because it’s there, or just because we can. In the broadest terms, it’s because Mercury has many mysteries. It’s been photographed once, by the space probe Mariner 10 – but only 45% of the surface was covered. Mercury is difficult to study because it is so close to the Sun. It’s the smallest planet and the fastest moving. From Earth it’s seen only briefly at sunrise or sunset and usually enveloped in the glare of the Sun. Sensitive telescopes don’t even try to view Mercury for risk of burnout from sunlight.

Yet Mercury is a celestial ‘neighbor’ and a kindred planet. The Earth, Mars, Venus and Mercury are the ‘inner planets’ (nearest the Sun) and also the ‘rocky planets’ that have a metallic core and a mantle of ‘rocky’ (mostly silicate) material. As far as is known, Mercury is the oldest planet with an age of approximately 4.8 billion years. After Earth, it is the planet with the highest density – approximately 42% of its volume is the core and the core is composed mostly of iron and other metals. Consequently, Mercury has a magnetic field. These are all factoids about Mercury with some intrinsic interest, but for science the interest is how these came about. What is the geologic history of Mercury? Why is it so dense? What is the nature and origin of the magnetic field? It is believed that answering these questions will be important in piecing together theories on the formation of planets (rocky planets like Earth in particular). Now that rocky planets outside the solar system are regularly discovered, these theories will (finally) have real data for comparison.

Finally, there is the matter of water. Now that it is confirmed the Moon has substantial water and other ices preserved in the bottom of craters near the poles, it will not be surprising to find similar conditions on Mercury. The presence of ice was already suspected from radar imaging and Messenger should be able to confirm it. The presence of water on a planet so close to the Sun, and in fact in an area not subjected to the intense heat of direct sunshine, makes Mercury a potential location for human activity – mining operations, for example – however far off that seems now. Tourist packages to the planet Mercury might be a tough sell.

Tourism aside, the knowledge gained by studying Mercury presents a great challenge – piecing together the history of our solar system and by extrapolation the possible history of countless other solar systems we may observe elsewhere in the universe. It’s part of a massive intellectual feedback system where solving problems and gaining insight leads to asking more questions and more insight. Some of this has immediate practical impact, much of it has potential for the future – and some of it becomes trivial or superseded. On balance, what it does is keep mankind curious, thinking, and learning. This is arguably worth a tiny bit of a nation’s wealth.