In our tour of the solar system, we should start by exploring the innermost planet. A brief distance from the inferno of the sun we find it, hurtling through space at 40 to 60 km per second in its 88 day cycle around the sun. It also is heavily cratered, with no air (or just a hint of one) to secure its surface or erode indications of previous collisions. The sun as seen from this distance is approximately twice as big as from Earth, and we know this will be the most dominant force affecting our trip for this planet.
Now we’ve touched down and we have a fast look around. Looking up in the sky we see a black, star-speckled skies dominated by the fiery world of sunlight almost 3 times bigger than we are knowledgeable about. There’s only the faintest hint of an air, and the only way we know it’s there’s the instrumentation we have with us. It’ll be completely useless to us. If we had been on the night side the temperature would fall to -270 degrees. We would never live here without space suits.
Bending down to inspect the surface we find a layer of dust like what astronauts found on the moon. This is the result of centuries of meteor impacts, as well as the extreme temperature differentials implemented from a hellishly near sun. The procedures which shaped this world across the eons were substantially different than those that shaped our home world.
Around us are the pockmarks of craters, some mountain ranges, and a horizon considerably closer than that which we know at home.
Unlike what astronomers once thought, there’s truly a cycle of times here, but it’s much different than anything we’re accustomed to. Mercury isn’t tidally locked with sunlight, but tidal forces have slowed it to the point where its day is 58 of our times (really it will one day many years from now become locked one facet to its enormous neighbor). This results in some rather peculiar observations when we were to stay that long. In certain areas on this world we would then see the sun slow and really backtrack a brief distance before continuing its slow march across the sky.
We take one more look around the globe. No, Mercury isn’t an enticing place for people to go to. Maybe one day we’ll have reason to be here, possibly for the rich deposits of iron and other metals or for observational purposes, but this isn’t the day.
Mercury has been know and observed at least since the days of the Sumerians from the 3rd century BC. After the Sumerians there’s better documentation in the Babylonian Empire. Records in the 7th century BC refer back to much earlier documents which described observations of Earth. The Babylonians called the world Nebu, after the messenger of the gods in their mythology. This is a fascinating parallel to the Greek mythology and reference to the innermost planet. The ancient Greeks had two names for the entire world, Apollo observable in the morning and Hermes observable in the evening. They finally came to understand that these were exactly the identical object, and it was even suggested that this early in history that Mercury and Venus orbited the sun.
Early modern astronomy started making observations of Mercury from the early 17th century when Galileo turned into an early telescope into the inner world. A sketchy vision of this planet developed from there, but its proximity to the sun has always made this one of the most troublesome members of our solar system to study. It has only been lately with the arrival of new imaging methods that ground-based monitoring has drastically improved.
And what of study with space probes? This is also laced with technical issues. An application of Newton’s Laws of Motion demonstrates that it requires more rocket fuel to reach an orbit around Mercury than necessary to escape the solar system. Due to this just one spacecraft has visited the world thus far, the Mariner 10. After its analysis of Venus, the probe made three flybys of Mercury in 1974 and 1975 as it mapped about 45 percent of the world’s surface. The Mariner 10 circles the sun in its lone orbit round the sun to this day, although its digital devices have long since been destroyed by the sun’s intense radiation.
Our toughest Mercury research project to date was started August 3,2004 with the launch of the Messenger by NASA from Cape Canaveral. It’s carrying high resolution imaging apparatus, spectrometers to ascertain the composition of the crust, and magnetometers to study charged particles around Earth. After every couple of centuries there’s an occultation of Mercury and Venus. This happens when Venus really passes directly in front of Mercury for a couple of minutes. The last one occurred on May 28,1737 and another will occur in 2133.
Much of Mercury’s mass consists of an iron rich core. Recent theories indicate that this core comprises the majority of the 4879 mile diameter of Earth. Due to Mercury’s slow rotation period, there’s hardly any tectonic or volcanic action.
There have been a number of theories introduced to explain why Mercury is so metal rich, and why its core features such a massive area of the world’s structure. One popular theory is that the world was struck by a huge body early in its history and dropped most of its outer,”lighter”, mantle. Another theory is that the intense heat of the ancient sun vaporized the outer portion of Earth, providing the young Mercury a dense atmosphere of gaseous stone, which was carried away by the massive solar winds of a far more volatile sun. The competing theories to explain the unusually heavy makeup of Mercury will be analyzed by the approaching Messenger mission.
The Future of Mercury and Its Potential Role in Their Future
Mercury’s most dominant feature makes it an attractive part of our future: its enormous stores of heavy metals, particularly iron. Though its proximity to the sun makes it tough to envision humans living and working there, I could envision automated factories mining its own surface and freighters picking up the ore to bring it back for our use.
Mercury will stay pretty much as it’s for centuries to come. As the sun slowly increases in intensity during the next 4 to 5 billion years, the planet’s surface temperature will gradually rise with it. Then a singular moment will arrive as the whole solar system varies with the start of the sun’s passing into its next stage. After the sun consumes a vital amount of its hydrogen gas it will, within a matter of only a couple days, enter its red giant stage.
At the point Mercury will be the first of the inner planets to be completely absorbed.