As I was looking at another students post about terra-forming Mars, I was inspired to do a little digging about the possibility of artificially creating an atmosphere for the Red Planet. Mars currently does not have a strong magnetosphere, meaning that whatever atmosphere would normally be found around the planet is extremely vulnerable to solar winds. One suggestion to circumvent this problem would be to build a small magnetic field for Mars, so that other terra-forming operations could proceed.
This article discusses a NASA proposition to do exactly that. The project would place a large man-made shield to deflect solar wind which would normally deplete the planet’s atmosphere. The article suggests that theoretically, this device would allow Mars’ surface temperature to rise by about 4 degrees Celsius, which may be enough to free enough of the carbon dioxide held in polar ice caps to thicken the atmosphere. The thicker atmosphere would then begin the greenhouse effect, which would heat the surface even further, potentially making life more sustainable on Mars.
On Earth we have a variety of geological features which arise due to tectonic activity on the planet’s surface. These features include mountain ranges and deep sea trenches, but tectonic activity is also responsible for earthquakes and some volcanic activity. For quite some time, it was believed that Earth was the only place in our solar system that experienced this type of activity. However, new research has provided evidence that Mars may be in the very early stages of tectonic activity. This article tells how scientists have found evidence of fault lines (like those found in California) from satellite images and the lead researcher, An Yin has suggested the possibility of seismic activity, or “Marsquakes.” One last thing that I found interesting in this piece is that Mars seems to have fewer tectonic plates than the Earth. This is partially due to the smaller total surface area, but Yin suggests that it may also have to do with Mars’ relatively inactive core. Because Mars’ center is cooler and not experiencing the same currents as Earth’s mantle, there is less force acting upon the surface plates.
We’ve all heard that Stonehenge was a type of calendar or observatory that has been around longer than civilization. I did some digging to find other examples of ancient astronomy practices and I came across the following video:
This is an example of ancient people demonstrating an understanding of astronomy much before the first civilizations began. This structure, like Stonehenge has sight lines oriented toward the sunrise and set locations during a solstice. More interestingly, outlying monoliths marked the location or sight line where particular stars from the constellation Orion were to make their vernal equinox heliacal rising (where the star rises with the sun on the first day of spring). This is a very rare event for a particular star, and occurs once every 26,000 years and represents a restarting of the star’s precession timeline.
Even more interestingly, the distance of these monoliths from the central observers location accurately represents the true distance to each of these stars. This structure was created 6,000-8,000 years ago, and to fathom how these people could accurately know, measure, and represent these distances is absolutely mind-boggling.
Isaac Newton had several major discoveries or influences on the field of astronomy. First, he developed a theory to describe motion in the universe, gravity, and has three laws of motion named after him. Secondly, and perhaps more important to the field of astronomical observation, rather than theory, Newton’s work in optics allowed him to invent the reflecting telescope using mirrors, which provided better quality than the refracting telescopes which used lenses. (source)
Historical Events contemporary with Isaac Newton:
Glorious Revolution (England). A revolution in England surrounding the issues of religious tolerance and unjust taxation lead to the overthrow of James II, which placed William III on the throne. The reforms that accompanied this rebellion gave Parliament greater power over taxation, crown expenditures, as well as succession. This development paved the way for later uprisings and changes of government, such as the American and French Revolutions. (source)
War of Spanish Succession (Europe). In 1700, the last Hapsburg king of Spain dies without a direct heir. The ensuing squabbling over the crown lead to land war in Europe and a shifting balance of power between the colonial empires. This has implications for Europe throughout the 18th century, but also for parts of the New World. (source)
Benjamin Franklin (17 Jan 1706 – 17 Apr 1790) (21 year overlap with Newton). Franklin was an important figure in early American history, contributing much to the new nation through his contribution to the continental congress and his position as the first postmaster general. Franklin had great ties to France, which of course became America’s greatest ally during the war of independence. (source)
Part of what is very interesting to me about history is the notion that so many things that we would normally study separate from one another, occur all around the same time. Studying Newton and other contemporary events shows the complexity of world history. One would normally not consider Newton and Cromwell related, yet the lived at the same time. Their contributions to history and society were very different, yet they were countrymen.
As we all know, the Earth experiences seasons each year. These are due to the tilt of Earth’s rotational axis, which causes certain areas of the earth to receive more direct sunlight during parts of the year, which has obvious effects on yearly climate.
Interestingly, the Earth’s seasons also shift around on the calendar year. Eventually, summer in the Northern Hemisphere will take place during December and January and the winter solstice will take place in July. This phenomenon is known as the Milankovitch Cycle.
Over a long period of time the Earth’s eccentric orbit around the Sun changes orientation due in part to the Apsidal precession of the Earth. In a normal orbit, the Earth is closest to the Sun during January but over time this will change. When the Earth is closer to the Sun, it receives a larger amount solar radiation. This small difference in solar radiation the Earth receives at the closest and furthest points creates a slight change in overall climate patterns. In a single year, this change is not terribly noticeable, but over the scale of 100,000 years, the changes in climate become more significant.
So what does solar radiation have to do with the Milankovitch cycle? As Earth’s eccentric orbit changes its orientation, different parts of the Earth receive the more direct solar radiation. This matters because it has a huge long term effect on global climate processes such as glaciation. Understanding that the position of Earth’s tilt will change over time can lead scientists to study periods of Earth’s history (such as the Ice Ages) in a different light, or make predictions about the long term climate future of the planet.