Observation 1.3: Astronomy Cast Ep. 220 (Mass Extinctions)

This episode talked about mass extinction events, and the various extinction events that have occurred throughout the history of our planet. There have been five of these, the most well known being the Cretaceous-Tertiary extinction event. Known also as the KT event, this extinction led to the death of the dinosaurs, and was most probably caused by a large asteroid impact. Particularly interesting is the idea presented in the podcast that we are currently experiencing a sixth great extinction, as a result of human influences on the planet. 

Observation 1.2

This observation took place in my back yard, using a family telescope, on the 23 of October, between 7:30 and 9:30 PM. On this night the sky was clear, and I was able to make out many objects. Notably, I could see a bright Jupiter, as well as the constellation Scutum.

Observation 1.1: Astronomy Cast Ep. 227 (Big Dipper)

This episode of the Astronomy Cast talked about the Big Dipper. The Big Dipper is the common name of the constellation Ursa Major, and is one of the most well known constellations in the sky. The Big Dipper has long been used to as a guide north, due to the brightness of it's stars. This has helped many people, including runaway slaves and sailors. The Big Dipper is known by other names depending on the culture of the area; in Europe, for example, it is known as The Plow.

APOD 1.7

This is a mosaic image of the planet Murcury, the closest planet to the sun, taken by the MESSENGER spacecraft. The MESSENGER is the first spacecraft to orbit the sun, and captured these images in 2008 and 2009. An intriguing fact about Mercury is that, on the planet, a solar day is about twice as long as a solar year, due to the unique orbit of Mercury.

Gian Cassini Biography

Gian Cassini was an important astronomer of the seventeenth and eighteenth centuries, and made many lasting contributions to the development of modern astronomy. Born in 1625 in France, Cassini studied mathematics, engineering, astronomy, and astrology, but worked primarily through his life in astronomy and astrology. Cassini’s interest in these areas was apparent from an early age, as he studied at a Jesuit college in Genoa and an abbey in San Fructuoso. Cassini’s skill and interest in the heavens attracted the patronage of many supporters, who financed his work or taught him valuable skills. Among them were the astronomer and senator Marquis Cornelio Malvasia, who later encouraged the senate of Bologna to commission Cassini to take a year long trip to Paris, France, to help construct the Paris Observatory.  Cassini, however, opted not to return, and stayed in France until his death in 1712. During this time he met and married his wife, Genevieve de Laistre, who granted him an impressive dowry of valuable land, and came to be known as Jean Dominique Cassini. Cassini also made many of his greatest achievements while in France, which surprisingly often had nothing to do with astronomy or astrology. Notably, he conducted negotiations between Bologna and Ferrara over control of the Po River, created memoirs on flooding and avoiding it, and conducted hydraulics experiments.

Cassini’s expertise also led him to make many breakthroughs in engineering and astronomy. He used triangulation to create the first topographic map of France, revealing it to be smaller than previously thought. He made a great number of observations regarding Saturn, including discovering four of Saturn’s moons and their lengths of rotation, discovering Spots and bands on the planet, and finding a new segment of rings, later named the Cassini Division after  him. Cassini devised a series of laws, known as Cassini’s Laws, which describe the motion of the moon. While these laws were not perfectly accurate, they were significant in their time and have since been adjusted to describe other satellites, and even planets. Perhaps most notably, Cassini, along with fellow astronomers, made great strides in mapping the distances of the universe by estimating the Astronomical Unit. This was done by sending a fellow astronomer to French Guyana and taking simultaneous observations of Mars from the two different locations, using this data to determine the distance between Mars and Earth. Although relative distances had already been found, the acquisition of exact values allowed for precise distances to be calculated as never before.

Cassini’s legacy has lived on to the present day, and continues to influence modern astronomy. Starting from a young age, Cassini devoted much of his life to understanding the universe, stopping only when afflicted by blindness before his death. Much of his work was continued by his son and grandson, who themselves became notable astronomers. His name lives on in the Cassini satellite, launched to investigate Saturn.

APOD 1.6

This is an image of the destruction caused when a lerge meteor impacted the Tunguska River in Siberia. Thought to be the most powerful natural explosion in recent times, this impact of this meteor had 1000 times the force of early atomic bombs. Although the article reports that an impace with a city is unlikely, the threat of future meteor collisions is a very concerning prospect.