Astronomy 123 Homework - Assignment Example

Assignment Question When massive stars explode, they leave remnants, which are a few times, the mass of the sun. Large fractions of the materials resulting from the explosion are thrown outward at massive speeds. As the material sweeps through the surrounding gas, heat and shock radiate which leads to the production of arcs and rings seen in the pictures. The high energy, which went into the explosion, leads to the production of a supernova remnant. The initial expanding shell contains the outer parts of the exploding star, which move at high speeds of approximately 2000 to 10000km s-1 (Yockey and Hubert 112).

The shell becomes more massive as it sweeps the surrounding, it, therefore, slows down. The remnants of these explosions can live up to100,000 years, which seems a long duration in terms of astronomical time scale. The most recent supernova experienced in our galaxy was discovered through tracking the remains of its massive explosions. NASA uses Chandra X-ray observation to estimate the frequency with which supernovas explode in the Milky Way Galaxy. NASA estimates that the last supernova occurred almost 140 years ago measured within the period of the earth.

Initially, the last supernova had occurred in 1680. Supernovas are, therefore, rare occurrences with only six observed in the earth’s galaxy over a period of 1000 years (Yockey and Hubert 142). The estimate for their occurrence is one supernova for every 25 to 100 years; therefore, it is likely that one may occur soon.Question 2 The first theory explaining the origin of water talks about volcanic activity. It suggests that when the earth cooled, certain elements that broke apart recombined forming new substances.

Two of those elements are hydrogen that broke away from hydrocarbons (for example methane) and oxygen that broke away from iron oxide. Molten magma carried these elements to the surface; they then combined to form water. This however does not seem sufficient to account for 70% of the earth’s surface. Another theory suggests that water was delivered to earth by earth-grazing comets. While the nebulae has water within its remote corners, analysis of this water shows that it is not the same water like that found in the earth’s oceans.

Question 3 The snowball earth hypothesis states that the surfaces of the earth and the ocean were covered with ice across the poles of the equator during periods of extreme cooling about 2.4 billion years ago (Singh 109). Evidence for this hypothesis is found in the ancient rocks that preserve signs of past magnetic field. Additionally, there is a thick layer of manganese ore discovered in the Kalahari dessert. Scientists suggest that its deposition is a result of massive and rapid changes in the global climate as the ice that covered the earth melted.

Question 4 Europa is one of the major moons in Jupiter. It is the only moon or planet in the solar system that has liquid water. A Hubble space telescope detected the presence of a thin layer of oxygen in its atmosphere. Moreover, there is an absence of craters caused by meteorite impacts; this is a sign that indicates active geology (Singh 109). The islands in Europa that are of thicker ice are similar to the polar caps of the earth.Question 5 Scientists argue that hydrogen led to saturation of alkaline water.

Getting in contact with acidic water in the ocean vents can lead to the production of natural proton gradients in the mineral walls. Such a setup creates the right conditions that lead to conversion of hydrogen and carbon dioxide into molecules that contain organic elements. These elements form the building blocks for amino acids found in life.Works CitedSingh, G. Earth science today. New Delhi: Discovery Publ. House, 2009. Print.Yockey, Hubert P. Information theory, evolution, and the origin of life.

Cambridge New York: Cambridge University Press, 2005. Print.