Assignment 3 Essay Example | Topics and Well Written Essays - 250 words - 2

Assignment 3 - Essay Example Scientists describe dark energy as a form of energy in space that accelerates the expansion of the universe. Evidence of dark energy is through: the supernovae, large-scale structure theory, observational Hubble constant data, late-time integrated Sachs-Wolfe effect and the measurement of the cosmic microwave background (Sarkar, pg33). The proponents of the top down scenario proposed that the structure forms through the collapse of a huge gas cloud and as the cloud collapses the gas forms a rapidly rotating disk which is the galaxy (Sarkar, pg55). The bottom-up scenario, on the other hand, involves the merging of smaller objects to form large ones, which mean that galaxies form by the coalescence of smaller structures to form one huge structure. The age of the earth and formation of the various specular objects is the point of contention among the scientists for many centuries. However, there are features and theories which strongly suggest that the earth is at least a million years old: One of the theories tested is the calculation of the rate at which the salt is delivered to the ocean. The level of salt in river water is small and since most rivers flow into oceans measuring the evaporative concentration of the salts reveals that the age of the earth is more than a million years. The thickness of total sedimentary record divided by the average sedimentation rates also yields the same conclusion that the earth is more than a million years