Earth Science / Astronomy Ptolemy Essay

The Moon is believed by many to have been part of the earth and that it was tore off as a result of an initial spin that was too great to hold the planet together. One of the prevailing theories was that involving an impact of large magnitude involving the newly formed Earth and a giant object of the size of Mars hitting Earth and blowing up material that later formed the moon.

Q7. Astronomers mainly use the Hubble galaxy classification system when trying to recognize a particular galaxy as belonging to a particular type. The system was created by Edwin Hubble in the twentieth century, as the American Astronomer came up with three groups through which one could classify any galaxy in the universe. Elliptical galaxies look like ellipses, light being distributed evenly. Spiral galaxies are similar to Elliptical galaxies, but they differ through the fact that they are composed from a flat disk, with stars composing a structure similar to a spiral and involve a middle concentration of stars, which makes this type of galaxy look like an elliptical galaxy in its center. Lenticular galaxies resemble spiral galaxies to a large degree, but they differ through the fact that they do not look like a spiral and their disks from a limited quantity of stars.

Q8. A star's life cycle contains the following steps: protostar formation, main sequence, and post-main sequence. Stars are initially formed into a high concentration Nebula; they later condense in large spheres of gas and decrease because of their own gravity. Parts of condensed matter heat up and create protostars. The energy released by the celestial object causes it to stop contracting more energy and it begins to shine as a result, becoming a main sequence star. The main sequence lasts for approximately ten billion years, the period it takes for all the hydrogen to fuse and form helium. The helium later fuses and forms carbon and light gradually loses intensity, turning into an expanding star called the Red Giant.When the helium runs out the core is about 80% from the star's original size cools and loses intensity, becoming first a White Dwarf and later when it seizes to shine becoming a Black Dwarf. In the case of a Massive Star, the stars become Red Supergiants the moment the hydrogen ends, causing nuclear reactions to take place for the following three million years. The Massive star's core then collapses, causing an explosion also known as a Supernova, blowing shock waves through its surface.

Q9. Terms like dwarf and giant stand as classification to note the differences in spectral lines on a HR diagram, indicating if a particular star is on the main sequence or this step in its life cycle has been completed. White dwarfs are the final phase in the evolution of a star that did not have enough mass to supernova.

Q10. Most astronomers agree to the principles put across by the Big Bang Theory, which claims that the universe was originally in a hot and solid state and that it is currently cooling down and expanding. Cosmic microwave background radiation is electromagnetic radiation present in the universe. After discovering this form of radiation a great deal of scientists became certain that the Big Bang theory is very probable.

Works cited:

1. Coles, Peter and Lucchin, Francesco, Cosmology: The Origin and Evolution of Cosmic Structure, 2nd ed. (Chichester, England: John Wiley & Sons, 2002)

2. Mcfadden, Lucy-Ann; Weissman, Paul R. And Johnson, Torrence V. eds., Encyclopedia of the Solar System, 2nd ed. (Boston: Academic Press, 2007).

3. Wilson, Robert, Astronomy through the Ages: The Story of the Human Attempt to Understand the Universe (London: Taylor & Francis, 1997)

Wilson, Robert, Astronomy through the Ages: The Story of the Human Attempt to Understand the Universe (London: Taylor & Francis, 1997) 36.

Idem

Peter Coles, and Francesco Lucchin, Cosmology: The Origin….....