Astronomy and short essay questions

¶ … English system of measurement is so complicated to some people is that it has a different basis for different measurements. For most things, the metric system is used and is based on powers of 10, in other words decimalized. This has been the preferred European and scientific method of measuring since the late 1700s, and is not part of a standard system known as the International System of Units. In general, since the metric system is based on decimalized, or powers of 10, then units based on 10s would be more aligned in math, this might be conceptualized in the different between the need for 2 calculations versus 1: If George needed a desk that was 5 ' X 4' feet wide, how many inches of trim would he need for the whole desk. Trim is measured in metric units, let's say, not inches or feet. So the calculation would be 5 X 4 = 20 feet perimeter for the trim, there are 12 inches per foot, so 20 X 12 = 240 inches, then converted to metric, etc. -- resulting in two, rather than one, calculation. (Source: Kerrod, Baker and Atkinson, (1991). Weights and Measures. Marshall Cavendish.

Part 1-B -- Some units are measured differently in order to make their meaning more concise or easier to conceptualize. For instance, we can measure the Earth to the Moon as 240,000 miles, or 94 million miles from the Earth to the Sun; conceptually we understand these terms. As distances in space increase, though, there would be too many zeros; trillion and trillion miles, etc. so distances can be measured in AU (Astronomical units) which use the Earth to Sun ratio, 1:1; meaning in AU Venus is .72 AU. Conversely, when distances become even vaster it is more understandable to measure in light-years; the time it takes light to travel in a year, about 5.8 trillion miles or 9 trillion kilometers. The nearest start to us is Alpha Centauri, is 4.3 light years, easier to conceive than 5.8 X 4. 3 = 247.4 trillion miles. (Source: http://www.sky-watch.com/articles/howfar.html).

Par 2-a -- Apparent magnitude is a measure of brightness as seen by someone observing from earth. The brighter the object, the lower its magnitude. Absolute magnitude corrects from the observer and measures an intrinsic brightness. The absolute magnitude equals the apparent magnitude as if were a standard luminosity distance (10 parsecs or 1 AU) depending on the type of object. (Source: http://www.astro-tom.com/technical_data/magnitude_scale.htm).

Part 2-B -- Happarchus was a Greek astronomer who viewed the stars and classified them by his version of brightness (bright was Magnitude 1, etc.) down to Magnitude 6, stars he could barely see. Modern astronomy, using higher levels of math and measuring technologies, realized that this is a perception and does not really correspond well to how bright stars area -- the human eye adjusts and makes judgments. Thus, modern astronomers use a scale and ratio of brightness to be more precise, regardless of the observer. (Source: http://curious.astro.cornell.edu/question.php?number=569).

Part 3-a -- Both the Copernican and Ptolemaic models of the cosmos were based on the best available data for the time; Ptolemy in the Ancient World, Copernicus in the 2nd century. Ptolemy saw the earth as the center of the universe, Copernicus the Sun. This also became part of a debate that was both scientific and philosophical -- heliocentrism implies more metaphysical implications about God being the center of the universe as opposed to man (earth). Circular orbing is the same, and Ptolemy required uniform speeds. (Source: http://www.soaziglebihan.org/docs/PHIL2402008F/2008-PHIL240-7.pdf).

Part 3-B -- Tycho Brahe was a Danish astronomer living 1546-1601. He is best known for a more accurate and comprehensive way of observing the universe, and refuting the theory of the celestial spheres by showing Ptolemy was wrong about believing space was unchanging and flowing around the earth. Tycho;'s model had the Earth stationary, the Sun going around the Earth, and the planets going around the Sun. (Source: http://www.phy.duke.edu/courses/055/syllabus/lecture9.pdf)

Part 4 -- Newton's law of universal gravitation clarified the heliocentric universe by finding mathematical proof as to the motions of the planets and their relative positions -- the idea of movement in a measurable rate or elliptical orbits and the attraction bodies seemed to have for one another (earth-moon, etc.). If we use Kepler's 2nd Law "A line joining a planet and the Sun sweeps out equal areas during equal intervals of time," and Third Law "The square of the orbital period of a planet is directly promotional to the cube of the semi-major area of its orbit," we can mathematically map out circular motion for planets and moon revolving around other bodies. (Source: http://csep10.phys.utk.edu/astr161/lect/history/newtongrav.html).

Assignment 2-1 -- a- Radiation may be considered information from space; different types of information from different sources. These are: 1) Light as a wave and particle, 2) Electromagnetism, 3) Cosmic Rays and 4) Ultraviolet radiation.

Part 2-1-B- Light may be measured by telescopes; other space radiation by radio waves; x-ray machines may absorb cosmic and x-ray energy.

Part 2-1-C- Stars and Planets emit electromagnetic; Sun emits UV, Electromagnetic and light; light intensity, etc. Measuring radiation from objects tells us numerous things; age of object, comparative data between object, distance, intensity, level of danger, potential changes within object over time.

Part 2-1-D- Spectrographs, radio frequency detectors, x-ray machines.

Part 2-2-a -- an atom is the smallest unit of matter; ions are types of atoms in which the protons and electrons (parts of the atomic structure) are not equal. Ions can exist independently in solution, while atoms may or may not be able to -- even though atoms are the smallest particle of an element that can have a chemical reaction. The ion makes up the electric charge (positive or negative) of an atom.

Part 2-2-B -- an atom may be excited if it hits (collides) with another atom or electronic; or if it absorbs a proton. This excitement may be thought of as a higher level of energy.

Part 2-2-C- Hotter materials have faster moving atoms, thus causing the heat to be generated. The Wien Law explains the way in which all heated object emit a measured spectrum of waves, and the beak shifts to shorter wavelengths as the temperature rises.

Part 2-2-D -- a continuous spectrum is a chart of colors from red to ultraviolet; light emitted by gas in which there is an electrical charge is a bright line spectrum; dark line, or absorption spectrum is due to absorption of light by cool cases. Examples 2-3 below are all of hydrogen:

Full/Continuous Spectrum:

Bright line Spectrum (Hydrogen):

Dark line/Absorption Spectrum (Hydrogen):

Part 3 -- Spectral classification is a way of describing starts based on the ionization of it chromosphere (what atomic exitors are more abundant in the light, giving it a characteristic hue). It is related to the Balmer Series in that Balmer is calculated using a formula that designates spectra from hydrogen.