A S T R O N O M Y 1 1 0
Chapter 1 Chapter 2
Chapter 3 Chapter 4 Chapter 5 Chapter 6
Getting Your Bearings, The Sizes of Things Math Review The Constellations Constellation List Star Maps Star Songs How Earth and Sky Work- Effects of Latitude How Earth and Sky Work -The Effect of Time Positions of the Sun, Moon, and Planets Eclipse Tables and Map History of Astronomy -Ancient Times through Galileo History Timeline Calendars and Time The Start of Modern Physics Using Equations and Formulae Illuminating Light Solar System Overview
Chapter 8 Chapter 9
Chapter 10 Earth, Our Point of Reference History of Earth Chapter 11 Comparative Planetology Test 1 Review Test 2 Review Final Review
THE VISIBLE UNIVERSE 2013
karen g castle
Chapter I Getting Your Bearings, Math Skills and The Sizes of Things Finding sizes: As part of our introduction to astronomy, you will be finding sizes of things and plotting the items. Part of the point is to get an idea of what is in the Universe. Part is to use scientific notation, review conversions and use the proper number of significant figures and use a logarithmic plot. You might need to find mass or radius or lifetime. The assignment is geared to Pathways to Astronomy, but you may use the internet to find the information. Be very careful to get what is requested. Download and save the Internet reference if you want to be able to show that the answer is correct. When using the book’s index to find information, be sure to read all the words and to look on each page. You might find values that differ from other people’s. For some objects, like the size of the Local Group, there is no firm outside edge and measurements of the size are all the same from one researcher to another. This does not mean that one value is right and the other is wrong. Converting Units: We compare features objects in order to get a concept of the Universe. The term size is somewhat vague. It might mean mass, radius, area, circumference. None of these is directly comparable to another. So we need to compare consistent measurements. Even when we have comparable measurements e.g. lengths for everything, the values all need to be in the same units so that we can understand what is larger. What if we don’t have the information in the same units? It is necessary to convert them to the same units. For example, you might be seeking the size of an automobile. Possible answers would be the length of 0 a Mini Cooper, about 143 inches long (3.61x10 meters in scientific notation) and 55.4 inches (1.47 0 0 x10 meters) high. A Lincoln Navigator might be 5.3x10 meters long and about 1.98 meters high. We converted the lengths or heights of the vehicles to the same units to see which is larger. On the other hand, the mass of the auto, or the surface area are different from one another and different from the length or height. They cannot be compared directly.
Units- In science (and almost everywhere but the USA) use the metric system. So lengths should be in centimeters, meters, or kilometers. Time is usually in seconds. Mass would be in grams or kilograms. In astronomy there are some other unique units. These include Astronomical Unit – distance between Earth and Sun 8 11 1AU=1.496x10 km=1.496x10 m Light Year(ly), distance light travels in a year Parsec(pc) is the distance of a object whose parallax is 1 second of arc 1pc= 3.26 light years 1 pc= 206265 AU 13 1pc =3.0856x10 km 16 1pc =3.0856x10 m 3 1kpc=10 pc 6 1Mpc=10 pc 3 10 millimeter (mm)=1 meter 100 centimeters (cm)=1 meters (m 3 10 meters (m) = 1 kilometers (km) 1 mile (mi)= 1.609 km 1 mile=5280 feet 1 meter = 39.37 inches 1 inch = 0.0254 m (beware, meter is abbreviated m and mile is abbreviated mi) 1 foot = 12 inches Converting Units Converting units does not change their meaning. But, as you know from algebra class, the only things that can be done to a number without changing its value are to add 0 or to multiply by 1. To convert...
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