I was reviewing a MAT082 lecture note and I clicked the Astronomy Picture Of The Day hyperlink. The "Explanation" for the picture started as follows."A cosmic bubble of gas and dust, RCW 79 has grown to about 70 light-years in diameter."
Diameters... timely subject; therefore, let's look at NASA.gov:: RCW79.
Google.com:: define: light-year
A light-year approximates
5.88 trillion(5,880,000,000,000) miles. This number needs to be multiplied by
70because the RCW79 cosmic bubble is
70 light-yearsin diameter. [Note: the
880 billion.]5.88 x 70 = 411.60 70 light-years is 411.60 trillion miles. 411.60 trillion is 411,600,000,000,000 411,600,000,000,000 is 411.6 x 1012 411.6 x 1012 is 411.6 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 x 10 411.6 x 1012 is 4.116 x 1014
First returned Google hyperlink was to The Nine Planets Glossary at Arizona.edu.
A light-year is "the distance light travels in one year." The speed of light approximates
186,282 miles per second. One light-year is
63,239 AU, where AU is astronical unit (distance between earth and sun).
Wikipedia.org:: Speed of light
Creator: Gerald D. Thurman
Created: 15 April 2005
This work is licensed under a Creative Commons License.
One of the definitions given by Google said a light-year was "approximately 5.8 trillion miles." The difference between 5.88 trillion and 5.8 trillion is
.08 trillionwhich is
In some cases being off by plus-or-minus
80 billionis insignificant; however, in other cases, being off by
onecould cause problems.
The Friday, 15 April 2005, Arizona Republic had a short "News from home" article from Saginaw, Michigan, about a guy stuck with a bullet in his chest because it is only
5 millimetersaway from his "aortal artery."
Google Search tells us
5 millimeters = 0.196850394 inch.
It is tough to save somebody when a bullet is two-tenths of an inch away from the body's main artery. [ view an inch]
To be completed.