ASTR 1013 Lecture Notes - Lecture 2: Gregorian Calendar, Orbital Speed, Pseudoscience

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23 Aug 2016
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ASTR 1013 2nd Lecture
2.1 University Science
-Professors do long-range research. Annual economic return 20-60%.
-They communicate discoveries via conferences, journals, and publications
-They submit proposals to federal agencies for funding
-They train future scientists and engineers
-Astronomers observe and then analyze at their home university
2.2 Pseudoscience
-Claims to be scientific, but violates at least one scientific principle
2.3 Religion
-Belief in, and reverence for, superhuman power(s) that created and/or govern the universe
-Belief= Acceptance as truth
-Science does not preclude religious belief; religion should defer to science about the physical
2.4 Astrology
-Ancient superstition of celestial influences on people, based on location of sun and planets
relative to the 12 Zodiacal constellations
2.5 UFOs
-Existence of extraterrestrials is plausible, but not supported by evidence
3.1 The Terrestrial Globe
-Meridians and parallels. Positions described by latitude (angle N/S of the Equator) and
longitude (angle E/W of the Prime Meridian). East is the rotational direction
-Angles are measured in degrees, arcminutes (‘), and arc seconds (“). 1 degree= 60’=3600”.
Meridians converge at pole, so physical length of 1 degree of longitude shrinks as poles are
3.2 Days and Time
-Sidereal Day=23hrs 56min= time for Earth’s 360 degree rotation
-Apparent Solar Day. Range is 24hrs+/- 30sec= time between successive sunrises. Corresponds
to 360-362degrees rotation. Earth’s changing orbital speed and tilted axis cause the variation
-Mean Solar Day. The time between successive passages of the mean sun across the meridian.
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3.3 Years and Calendars
-Sidereal Year=365.2564 days= time for one true orbit
-Tropical Year=365.2422 days= time for season repetition (winter to winter, summer to
-Gregorian Calendar. Instituted in 1582 to match calendar to the Tropical Year rule. Years have
365 days with every 4th year having 366 with few exceptions.
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