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

88 views2 pages
23 Aug 2016
School
Department
Course
Professor
Page:
of 2
8/23/2016
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
universe.
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
approached.
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.
find more resources at oneclass.com
find more resources at oneclass.com
8/23/2016
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
summer…)
-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.
find more resources at oneclass.com
find more resources at oneclass.com