Astronomy = Timekeeping Day, month, year Important for seasons - hunter gatherer Annual migrations Seasons important for farmers Heliacal rising of Sirius Important for navigation Longitude & GPS Important for modern society Time stamps on files
In a year the Sun appears to move 360 along the Ecliptic ~ the Zodiac
Ecliptic and Zodiac Mercator projection map of celestial sphere in ecliptic & equatorial Shows position of Sun at Summer Solstice 21Jun, Autumnal Equinox 21Sep, Winter Solstice 21Dec, Vernal Equinox 21Mar 21Mar 21Dec 21Sep 21Jun 21Mar
Seasons Earth s axis tilted 23 Sun appears higher in sky in summer Longer days Sun shines down more directly
Precession Earth rotates like a gyroscope Pulled by Sun and Moon Earth precesses so the axis of rotation points to different stars circles in 26,000 years North star was Thuban 3000BC when pyramids were built Sun in Gemini on 21Jun not Cancer Tropic of Cancer?
Julius Caesar (July) Reformed Calendar 46BC Sidereal Year is 1 orbit around sun Tropical Year (Calendar Year) is from Vernal Equinox to Vernal Equinox But Equinox precesses with Earth s pole Year is 365.24219 days Abolished extra month Set months to present number of days Add 1 day every 4 years to February Quintilius renamed July (ius) Sextilis renamed August (us) Sept should have been 7
Gregorian Calendar Julian calendar worked until 5-14 Oct 1582 when Pope Gregory dropped 10 days England & colonies reformed, 3-13 Sept 1752 Russia in 1917 Skip leap year when year ends with 00 Keep leap year when year evenly divisible by 400
The seasons change during the year because: a. Because we have Daylight Savings time, the days are longer in the summer and its hotter b. Of precession of Earth s axis of rotation c. Tilt of the Earth s axis of rotation to the ecliptic causes sun to shine more directly in summer d. The winter solstice is in December and the summer solstice is in June e. We are closer to the sun in the summer so it s hotter
Sidereal and Solar Day Earth rotates once with respect to the stars in one Sidereal Day But Earth orbits the sun (revolves around) So it must rotate a little extra to point to the sun again for one Solar Day 4 minutes or 1 degree each day
Names of the Days of the Week Latin Old English English German French Italian Spanish Dies Solis Sun's Day Sunday Sonntag dimanche Domenica domingo Dies Lunae Moon's Day Monday Montag lundi Lunedì lunes Dies Martis Tiw's Day Tuesday Dienstag mardi martedì martes Dies Mercurii Woden's Day Wednesday Mittwoch mercredi mercoledì miércoles Dies Jovis Thor's Day Thursday Donnerstag jeudi giovedì jueves Dies Veneris Frigg's Day Friday Freitag vendredi venerdì viernes Dies Saturni Seterne's Day Saturday Samstag samedi sabato sábado Named after the seven planets = wanderers Not in the right order??? 4 7 day weeks almost = a month
Self Consistent Horoscopes? Eugenia Last in Van. Sun Aries: A partnership can help you expand your interests and take on tasks you have not done in the past. Uncertainty regarding a job or career choice can be dealt with if you take control and make the necessary changes before someone makes a decision for you. Sally Brompton in TC Tues. Aries: Your current situation may look chaotic but if you stand back and look at it from a distance you should be able to see a pattern beginning to emerge. The same applies to your life in general: it does have a meaning.
Astrology the Pseudoscience Astrology makes predictions (sort of) so test American Marines who re-enlist show no correlation with birth date Any reasonable/logical connections Signs and planets on far side of Earth have effect but only after birth not conception. Tides of the Doctor larger than moon
1. Aries March 21-April 19 2. Taurus April 20- may 20 3. Gemini May21-Jun20 4. Cancer Jun21-July22 5. Leo July23-Aug22 6. Virgo Aug 23-Sept22 7. Libra Sept23-Oct22 8. Scorpio Oct23-Nov21 9. Sagittarius Nov22-Dec21 10. Capricorn Dec22-Jan19 11. Aquarius Jan20-Feb18 12. Pisces Feb19-Mar20
Month From new moon-new moon=one month=29.53 days 12 months=354.37 days Islamic calendar = lunar calendar: slips relative to seasons Chinese, Hindu, Hebrew add extra month to some years
Mean Solar Day Because the Earth does not orbit the sun at a constant distance or speed, Sun appears fast or slow Ecliptic at angle to Equator so sun s motion is parallel to Equator at Solstice & at angle at Equinox Mean Sun travels at average rate