Transcript Precession

Precession
As the Earth spins, it “wobbles”
• Similar to a
spinning top
or dreidel
• One wobble
every 26,000
years.
The Changing North Star
• Currently, the North
Pole (N.P.) points
directly towards Polaris
(within a degree)
• Polaris is not/will not
always be the N. Star.
– When the pyramids
were built, it was a small
star called Thubin.
– In 12,000 years, it will
be a bright star called
Vega
– Currently there is NO
South Star 
Does the N. Star move during the night?
• The N. star is the ONLY star that does not
appear to move or change positions.
• The constellations near Polaris that do not rise
or set are called North Circumpolar.
Why did our horoscope signs change?
• “Your sign” should be the constellation the
Sun was in on the day you were born.
• Due to precession (wobble), Earth is not
pointing in the same direction it was when
astrology was first developed. Thus, your
sign has changed!!!
Is astrology science?
• Astrology is a
pseudoscience.
Something that
appears to be science,
but does not follow
scientific methodology
(i.e. scientific method).
• Astrology claims to be
able to predict the
future by the position
of the Sun, stars and
planets.
• Astrologers have
conveniently ignored
the 13th sign of the
zodiac… Ophiuchus.
Poor ophi 
Ophiuchus- 13th sign of the Zodiac