Download Early Astronomy Pre-Renaissance (the west)

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Early Astronomy
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Dealt with movement of
the Sun, Moon, and stars
Keep time, seasons, and
determine direction
Pre-Renaissance (the
west)
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Made measurements of the
stars
Use simple idealized
models in the West, more
sophisticated models in
the East
Astronomy and History
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Renaissance (west)
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Used science preserved in
the East to resurrect
Western science
Devised better models
Modern Science
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Natural science (physics)
applied to astronomy
Better mathematical tools
(calculus and beyond)
Astronomy and Science Preserved
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Before and after renaissance;
what happened?
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Initially, science progresses
in ancient Egypt, Greece,
and Italy (Rome) - West
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But, science falls back in the
west during the “Dark Ages.”
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However, science is
preserved by Eastern
scientists
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Eventually, science is
recovered by Western
scientists
Astronomy's legacy to history
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Now that we discussed history we need to
discuss the “jargon” used by astronomers
that has its roots in history
The next couple of slides will do that
Astronomy's legacy
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Celestial Sphere is an
imaginary sphere that has
the Earth as it center
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Celestial objects rest on
the sphere
Celestial equator, celestial
north pole, and celestial
south pole are projections
from the Earth
Assumes stars are
equidistance from the
Earth
Astronomy's legacy
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Right Ascension and
Declination used to describe
position of celestial objects
Uses angles and hence
trigonometry for advance
calculations
Right Ascension and
Declination (RA, Dec) are
heavily used today even
though they are based off a
“celestial” sphere concept
Classical Astronomy
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Celestial Sphere
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“latitude” is declination (dec)
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0 degrees is the celestial
equator
+90 is North Celestial Pole
-90 is South Celestial Pole
“longitude” is right ascension
(RA)
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Measured in hours rather
than degrees
Uses “the First Point of
Aries” as 0 hours (and 24
hours)
1 hour = 15 degrees
Changes in time and date!
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Due to Earth Procession
Classical Astronomy
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Vernal Equinox IS the
First Point of Aries
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Where celestial
equator intersects the
ecliptic
In Pisces now and will
be in Aquarius in
2600AD
Zodiac/Zodiacal Light
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Planets move in band that
is 23.5 degrees from the
Celestial equator
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Called the Zodiac (“Little
Animal”)
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Constellations
Stars grouped based of
Celestial Sphere
Pluto doesn't though...
Zodiacal Light
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Faint Light corresponding
to Zodiac
Believed to be reflection
by dust particles around
the solar system
Zodiacal Light (The Zodi)
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The S in images of
the infrared sky
Between the Sun and
Jupiter
Evidence was initial
found because the
spectrum resembled
our own solar system
(hence must be
reflection)
The Zodiac (Astrology)
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Astronomy is NOT
Astrology
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Astrology is akin to a
religion, astronomy is a
science
Astrology however did
provide the background
for Astronomy in ancient
civilizations
Clearly still use the terms
(the Zodi)
The Solar System
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The Solar System
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Sun
Mercury
Venus
Earth
Mars
Asteroid belt (Ceres!)
Jupiter
Saturn
Uranus
Neptune
(Pluto) – Dwarf planet
(Eris originally known as
Xena) – Dwarf planet
Kuiper belt
Oort Cloud
The Solar System
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Kuiper Belt
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From within
Neptune’s orbit to 50
AU from the Sun
Trans-Neptunian
objects (minor
planets)
Kuiper gap
Oort Cloud (theory)
The Planets
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Kepler’s Law
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Planets in elliptical orbit
around the Sun (the Sun is
one focus point)
Orbit speed varies so that
in equal time intervals
equal area will be swept
Amount of time a planet
takes to orbit the Sun is
related to its orbit’s size