AY 102 Lecture Notes - Lecture 4: Copernican Revolution, Orbital Period, Semi-Major And Semi-Minor Axes

26 views3 pages
24 Jan 2018
Department
Course
Professor
AY Lecture 4 1-24-18
Historical Underpinnings of Astronomy
The view of the location of Earth in the universe changed from:
- Geocentric (Erath-centered) to
- Heliocentric (Sun-centered
Six early scientists contributed to these development in astronomy:
- Ptolemy
Famous geocentric model of planetary motion
Plaets oe i irles o irles aroud the Earth
- Copernicus
Proposed heliocentric model
- Brahe
Precise observations of planetary positions
- Kepler
Using these observations, derived three empirical laws of planetary motion
Planets move along elliptical paths around the sun
- Galileo
Using a telescope to discover mountains on the moon, the moons of Jupiter,
sunspots, and the phases of Venus
- Newton
Using math to derive physical laws of motion and developed the universal law of
graitatio that eplaied Kepler’s las
What are planets?
- aderig stars
- ostellatios defie fied stars
Seeking evidence that Earth is also a planet and that it moves
- Two observations favored a heliocentric view
Retrograde motion of Mars, Jupiter, and Saturn
Venus and Mercury can never be seen at midnight
Normally planets move west to east in the sky, but every 780 days, Mars temporarily reverses
its oeet goes retrograde
- What causes this retrograde motion?
It is aused  a real loop i Mars’ orit
Heliocentric view
- Retrograde motion is an illusion caused by the relative movement of the Earth and a
planet moving on a larger, slower orbit around the sun
Retrograde motion occurs when an outer planet is at opposition. At this time, an outer planet:
- Is opposite the sun in the sky
- Is closest to Earth
- Rises at sunset and set at sunrise
- Crosses the meridian at midnight
find more resources at oneclass.com
find more resources at oneclass.com
Unlock document

This preview shows page 1 of the document.
Unlock all 3 pages and 3 million more documents.

Already have an account? Log in

Get OneClass Notes+

Unlimited access to class notes and textbook notes.

YearlyBest Value
75% OFF
$8 USD/m
Monthly
$30 USD/m
You will be charged $96 USD upfront and auto renewed at the end of each cycle. You may cancel anytime under Payment Settings. For more information, see our Terms and Privacy.
Payments are encrypted using 256-bit SSL. Powered by Stripe.