Download The Copernican Cosmos

yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Document related concepts

Non-standard cosmology wikipedia, lookup

Planets beyond Neptune wikipedia, lookup

Corvus (constellation) wikipedia, lookup

Theoretical astronomy wikipedia, lookup

Observational astronomy wikipedia, lookup

De revolutionibus orbium coelestium wikipedia, lookup

Kepler (spacecraft) wikipedia, lookup

Chinese astronomy wikipedia, lookup

IAU definition of planet wikipedia, lookup

Tropical year wikipedia, lookup

Definition of planet wikipedia, lookup

Astrobiology wikipedia, lookup

Aquarius (constellation) wikipedia, lookup

International Ultraviolet Explorer wikipedia, lookup

Formation and evolution of the Solar System wikipedia, lookup

Hipparcos wikipedia, lookup

CoRoT wikipedia, lookup

Stellar kinematics wikipedia, lookup

Rare Earth hypothesis wikipedia, lookup

Satellite system (astronomy) wikipedia, lookup

Comparative planetary science wikipedia, lookup

Planetary system wikipedia, lookup

Tycho Brahe wikipedia, lookup

History of astronomy wikipedia, lookup

History of Solar System formation and evolution hypotheses wikipedia, lookup

Celestial spheres wikipedia, lookup

Planetary habitability wikipedia, lookup

Extraterrestrial life wikipedia, lookup

Orrery wikipedia, lookup

Hebrew astronomy wikipedia, lookup

Astronomical unit wikipedia, lookup

Copernican heliocentrism wikipedia, lookup

Geocentric model wikipedia, lookup

Timeline of astronomy wikipedia, lookup

Dialogue Concerning the Two Chief World Systems wikipedia, lookup

The Copernican
Ptolemaic Universe: “Epicycles Upon Epicycles”
-80 epicycles in the Ptolemaic system
-34 in the Copernican system
 Application of Occam’s razor? Yes.
Epicycles overpopulate the heavens.
Overly complex system.
Three incorrect assumptions
 Earth was the center of the universe
 Uniform circular motion in the heavens
 Planets made from a perfect, unchanging
substance not found on the Earth
Copernican Revolution
 Copernican Revolution is a term which
applies to the transition from a geocentric
cosmological model to a heliocentric
Copernican model
Tycho and Stellar
 Bio (1546-1601)
-scientist (astronomer)
-the nose
-measures the angles between two objects, generally a celestial
object and the horizon
Modern sextant
Why is the sextant
important to science?
Brahe used them for stellar measurements
Better navigation for ships
Observation of a stellar parallax for
Tycho? No, a parallax is not observed until
1838 with the help of a strong telescope.
 Illustration
Tycho’s Cosmological
Tycho’s Cosmological Model
 Tried to reconcile Ptolemaic and
Copernican systems
the five planets orbit the Sun, while the Moon and the Sun orbit the stationary Earth.
Sphere of fixed stars remained. Brahe supported his model by observing that the stars
did not shift (i.e., he could not observe parallaxes).
Other Contributions to
 Studies on the new star of 1572
 Studies on comet of 1574
Both challenge the veracity of the Aristotelian
contention that the heavens are inalternable,
 Tycho’s cosmology merges the Ptolemaic and
Copernican systems. Geocentric universe with
the planets revolving around the sun.
 Why? He could not observe a stellar parallax
(shifting of the stars) which would involve great
distances of empty space which was an
implausible notion (horror vacui-nature abhors a
 Made and used a sextant for stellar
measurements. Sextant has practical uses for
 Discovery of star (nova) of 1572 and comet of
1574 turns Aristotle’s thesis of the inalterability of
the heavens on its head.
 Assumption of uniform circular
motion (planetary circular orbits).
Johannes Kepler
Kepler’s Three Laws of
Planetary Motion
-First Law. Orbit of every planet is elliptical, with the sun as one of the foci.
Kepler’s Three Laws of
Planetary Motion
-Second Law. The radius vector (of a planet) traverses equal areas in equal times.
Kepler’s Three Laws of
Planetary Motion
-Third Law. T 2 = R 3
the square of the time of one orbital period (T2) is equal to the cube of its average orbital radius (R3).
Problem: What is Venus’s average distance from the sun? Well, we know Venus takes 224.7 earth days to orbit the
sun. Venus’s orbital period then would be 224.7/365 or.61 earth years. Since T 2 = R 3, then
.612=R3 or
.3721= R3
3√ .3721
= 3√ R 3
Which would be .71926 AU (astronomical units). If one AU for earth
is 93,000,000 miles, then Venus’s average distance would be
66,859,484.352618 miles.
Next time, class