Transcript Solar System Notes

The Planets
First things first…
Rotation – a circular movement of an object
around a center (or point) of rotation;
rotation around an axis
Sidereal Day – The
time it takes for a
planet to make one
complete rotation on
its axis.
Revolution:
The action by a celestial body of going
round in an orbit or elliptical course.
“Copernicus proposed the heliocentric
model for the solar system, which had the
planets revolving around the Sun instead of
the Earth.”
Back in the olden days…
Ptolemy put forth a geocentric, or
“Earth-centered” model of the
solar system based on his
observations and those of his
predecessors. His geocentric
model showed the Sun and other
planets revolving around the
Earth, and the universe as a set of
nested spheres.
Claudius Ptolemaeus
(90-168A.D.)
This was the main model until…
Nicholas Copernicus, a Polish
mathematician, astronomer, physician,
classical scholar, translator, artist, Catholic
cleric, jurist, governor, military leader,
diplomat and economist developed a
heliocentric, or “sun-centered” model
for the solar system, whereby the planets
revolved around the sun in circular paths.
His work is regarded as the beginning of
modern astronomy, and the defining
epiphany that started the Scientific
Revolution. His contributions are often
referred to as the Copernican Revolution.
His theories were later confirmed by…
Nicolaus Copernicus
(February 19, 1473 – May 24, 1543)
Galileo Galilei, an Italian physicist,
mathematician, astronomer, and
philosopher who has been called the
“father of modern observational
astronomy” for his many contributions,
including refinements to the refracting
telescope with which he confirmed
the phases of Venus, the discovery of
the four largest satellites of Jupiter, and
the observation and analysis
of sunspots.
Galileo Galilei
(15 February 1564 – 8 January 1642)
Galileo’s beliefs led to trouble with the
Catholic Church, and he was eventually
forced to recant heliocentrism. He spent
the last years of his life under house
arrest on orders of the Roman
Inquisition.
Johannes Kepler was a German astronomer
who discovered three major laws of planetary
motion, conventionally designated as follows:
(1) the planets move in elliptical orbits with
the Sun at one focus;
(2) the time necessary to traverse any arc of a
planetary orbit is proportional to the area
of the sector between the central body and
that arc (the “area law”); and
(3) there is an exact relationship between the
squares of the planets’ periodic times and
the cubes of the radii of their orbits (the
“harmonic law”).
Kepler’s discoveries turned Nicolaus
Copernicus’s Sun-centred system into a
dynamic universe, with the Sun actively
pushing the planets around in noncircular
orbits. And it was Kepler’s notion of a
physical astronomy that fixed a new
problematic for other important 17th-century
world-system builders, the most famous of
whom was Newton.
Johannes Kepler
(27 December 1571 – 15 November 1630)
Sir Isaac Newton
Newton was an English
physicist, mathematician,
astronomer, natural philosopher,
alchemist, and theologian and
one of the most influential men
in human history.
Among many other things, he is
credited with describing the
Universal Law of Gravitation and
the Three Laws of Motion.
A 2005 survey of the British
Royal Society ranked Newton
ahead of even Einstein as
having a greater influence on
the history of science.
January 4th, 1643 – March 31st, 1727
Wow! That was a lot of information!
Let’s break it down…
Ptolemy put forth the idea that the Earth was at the center of the universe and
was surrounded by concentric crystal spheres which held the sun and planets.
Later, the work Copernicus did showed that Ptolemy’s ideas were incorrect, and
that instead of the Earth, it was in fact the Sun that was at the center of the
universe and the planets went around the Sun in circular orbits.
This heliocentric theory was confirmed by Galileo with his work with that new
piece of technology, the telescope.
Around this same time, Kepler calculated that the orbits were not circular, as
described by Copernicus, but rather were elliptical (oval) in shape.
Newton, using the calculus that he co-invented, confirmed this idea of elliptical
orbits of the planets. He showed through his calculations that they were held in
their orbits by gravity, a concept that he described using his 3 Laws of Motion and
his Theory of Universal Gravitation.
The
Formation
of our Solar
System
https://www.youtube.com/watch?v=Uhy1fucSRQI
How do we know?
Observations…
Protoplanetary disc
forming around HL Tau, a
young star at about 1
million years old.
This photo was captured by ALMA, the Atacama Large Millimeter/submillimeter Array — a giant telescope consisting of
66 individual antennas, located high up in the Atacama desert in northern Chile.
Take a look at this picture.
What do you notice about the orbital
speeds of the planets?
But let’s stop and put things in perspective…
Push here to
compare our Sun and
Planets to other
objects in the
Universe
Push here to see
how vastly,
hugely, mindbogglingly big the
Universe is.
The Terrestrial Planets
Venus
Earth
Mars
Mercury
Color = Yellow
Due to clouds of
sulfuric acid
One rotation takes
243,01 days and is
retrograde, meaning
it rotates clockwise
(opposite of Earth)
Color = Blue
Due to oceans of
liquid water
Color = Red
Due to iron oxide
in weathered
rocks on the
surface
The Jovian Planets
Jupiter
Saturn
Uranus
Neptune
Just the data, Spock…
Nam e
Terrestrials
Jovian
Equatorial
Mass[a]
diam eter[a]
Orbital
radius
(AU)
Orbital
period
(years)
Nam ed
m oons
Rings
Atm osphere
Mercury
0.382
0.06
0.39
0.24
—
no
minimal
Venus
0.949
0.82
0.72
0.62
—
no
CO2, N2
Earth
1
1
1
1
1
no
N2, O2
Mars
0.532
0.11
1.52
1.88
2
no
CO2, N2
Jupiter
11.209
317.8
5.2
11.86
49
yes
H2, He
Saturn
9.449
95.2
9.54
29.46
52
yes
H2, He
Uranus
4.007
14.6
19.22
84.01
27
yes
H2, He
Neptune
3.883
17.2
30.06
164.8
13
yes
H2, He
[a] Measured relative to the Earth.
Look carefully at this chart and notice the differences
between the Terrestrials and the Jovians.