kotturi
The Earth as a Planet
It is important to look at the Earth in its context as only one of the nine planets which make up the solar system.
This is an introduction to the Solar System, its formation, and composition, with special emphasis on the "terrestrial" or "inner" planets. I take a kind of historical approach, noting the patterns and regularities observed, for example, by Tycho Brahe, described by Johannes Kepler, and explained by Sir Isaac Newton. Laplace and even the philosopher Immanuel Kant figure into shaping our modern-day notions of the origin and composition of the solar system.
"Early attempts to explain the origin of this system include the nebular hypothesis of the German philosopher Immanuel Kant and the French astronomer and mathematician Pierre Simon de Laplace, according to which a cloud of gas broke into rings that condensed to form planets."
Let's start by looking at some patterns in the solar system:
Titius-Bode Law
Taking the point of view of a first-time visitor, one of the first things you would notice about the Solar System is that the spacing between the planets' orbits consistently increases as you move away from the Sun (with one exception). Furthermore, it's not a linear increase, so we need essentially two figures, at different scales, to represent the solar system (pictures courtesy of "The Nine Planets"):
Titius-Bode's law: Distance, r, of the nth planet from the Sun (in A.U.s) is given by: rn = 0.4 + 0.3 x 2n
Planet
n rn Actual
Mercury
-infinity, -1
0.4, 0.55
0.39
Venus
0
0.7
0.72
Earth
1
1.0
1.0
Mars
2
1.6
1.52
Asteroids
3
2.8
-
Jupiter
4
5.2
5.2
Saturn
5
10.0
9.6
Uranus
6
19.6
19.2
Neptune
7
38.8
30.1
Pluto
8
77.2
39.4
The Titius-Bode law was used to help discover Ceres, a 1000 km asteroid, in 1802, and Uranus in 1781.
Check satellites of Saturn and Jupiter
Law has never been given a scientific foundation, and may be "chance," combined with the fact that the outer
It is important to look at the Earth in its context as only one of the nine planets which make up the solar system.
This is an introduction to the Solar System, its formation, and composition, with special emphasis on the "terrestrial" or "inner" planets. I take a kind of historical approach, noting the patterns and regularities observed, for example, by Tycho Brahe, described by Johannes Kepler, and explained by Sir Isaac Newton. Laplace and even the philosopher Immanuel Kant figure into shaping our modern-day notions of the origin and composition of the solar system.
"Early attempts to explain the origin of this system include the nebular hypothesis of the German philosopher Immanuel Kant and the French astronomer and mathematician Pierre Simon de Laplace, according to which a cloud of gas broke into rings that condensed to form planets."
Let's start by looking at some patterns in the solar system:
Titius-Bode Law
Taking the point of view of a first-time visitor, one of the first things you would notice about the Solar System is that the spacing between the planets' orbits consistently increases as you move away from the Sun (with one exception). Furthermore, it's not a linear increase, so we need essentially two figures, at different scales, to represent the solar system (pictures courtesy of "The Nine Planets"):
Titius-Bode's law: Distance, r, of the nth planet from the Sun (in A.U.s) is given by: rn = 0.4 + 0.3 x 2n
Planet
n rn Actual
Mercury
-infinity, -1
0.4, 0.55
0.39
Venus
0
0.7
0.72
Earth
1
1.0
1.0
Mars
2
1.6
1.52
Asteroids
3
2.8
-
Jupiter
4
5.2
5.2
Saturn
5
10.0
9.6
Uranus
6
19.6
19.2
Neptune
7
38.8
30.1
Pluto
8
77.2
39.4
The Titius-Bode law was used to help discover Ceres, a 1000 km asteroid, in 1802, and Uranus in 1781.
Check satellites of Saturn and Jupiter
Law has never been given a scientific foundation, and may be "chance," combined with the fact that the outer