lec01_26sep2011

lec01_26sep2011 - Lecture 1 What can the solar system tell...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture 1 – What can the solar system tell us about the Let’s consider: 1. The sun. 2. The “major planets.” 3. Small bodies, including the Kuiper Belt and laboratory samples.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
He H O C N Si All Else Fe What is the composition of the sun? Are other stars similar? [O,C] ~10 -4 [H] [N] ~10 -5 [H] [Si,Fe]~10 -6 [H]
Background image of page 2
The answer is time dependent! Impact? Cosmic background imaging   (WMAP),  τ =13.7 AE (~1%),  no/little “metals,” 4% atoms,   23% CDM, 75% Dark Energy. Large scale   structure. β Pic, a nearby   young star & disk.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Laplace: The System of the World (1796) Although the geometrical elements of the planetary system are physically independent of each other, there are, nevertheless, certain relationships among them which can clarify their origin. On close consideration, it is astonishing to find all the planets moving about the sun from west to east and almost in the same plane; all of the satellites move about their planets in the same sense and nearly in the same plane as the planet; finally, the sun, the planets and their satellites, whose rotary motion we can observe, turn on themselves in the direction and nearly in the plane of their orbital motion. Such an extraordinary phenomenon can hardly have haphazard causes; it suggests that a general cause has established all of the motions. To obtain an estimate of the probability of such a cause, we remark that the planetary system as it is known today, comprises seven [planets] and fourteen satellites; we have observed the rotation of the sun, of five planets, of the moon, the ring of Saturn and one of his moons. These form an ensemble of thirty motions directed in the same sense. An equally remarkable phenomenon of the solar system is that the orbits of the planets are nearly circular, while those of the comets are highly elongated; the orbits of the system offer no intermediate nuances. Again we are compelled to recognize the effect of a regular cause; happenstance alone could not possibly give an almost circular form to the orbits of all the planets. Whatever arranged these orbits also made them nearly circular. Moreover, the same cause must explain the great elongation of cometary orbits, and the fact that comets move in all directions as though they had been thrown at random. Thus to trace back to the cause of the original motions of the planetary system, we have the following five facts: the motions of the planets in the same direction, and in almost the same plane; the motions of the satellites in the same direction as that of the planets; the rotary motions of these various bodies, and of the sun, in the same directions as their trajectories about the sun and in approximately the same planes; the nearly circular orbits of the planets and satellites; finally, the great elongation of the orbits of the comets, although their orientations have been left to chance . (see http://eee.uci.edu/clients/bjbecker/ExploringtheCosmos/week8c.html)
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 10

lec01_26sep2011 - Lecture 1 What can the solar system tell...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online