Read
Seeds: Section 5.2
| Read
Seeds: Section 5.2 |
| Activity: The properties of our
solar system provide clues to how our solar system formed. Like a detective
who must recreate a crime on the basis of existing clues, so too must an
astronomer establish hypotheses of how the solar system formed on the basis
of existing evidence. What is that evidence? Complete a search of the Planetary
Data Browser and determine some of the properties of our solar system.
Print out a copy of the output of your query for future reference.
The search should include these criteria: a. Selected type of data to use: Planets Only >Planetary Data Browser. Print out a copy for your own reference. You may also mail be a copy for question 7 in the homework. (2 points) The search should include these criteria: a. Selected type of data to use: Planets Only b. Sort the information by: Planetary Order c. Sort: Down d. Selected Information to be included: Distance, Radius, Mass, Density, Orbital Period, Inclination, Tilt of Axis, Eccentricity, Escape Velocity, Rotational Period |
From this and other data, we can make the following generalizations about our Solar System:
The composition of the solar system is typical of that of the universe.
99.87% of the mass
of the solar system is in the Sun.
The data in
the data table provides information only on the planets. The mass of the
Earth, for example is 5.976e+24 kilograms (interpreted 5.976 times 10
raised to the 24th power kilograms). It is pretty humbling to think the
combined mass of the planets, their moons, the comets and asteroids make
up only .13% of the mass of the solar system. The Sun makes up the other
99.87%. Even more humbling is the fact that that .13% is the planet Jupiter.
The orbits
of the planets are nearly circular.
Although we
learned in the previous unit that the orbits of the planets are ellipses,
with the Sun located at one of the two foci. In fact, the eccentricities
of their orbits is nearly circular, with eccentricities close to "0".
(Refer to the column labeled "Eccen." on your data table.)
The orbits
of the planets lie in nearly the same plane.
The orbits of each of the planets lie in a plane. This plane is referred
to as the "orbital planet" (def.)
The inclination (def.)of
the orbital planes of the planets is within 4 degrees of the ecliptic
with the exception of two planets. (Refer to the column labeled "Incl."
on your data table.)
All of the
planets orbit the Sun in the same direction.
The planets all orbit the Sun in an eastward direction.
All
of the planets, except two, rotate in the same direction as they revolve.
We saw
in the discussion
of rotation that the Sun and other celestial bodies rise in the east
because of the Earth's eastward rotation. All but two of the planets rotate
eastward.
Most of the planets
are tilted on their axis by only a small amount.
(Refer to the
column labeled "Tilt" on your data table.)
The planets
fall into two distinct categories, the terrestrial planets and the jovian
planets.
There is a tendency to think of a planet as being "earthlike". However,
our solar system has two distinct and different types
of planets. The terrestrial planets are those planets that are similar
to the Earth. The jovian planets are those that are similar to Jupiter.
The Oort comet
cloud
Surrounding
the solar system is a spherical cloud having a radius of 100,000 AUs.
It is thought to be the source of long period comets.
Complete
these Self-check Questions:
Homework Questions: (To submit your answers to the homework questions, first copy the questions from this page and paste them into the homework form. Insert your answers below the questions. Fill in the remaining form elements and submit. Your homework will be e-mailed to me. I will return your graded homework to you in the private e-mail of the comm center).
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| Fred
Hickok Updated: January 17, 2001 |
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