It is your job, over the next week to ten days or so, to fill in the table at the bottom of this page using the Web links listed in the web-based lecture notes on the planets. To do so, follow the steps:

• For each planet, links are provided whereby you can obtain general/basic information such as mass, volume, etc. Use those links to find the information, and include it in the table.
• Note that in the table, specific units (e.g., kg, km etc.) are required. If you find information that is not in those units, please convert to the units requested.  We discussed unit conversion, in some detail, in the lecture in "Light and Atoms". Take a look at those lecture notes if you are unsure.
• For a couple of entries, you are asked to also include the values compared to those of the Earth. For example, if you list the mass of a planet in kg, you are also asked to express the mass relative to the Earth. To do that, simply divide the planet’s value by the Earth’s value. For example,

• Distance from the Sun in A.U. : Fill in the planets distance in astronomical units.  Recall that 1 A.U. is the mean orbital distance of the Earth from the Sun.  The units will obviously be in A.U.
• Eccentricity, e,  of the Orbit: The eccentricity is how non-circular the orbit is.  An orbit with an eccentricity of zero is circular, while higher eccentricities indicate more non-circular orbits.  The units will be measured in degrees.
• Orbital Velocity: This is precisely what is says, the average speed at which the planet travels in its orbit.  The units here should be km/sec.
• Orbital Period: How long does it take the planet to complete one orbit of the Sun?  Here the units should be years.
• Inclination, i, of Orbit : Recall that the Earth orbits the Sun in a plane. The other planets also orbit the Sun in planes, but they are not necessarily aligned with the plane of Earth’s orbit. That is, they are inclined to the Earth’s orbital plane. The inclination tells how many degrees the planet’s orbital plane around the Sun is inclined to that of the Earth’s.   The units, therefore, should be degrees.
• Rotational Period: How long is a given planets "day"?  That is, how long does it take to rotate once on its axis, which defines its "day".  That time is the rotation period, which here should be expressed in days.
• Number of Satellites: How many moons does the planet have. Recall that this tells us if we can estimate its mass without resorting to manmade spacecraft!
• Mass : What is the mass of the planet in kilograms (kg)? If you find the mass in other units, you will have to convert to kilograms. Additionally, you need to also tell how massive the planet is compared to Earth . To do this, simply divide the mass of the planet by the mass that you find for the Earth.
• Radius : What is the radius of the planet in kilometers (km)? If you find the radius in other units, you will have to convert to kilometers. Additionally, you need to also tell how the radius of the planet compares to Earth . To do this, simply divide the radius of the planet by the radius you find for Earth.
• Density : What is the density of the planet in grams per cubic centimater (g/cm³)? Recall that density is the amount of mass (from above) in a given volume (found from the radius - for a sphere the volume is 4/3piR³). It is possible to find the volume itself on some of the Web sites listed.   Alternatively, you can calculate the volume of the planet by using its radius.   Note that you want the mass in grams (not kilograms!) and the radius must be in centimeters (not kilometers), so that the density will be in grams per cubic centimeters (cm³).   If you find the values in other units, you will have to convert!
• Surface Gravity, g : Surface gravity is a measure of how much you would weigh on a given planet.  For example, the Moon’s surface gravity is 1/6 that of the Earth, or . This means that on the Moon, you would weigh one-sixth what you weigh on the Earth!  It is possible that you will find the surface gravity for the planet, on the Web, listed as I did above; that is compared to that of the Earth.   If you find it listed with units of acceleration (e.g., m/sec²), you will have to take the ratio of the planets surface gravity to that you find for the Earth (9.8 m/sec²).
• Escape Velocity : Escape velocity tells how fast an object must be going in order to escape the planet, and move into "deep space".  In other words, it gives you an idea of how "big" a rocket you need to escape from the planet.   Here the units should be km/sec.
• Surface Temperature : What is the temperature, or range of temperatures, on the planet? If you find it listed with units other than Fahrenheit (e.g., Celsius or Kelvin), you will have to convert units. To do so, see the discussion of temperature scales in the lecture on "Light and Atoms".

    So on to the table!