Techniques in Understanding Planets and Stars2

Part 1: Spectrometer

Once you have assembled your spectrometer with the instructions in the lecture, use it to examine the spectra of three different light sources. Make sure that at least

one of them is the sun or moon, but the others can be incandescent lights, compact fluorescent bulbs, LED lights, halogen or xenon bulbs, televisions, computer

screens, candles, fireplaces, etc.

Then, answer the following questions in a separate document:

Describe the differences in appearance among the three spectra.
What feature of the light source do the spectra represent? In other words, what is it that you are actually analyzing?
Why do you think spectrometers are so valuable for studying celestial objects?

Part 3: Solar System Model

Using the lecture on Page 3 of Module 8, answer the following questions using the same document:

Why do you think that the inner planets are relatively close together but the outer planets are spaced so widely apart?
Why do you think that the gaseous planets are gaseous but the inner planets are not?

3. Reconstructing The Solar System
For the following demonstration, we are going to start at Hughes Stadium, the home of the Colorado State University Rams football team. We are going to build a scale

model of the Solar System. The stadium is about 750 feet long so we will use that to scale the size and distances of the planets. If you haven’t seen the stadium, it

is about the size of any mid-level college football or minor league baseball stadium. You might want to follow this using a U.S. atlas or Google Earth!
•    To place Mercury, you would take a pillow from your bed and place it on the other side of Fort Collins to the east or high up in the foothills of the Rockies

to the west.
•    To place Venus, you would place a large sofa in Loveland.
•    Earth would be a king-size bed atop the closest Rocky Mountain peak to Fort Collins.
•    Mars would be an average four- or five-year old human in Greeley, Longmont, or at the Wyoming border.
•    There would be an asteroid belt that circled the stadium from Boulder to Cheyenne, WY.

Figure 3.1: Converted Distances to Objects in the Solar System.
Google Earth
Those were the terrestrial planets. They are small and closely spaced. Let’s look at the gas giants.
•    Placing Jupiter would take us well past Denver, almost to Castle Rock. To the northeast, it would take us into Nebraska and to the west would take us into the

western Rockies, almost to Steamboat Springs. Jupiter would only be the size of a typical, single-level, three-bedroom house.
•    Saturn would be a bit smaller than Jupiter, perhaps a two-bedroom bungalow, but it would be in an orbit that encompasses the Rockies to the east and areas

beyond Colorado Springs to the southeast. To the north, the orbit would almost reach Casper, WY, and to the east it would almost reach Kansas.
•    Uranus would circle Hughes stadium from an orbit that includes Taos, NM to the south, North Platte, NE, to the east, the Montana border to the north, and the

panhandle of Oklahoma to the south. We are just shy of reaching Texas and Salt Lake City, UT. Uranus would be the size of an elephant.
•    Neptune would also be an elephant, but its orbit would range past Amarillo, TX, to the southeast, Wichita, KS, to the east, Bismarck, ND, to the northeast,

Idaho Falls, ID, to the northwest, the Nevada border to the west, and the Grand Canyon to the southwest.
•    The Kuiper Belt is a belt of asteroids beyond Neptune that includes the dwarf planet, Pluto. Pluto would be a basketball, but it would be in Missouri to the

east, Mexico to the south, Las Vegas to the west, and Canada to the north.
So how much farther would we have to go to reach the edge of our solar system? From Hughes Stadium, the edge of the Solar System would be in Fairbanks, AK, to the

northeast, Costa Rica to the south, Jamaica to the southeast, Bermuda to the east, Greenland to the northeast, and the Arctic Ocean to the north.
References