Astronomy Lab #1 Creating a Scale Model of our Solar System

Background Information: According to a scientific theory called the “Big Bang,” twelve billion years ago there was nothing (no planets, no stars, no light, nothing) then…something happened and there was an incredibly dense and small speck filled with light. A fraction of a second later, the Universe expanded outward from this tiny speck and all matter was formed.

All of the galaxies in the Universe are still moving away from each other as the Universe expands. Our Solar System is located within the Milky Way galaxy, a spiral-shaped galaxy within the Local Group (a cluster of galaxies) that is 100,000 light-years across. [A light-year is how far light travels in one year or 5,900,000,000,000 (5.9 trillion) miles.] Astronomers believe there are about 200 billion stars within our galaxy (counting to 200 billion would take you 3,000 years if you were to count two numbers per second and never stop for a break.) Everything you see with the naked eye in the night sky is part of the Milky Way galaxy. Our nearest neighboring galaxy is the named M31, or the Andromeda galaxy, which is 200 million light-years away.

According to another scientific theory, our Solar System is believed to have evolved about 4.6 billion years ago from a large cloud of interstellar gas and dust. The cloud then collapsed inward and the center got hotter and denser, eventually forming the Sun. Meanwhile the outer parts of the cloud were spinning and spreading out; as smaller particles of gas and dust collided, they stuck together forming the planets.

Our Solar System is located approximately 30,000 light-years from the center of the Milky Way galaxy. Planet Earth is about 93 million miles (149.6 million km) away from the sun. Since our Solar System is so large, we have designated the distance from the Sun to Earth as one Astronomical Unit (A.U.) and commonly use this as a unit of measurement.

Part 1: Planet Distances

Questions: What planets make up our Solar System?

How are the planets arranged/ordered?

How large is our solar system?

How far apart are the planets?

Materials:

1 Roll of Toilet Paper

9 “Sticky Note” Papers

Pen or Pencil

Procedure:

Scale: For this activity, we will use a scale of 1 Astronomical Unit (A.U.) equal to 10 squares of toilet paper.

  1. Multiply each of the planet’s A.U. distance (given in Table 1 below) by 10 (second column of Table 1) to calculate where to place the planets along the rolled-out toilet paper. Record the information in the fourth column of Table 1.
  2. Label your sticky notes by writing the name of one planet on each piece until all 9 are labeled with a different planet.
  3. Roll out the toilet paper and count the squares to determine where to place each of the planets along the roll. Place the planet sticky notes.

Table 1: Distances from Each Planet to the Sun

Planet

/ Actual Distance From Sun (A.U.) / Multiply by Scaled A.U. Distance
(TP Squares) / Scaled Distance from Sun
(TP Squares)
Mercury / 0.39 / 10 / 3.9
Venus / 0.72
Earth / 1.0
Mars / 1.52
Jupiter / 5.2
Saturn / 9.55
Uranus / 19.2
Neptune / 30.1
Pluto / 39.4
  1. Make a scaled drawing of your Solar System showing the location of each planet from the Sun.
  1. Calculate what the scaled distance from the sun to each planet would be if I wanted to create a scale model of our solar system in Room 125. (Use 12 meters for the length of the room.)

Hint: First, determine the maximum number of centimeters each A.U. could be if the Sun were on one wall and Pluto was on the opposite wall (i.e., if 39.4 A.U. equals 12 meters so how many A.U. are in 1 meter?) Record this information in the third column of Table 2.

  1. Record your results in the fourth column of Table 2.

Table 2: Scaled Distance from Each Planet to the Sun in a 12 Meter Room

Planet

/ Actual Distance From Sun (A.U.) / Divide by Scaled A.U. Distance
(A.U./m) / Scaled Distance from Sun in 12 Meter Room (m)
Pluto / 39.4 / 3.28 / 12
Neptune / 30.1
Uranus / 19.2
Saturn / 9.55
Jupiter / 5.2
Mars / 1.52
Earth / 1.0
Venus / 0.72
Mercury / 0.39

Reflections:

What patterns do you observe concerning the distances between planets in your model?

Does anything about your scale factor calculations surprise you? Explain your answer.

What do you notice about the planets compared to the space around them?