Question: in our everyday life we are used to humansize distances...
In our everyday life, we are used to human-size distances: in the US, when we deal with short distances or small objects we use inches, then yards for intermediate distances, and miles for longer distances. In science (and in most countries), distances are measured using the metric system: millimeters or centimeters are utilized for very short distances, meters for intermediate distances, and kilometers for large distances. However, in astronomy distances are so huge that larger units must be used (Astronomical Units within the solar system, light years or parsecs for interstellar and intergalactic distances) and it is hard to put these distances in perspective. In this first lab, we will shrink down different astronomical objects to the size of a tennis ball (6.5 cm) and get a sense of the relative proportions and distances by using objects of common knowledge like basketballs, basketball courts, soccer fields, and the length of Virginia, which are related to each other in the following way.
- Basic unit: 1 tennis ball
- basketball = 4 tennis balls
- basketball court = 100 basket balls
- Soccer field = 3 basketball court
- State of VIrginia = 7000 soccer field
Part II – Milky Way in a tennis ball
In this third scaling model, we shrink the Galaxy diameter to the size of a tennis ball, and then use the same scale to put in perspective the distance to two nearby galaxies: Andromeda and the Triangulum Galaxy. For this exercise, let’s assume the following values:
Galaxy diameter 100 thousand light years (1 ly= 9.46 trillion km)
Andromeda distance 2.5 million light years
Triangulum Galaxy 3.0 million light years
- Before doing the actual calculations, you should estimate the distances in the Galaxy-tennis ball model. Is the scaled distance of Andromeda of the order of few tennis balls, basketballs, basketball courts, soccer fields? What about the estimate of the scaled distance of the Triangulum Galaxy? How big would be the Earth and the solar system in this model?
Estimate of the Andromeda galaxy scaled distance= …
Estimate of the Triangulum galaxy scaled distance= …
- Do the calculations for Andromeda in the scaled model, showing your steps and using the appropriate units.
- By comparing the relative scaled distances between Sun and Proxima Centauri (in Part I) and between the Milky Way and Andromeda (in Part III), can you draw any conclusion about the probability of collision between stars and between galaxies? Are they both likely or unlikely? Explain.