1. Evaluate the following expression:

2. Evaluate the following expression:

3. Let us play with the scale of the universe. Imagine that the solar system has been shrunk to the size of a dinner plate, i.e. the diameter of Pluto's orbit is now 20cm.
a. Look up the orbit of Pluto using the appendices of the textbook. By what factor has the orbit been reduced to become only 20cm across? i.e., give the number you calculate when you divide the diameter of Pluto's orbit by 20cm.  

b. At that scale how big is:
    i) a human?
    ii) the radius of the Earth?
    iii) the distance from the Earth to the Sun?
    iv) the distance to the nearest star?
    v) the distance to the center of the Milky Way?
    vi) the distance to the nearest galaxy (M31)?
    vii) the radius of the Universe?

Hint: Use information from the first two lectures and from the text to get  rough figures for the distances required.

4. NASA is currently has a mission en route to Pluto. For the spacecraft to reach its destination in seven years after launch, how fast must it travel?