Numbers_Activity_2020 (1).docx - Your Name: TA: Group...

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Astronomy 1101
Units, Numbers, & Proportions Activity
Part 1: Units
We use a lot of units in Astronomy and it is good to learn prefixes that go with them. Write down
using powers of ten the number of meters in each of the following units.
1. Kilometer -
2. Megameter -
3. Gigameter –
4. Nanometer -
Part 2: Estimation using Powers of 10 (No Calculators!)
This problem should help you get some idea for distance scales ranging from interplanetary to
interstellar and beyond. Estimate your answers using powers of 10 without using a calculator, and
please show all of your work.
5. The Earth is 150 million km (1 AU) away from the Sun. The diameter of the Sun is
1.4 Million km. How many Suns would have to line up side-by-side to reach from the Sun
to the Earth?
6. The nearest star is 250,000 AU away from our solar system. How many Suns would you
have to line up side-by-side to reach from here to the nearest star?
7. Our home galaxy, The Milky Way, is about 30,000 parsecs across. The nearest big galaxy,
Andromeda, is about 700,000 parsecs away. How many galaxies the size of the Milky Way
would fit in the space between our galaxy and Andromeda.
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8. Compare your answers to those for the previous two questions. What can you say about the
relation between the sizes of stars and the distances between stars, compared to the relation