# Diameter of milky way is 1.0 *10^5 light years

Tags:
1. Sep 6, 2004

### lilydaisy15

hey guys, i'm new to physics .. and to be frank it seems scary. :tongue:
anyways i was wondering if anyone could help me with this:
The diameter of milky way is 1.0 *10^5 lightyears (ly). The distance to Andromeda is about 2.0 million ly. If a scale model represents the milky ways and andromeda galaxies as dinner plates 25 cm in diameter, determine the distance between the two plates.

thanks you guys!!!

2. Sep 6, 2004

### arildno

The best way to overcoming your "fear" of physics is daring to express your own ideas!

So, what do YOU think is needed here?

3. Sep 6, 2004

### colinr

I'll give you a clue to start you off, there are about 10^16 metres per light year.

4. Sep 6, 2004

### HallsofIvy

I don't see how that helps at all!

lilydaisy15: your model is making 100000 ly correspond to 25 cm.
what would 2 million= 2000000 ly correspond to?

5. Sep 6, 2004

### colinr

well don't you need to know how many metres are in a light year before you can think about how many 25 cm are in 2 million light years

6. Sep 6, 2004

### colinr

well ok, you don't, but it is better to work in the same units for stuff like this when you're new to the subject