# No scale model of the Solar System?

**URL:** <https://boards.straightdope.com/t/no-scale-model-of-the-solar-system/456773>\
**Category:** Factual Questions\
**Created:** [July 17, 2008, 1:09am UTC](https://boards.straightdope.com/t/no-scale-model-of-the-solar-system/456773 "2008-07-17T01:09:17Z")\
**Posts on this page:** 2\
**Page:** 3

<div class="post-metadata">

**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\
**Post date:** [July 31, 2008, 12:28am UTC](https://boards.straightdope.com/t/no-scale-model-of-the-solar-system/456773/41 "2008-07-31T00:28:03Z")

</div>

> [@](#):
>
> Here’s why it can’t be done. When you reduce all the lengths by a fraction, all the bodies’ volumes are reduced by the cube of that fraction, and therefore so are the masses. For example, in just a 1/2 scale model, the masses would decrease by 1/8. For this to work, you’d at least have to increase the density a lot. And you can see that’s a problem.

The masses would still all be in the right proportion, which is all you’d need. The time scale would, as **WarmNPrickly** suspected, be off, but it would be consistently off, so you could in fact speed up the film to make it right.

In actual practice, it wouldn’t even matter that much if the masses weren’t in the right proportion, so long as the Sun’s mass were much greater than anything else. Strictly speaking, everything orbits around the common center of mass, and the planets’ gravity affect each other, but that’s a small effect compared to the Sun’s.

---

<div class="post-metadata">

**Author:** ![mangeorge](https://avatars.discourse-cdn.com/v4/letter/m/d78d45/32.png) [@mangeorge](https://boards.straightdope.com/u/mangeorge)\
**Post date:** [July 31, 2008, 1:38am UTC](https://boards.straightdope.com/t/no-scale-model-of-the-solar-system/456773/42 "2008-07-31T01:38:10Z")

</div>

For the mass/volume to be correct, wouldn’t the models need to be made of pretty much the same materials as the bodies we’re modeling?  
That might be a problem for the Sun.

[Previous page](https://boards.straightdope.com/t/no-scale-model-of-the-solar-system/456773.md?page=2)