I think it’s incredibly fun to look at the scale of the universe in a sense we can understand. The D.C. Voyage model gives us a good sense of distance. What about the size of things? We can use compare fruit all we want, but all it’s doing is making me hungry.
Instead, I’d recommend checking out this video produced by the Russian Federal Space Agency. We can see the size of some of the more familiar stars if they were at the same distance as our sun. If you can read Cyrillic, you should get a sense of what we’re looking at. Otherwise, turn on closed captioning or reference below. I’ve also included the sizes of the stars if you’re interested in the numbers.
- [Альфа-Центавра] Alpha Centauri – 1.2 R☉
- [Сириус] Sirius – 1.7 R☉
- [Арктур] Arcturus – 25 R☉
- [Вега] Vega – 2.8 R☉
- [Полярная звезда] Polaris – 46 R☉
Source: Телестудия Роскосмоса
Just remember that these are size representations, not luminosity. We wouldn’t be able to see much of anything if they were scaled to luminosity at this distance. One of these stars is over 2000 times brighter than the sun!
Cherie's Astro Blog 
The size of Polaris totally surprised me. A question I’m pondering is: would any of these stars swallow up the planets closer to our sun? And as an add on to that question: Any stars out there that you know of that would swallow up the Earth if it were to suddenly replace the sun?
Also, if you’re interested in stars, look a little deeper into Polaris and you’ll see that it is what’s called a Cepheid Variable. These types of stars are interesting because their unstable; they’re outer shell literally moves inward and outward in a periodic fashion, and the nature of that motion is directly related to its luminosity. Interestingly, by measuring the periods and brightness of stars like these, we can find their distances. This was the original experimental basis for Hubble’s Law; it’s amazing what the smallest details of stars will tell us!
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Wow that video is pretty amazing. How cool would that be! They are huge!
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Grader comments: Its great that you reminded your readers that radius doesn’t imply anything about the star’s brightness as observed from Earth. Sirius is the brightest star in our night sky, and Polaris is actually pretty faint!
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