# The Little Dipper From Another Angle **URL:** \ **Category:** Factual Questions\ **Created:** [January 15, 2014, 7:12am UTC](https://boards.straightdope.com/t/the-little-dipper-from-another-angle/678858 "2014-01-15T07:12:41Z")\ **Posts on this page:** 7\ **Page:** 2
**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:** [January 15, 2014, 9:10pm UTC](https://boards.straightdope.com/t/the-little-dipper-from-another-angle/678858/21 "2014-01-15T21:10:09Z")
> [@](#): > > Figuring absolute magnitude based on the star’s spectrum and comparing that with the star’s apparent brightness? This is called “main sequence fitting”, and is the most generally-available method. There are many other methods which are usable in some circumstance or another, though: Many variable stars (not just Cepheids) can be determined from their periods; stars in clusters can be determined by any method of any star in the cluster, plus statistically from their proper motion (this is called the Moving Cluster method); there are other parallax methods available for some binary systems (especially if they’re resolvable or eclipse); and so on. ---
**Author:** ![Earl\_Snake-Hips\_Tucker](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/earl_snake-hips_tucker/32/3269_2.png) [@Earl\_Snake-Hips\_Tucker](https://boards.straightdope.com/u/Earl_Snake-Hips_Tucker)\ **Post date:** [January 15, 2014, 9:49pm UTC](https://boards.straightdope.com/t/the-little-dipper-from-another-angle/678858/22 "2014-01-15T21:49:29Z")
> [@Colibri](#): > > Here’s a [series of images of the Big Dipper](http://www.astro.cornell.edu/academics/courses/astro201/big_dipper.htm) from 100,000 years ago to 100,000 years in the future. . . . The Diamondback and the Wheelbarrow! ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [January 15, 2014, 9:50pm UTC](https://boards.straightdope.com/t/the-little-dipper-from-another-angle/678858/23 "2014-01-15T21:50:39Z")
> [@Zeldar](#): > > This has almost nothing directly to do with the OP question, but when my kids were little, grammar school age, I tried to impress them with the relative sizes and distances of the Solar System by converting things to the scale of our house being taken as the size of the Sun and then the planets to things like a basketball, a softball, a BB, and such at distances from our house that they could relate to. The nearby planets were on our block somewhere and the distant ones miles from home. > > Once that conversion was done it was difficult, even for me, to see how Gravity could bind such tiny things at such distances together as a “system.” To add to the fun, the nearest star (at that scale) would have been in Australia. You must have a tiny house, or I must have done something wrong, because using the scale of basketball:Earth as a starting point I calculated the Moon to be a tennisball 7 meters away, the Sun to have a diameter of 26 m 2,8 km away, and Proxima Centauri to be twice the distance of the actual Moon. ---
**Author:** ![Zeldar](https://avatars.discourse-cdn.com/v4/letter/z/b77776/32.png) [@Zeldar](https://boards.straightdope.com/u/Zeldar)\ **Post date:** [January 15, 2014, 10:13pm UTC](https://boards.straightdope.com/t/the-little-dipper-from-another-angle/678858/24 "2014-01-15T22:13:55Z")
> [@naita](#): > > You must have a tiny house, or I must have done something wrong, because using the scale of basketball:Earth as a starting point I calculated the Moon to be a tennisball 7 meters away, the Sun to have a diameter of 26 m 2,8 km away, and Proxima Centauri to be twice the distance of the actual Moon. As best I can recall the inner planets were much smaller and the basketball might have been Jupiter. And it just might have been Pluto (which was still considered a planet nack then) that was in Australia. I’d try to reconstruct the “system” I came up with back then (early 70’s) but I thought the comments were already a near hijack to the thread. It was mostly to suggest setting up some miniaturized analogy to the stars in the Little Dipper to be able to get a sense of how far apart and how far away they are from each other. ---
**Author:** ![K364](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/k364/32/5_2.png) [@K364](https://boards.straightdope.com/u/K364)\ **Post date:** [January 15, 2014, 11:23pm UTC](https://boards.straightdope.com/t/the-little-dipper-from-another-angle/678858/25 "2014-01-15T23:23:01Z")
> [@Colophon](#): > > This raises an interesting possibility. Given a 3D map of the stars in our Galaxy and some pattern-recognition software, I wonder if a computer could “fly around” and find a vantage point where the stars form a passable portrait of, say, Justin Bieber? 🙂 That constellation would be called the “Little Dips\*\*t” ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [January 16, 2014, 9:26am UTC](https://boards.straightdope.com/t/the-little-dipper-from-another-angle/678858/26 "2014-01-16T09:26:52Z")
The stars of Ursa Minor have a spread of depth of 400 ly . If they were all at 50 ly, they’d be only a few ly apart… SO its more of a long chain … like a straight line … the bumps and wobbles in that chain would hardly be noticable. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [January 17, 2014, 11:21am UTC](https://boards.straightdope.com/t/the-little-dipper-from-another-angle/678858/27 "2014-01-17T11:21:01Z")
> [@chrisk](#): > > Yeah, that’s about the threshold where the parallax is relatively easy to detect, right? Ground-based parallaxes are good out to about 300 ly. They can measure beyond that, but the error bars become largish. The Hiparchos spacecraft was meant to do a better job, and it did. But it had problems and its results were less good than expected. IIRC, it pushed out the well measured stars to 400-some ly, though. But only for relatively bright stars, as it had a fairly high limiting magnitude. Its successor, [the Gaia mission](http://en.wikipedia.org/wiki/Gaia_(spacecraft)) is expected to do much better. But it was just launched recently (last month, in fact), so it’s going to be a few years before we get any results. [Previous page](https://boards.straightdope.com/t/the-little-dipper-from-another-angle/678858.md?page=1)