# Our solar system is an abberant freak **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [May 7, 2013, 6:15pm UTC](https://boards.straightdope.com/t/our-solar-system-is-an-abberant-freak/657725 "2013-05-07T18:15:38Z")\ **Posts on this page:** 9\ **Page:** 2
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [May 11, 2013, 5:20pm UTC](https://boards.straightdope.com/t/our-solar-system-is-an-abberant-freak/657725/21 "2013-05-11T17:20:17Z")
> [@Sofis](#): > > The difference is that three is a useless sample size, while several hundred is not. The point is that the total number of stars in the galaxy (or universe) does not determine whether or not the hundreds of stars examined is sufficiently large. > If you were to somehow randomly select 637 apples (with every apple in the world being equally likely to be selected, somehow), and all of them were red, “all or almost all apples are red” would be a perfectly valid conclusion, and it would remain valid whether the total number of apples in the world were 100 000 or 100 000 000 000 000 000 000 000 000. Wrong again. You are defining the actual bias here though. The planets we’ve found weren’t selected with all possible planets being equally likely to be selected. ---
**Author:** ![Boyo\_Jim](https://avatars.discourse-cdn.com/v4/letter/b/87869e/32.png) [@Boyo\_Jim](https://boards.straightdope.com/u/Boyo_Jim)\ **Post date:** [May 11, 2013, 5:35pm UTC](https://boards.straightdope.com/t/our-solar-system-is-an-abberant-freak/657725/22 "2013-05-11T17:35:34Z")
> [@TriPolar](#): > > Wrong again. You are defining the actual bias here though. The planets we’ve found weren’t selected with all possible planets being equally likely to be selected. No, I don’t think so. Yes, it’s true that not all stars are equally likely to be selected. And that is a problem of sample bias, NOT sample size. From my reading, this is exactly what Sofis is saying. I have heard it claimed that a sample size in the neighborhood of a thousand, assuming it is a genuinely random sample, will be valid for any size population. I don’t know enough about stats, though, to say whether that really does hold true with a population that approaches infinity. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [May 11, 2013, 5:39pm UTC](https://boards.straightdope.com/t/our-solar-system-is-an-abberant-freak/657725/23 "2013-05-11T17:39:25Z")
> [@Boyo\_Jim](#): > > No, I don’t think so. Yes, it’s true that not all stars are equally likely to be selected. And that is a problem of sample bias, NOT sample size. From my reading, this is exactly what Sofis is saying. > > I have heard it claimed that a sample size in the neighborhood of a thousand, assuming it is a genuinely random sample, will be valid for any size population. I don’t know enough about stats, though, to say whether that really does hold true with a population that approaches infinity. That’s what I said. I was saying that Lurker’s idea of bias hasn’t been established. Our detection process may turn out to be the best one there is. We don’t know though, because guess why? ---
**Author:** ![Boyo\_Jim](https://avatars.discourse-cdn.com/v4/letter/b/87869e/32.png) [@Boyo\_Jim](https://boards.straightdope.com/u/Boyo_Jim)\ **Post date:** [May 11, 2013, 5:42pm UTC](https://boards.straightdope.com/t/our-solar-system-is-an-abberant-freak/657725/24 "2013-05-11T17:42:50Z")
Then why are you quoting **Sofis** and saying “Wrong again”? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [May 11, 2013, 5:59pm UTC](https://boards.straightdope.com/t/our-solar-system-is-an-abberant-freak/657725/25 "2013-05-11T17:59:25Z")
> [@Boyo\_Jim](#): > > Then why are you quoting **Sofis** and saying “Wrong again”? Sorry, I am being confusing. Sofis is right about sample size not mattering, if there is no bias. But the post I was responding to made the assumption of unbiased selection. I was saying that Sofis defined the bias, not the reason the sample size was sufficient. So Sofis is right that if unbiased the sample size isn’t affected by the total number of possible planets. I apologize **Sofis** for poorly wording in that way. I should have just pointed out the distinctions. ---
**Author:** ![coremelt](https://avatars.discourse-cdn.com/v4/letter/c/4491bb/32.png) [@coremelt](https://boards.straightdope.com/u/coremelt)\ **Post date:** [May 11, 2013, 6:27pm UTC](https://boards.straightdope.com/t/our-solar-system-is-an-abberant-freak/657725/26 "2013-05-11T18:27:25Z")
This thread is missing some perspective . There is 300 billion stars in our galaxy . If one in one million star systems has a solar system like ours then there is 300,000 in our galaxy. Maybe we are a freak but we still have company . ---
**Author:** ![Uber\_the\_Goober](https://avatars.discourse-cdn.com/v4/letter/u/58956e/32.png) [@Uber\_the\_Goober](https://boards.straightdope.com/u/Uber_the_Goober)\ **Post date:** [May 11, 2013, 7:13pm UTC](https://boards.straightdope.com/t/our-solar-system-is-an-abberant-freak/657725/27 "2013-05-11T19:13:08Z")
> [@TriPolar](#): > > Utter nonsense in this case. We have no idea what the size of the population is, or even the possible conditions where earth like planets could occur. There’s no sampling going on, the samples are the only planets we know about. It’s not sampling, it’s mindless extrapolation. [Extrapolation is FUN](http://m.xkcd.com/605/) ---
**Author:** ![Malacandra](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Malacandra](https://boards.straightdope.com/u/Malacandra)\ **Post date:** [May 12, 2013, 7:24am UTC](https://boards.straightdope.com/t/our-solar-system-is-an-abberant-freak/657725/28 "2013-05-12T07:24:31Z")
> [@coremelt](#): > > This thread is missing some perspective . There is 300 billion stars in our galaxy . If one in one million star systems has a solar system like ours then there is 300,000 in our galaxy. Maybe we are a freak but we still have company . It’s that word “if”, though. Until we have far superior means of detecting exoplanets like ours we haven’t a clue if one in one million is a reasonable estimate. (Among other things, it’ll be hard to probe a million star systems.) And even if it is, that strains the definition of “company” a little. 😃 ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [May 12, 2013, 3:29pm UTC](https://boards.straightdope.com/t/our-solar-system-is-an-abberant-freak/657725/29 "2013-05-12T15:29:01Z")
> [@TriPolar](#): > > Right. Like Earth 2 that orbits on opposite side of the sun from us. To be fair, the only reason we cannot detect it is because it is made from dark matter. [Previous page](https://boards.straightdope.com/t/our-solar-system-is-an-abberant-freak/657725.md?page=1)