# Extrasolar Terrestrial Planet Discovered Orbiting mu Arae **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [August 25, 2004, 6:59pm UTC](https://boards.straightdope.com/t/extrasolar-terrestrial-planet-discovered-orbiting-mu-arae/261487 "2004-08-25T18:59:52Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![Ephemera](https://avatars.discourse-cdn.com/v4/letter/e/8baadc/32.png) [@Ephemera](https://boards.straightdope.com/u/Ephemera)\ **Post date:** [August 25, 2004, 6:59pm UTC](https://boards.straightdope.com/t/extrasolar-terrestrial-planet-discovered-orbiting-mu-arae/261487/1 "2004-08-25T18:59:52Z")
I expected to see a thread by \*\*Tuckerfan \*\* on this but after a quick scan, I didn’t find anything. > [@](#): > > …The so-far unnamed world, which whizzes around mu Arae in just 9.5 days, is the smallest of the estimated 125 so-called extrasolar planets that have been detected so far. > “This new planet appears to be the smallest yet discovered around a star other than the Sun. This makes mu Arae a very exciting planetary system,” French astronomer Francois Bouchy was quoted in a statement issued by the European Southern Observatory (ESO)… [http://story.news.yahoo.com/news?tmpl=story&u=/afp/20040825/sc\_afp/space\_astronomy\_planets](http://story.news.yahoo.com/news?tmpl=story&u=/afp/20040825/sc_afp/space_astronomy_planets) It’s discoveries like this that make me thrilled to be living in this day and age. ---
**Author:** ![PussyCow](https://avatars.discourse-cdn.com/v4/letter/p/22d042/32.png) [@PussyCow](https://boards.straightdope.com/u/PussyCow)\ **Post date:** [August 25, 2004, 7:13pm UTC](https://boards.straightdope.com/t/extrasolar-terrestrial-planet-discovered-orbiting-mu-arae/261487/2 "2004-08-25T19:13:35Z")
Ok, first of all, from what I understand of extrasolar planet searching, it’s based on detecting the wobble of the star due to the planet that is circling it. This would be dependent on the mass of the planet. So I see no problem with saying that the planet is 14 times the mass of the Earth, but how would they know it’s terrestrial? Unless there is a new way of detecting I’m not hip on. Also this is rather confusing: In one place they state: > [@](#): > > The so-far unnamed world, which whizzes around mu Arae in just 9.5 days and later in the article: > [@](#): > > This world circles its star every 3.03 days Anyone care to explain? Did I misread? ---
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [August 25, 2004, 7:16pm UTC](https://boards.straightdope.com/t/extrasolar-terrestrial-planet-discovered-orbiting-mu-arae/261487/3 "2004-08-25T19:16:44Z")
Considering that Mu Arae is substantially brighter than our Sun, this planet must be so close to Mu Arae that I’m surprised the terrestrial matter can remain solid. It reminds me of that story from Sainte-Exupery’s _The Little Prince_, where a lamplighter was on a planet that did a complete rotation every minute. Every 30 seconds he had to say, “Bon nuit”, or “Bon matin” accordingly. Except here it’s “Bon annee” every nine days. Imagine having only eight shopping days till Christmas, at the beginning of the year. ---
**Author:** ![Mystery\_Dog](https://avatars.discourse-cdn.com/v4/letter/m/f14d63/32.png) [@Mystery\_Dog](https://boards.straightdope.com/u/Mystery_Dog)\ **Post date:** [August 25, 2004, 7:17pm UTC](https://boards.straightdope.com/t/extrasolar-terrestrial-planet-discovered-orbiting-mu-arae/261487/4 "2004-08-25T19:17:31Z")
Am I the only one who misread the thread title as “Extrasolar Terrestrial Planet Discovered Orbiting my Arse”? ---
**Author:** ![Spectre\_of\_Pithecanthropus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spectre_of_pithecanthropus/32/12343_2.png) [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)\ **Post date:** [August 25, 2004, 7:21pm UTC](https://boards.straightdope.com/t/extrasolar-terrestrial-planet-discovered-orbiting-mu-arae/261487/5 "2004-08-25T19:21:07Z")
> [@PussyCow](#): > > So I see no problem with saying that the planet is 14 times the mass of the Earth, but how would they know it’s terrestrial? Just a WAG, so take with a grain of salt, but I suspect a gas planet couldn’t exist with that mass. The gas planets in our own system are far, far bigger than that. Still, I thought any solid object orbiting too closely to another object of tremendous mass, as a star would be, would be torn apart by tidal forces. I’ll be interested to learn how it is that’s not happening here. ---
**Author:** ![Ethilrist](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ethilrist/32/4604_2.png) [@Ethilrist](https://boards.straightdope.com/u/Ethilrist)\ **Post date:** [August 25, 2004, 7:23pm UTC](https://boards.straightdope.com/t/extrasolar-terrestrial-planet-discovered-orbiting-mu-arae/261487/6 "2004-08-25T19:23:34Z")
**Mystery Dog** : No… no, you’re not. My reaction: It orbits your _what???_ Is this a TMI thread, or what? ---
**Author:** ![PussyCow](https://avatars.discourse-cdn.com/v4/letter/p/22d042/32.png) [@PussyCow](https://boards.straightdope.com/u/PussyCow)\ **Post date:** [August 25, 2004, 7:24pm UTC](https://boards.straightdope.com/t/extrasolar-terrestrial-planet-discovered-orbiting-mu-arae/261487/7 "2004-08-25T19:24:02Z")
> [@Spectre of Pithecanthropus](#): > > Just a WAG, so take with a grain of salt, but I suspect a gas planet couldn’t exist with that mass. The gas planets in our own system are far, far bigger than that. The article said it was the size of Uranus. However, I _did_ think Uranus is a bit bigger than 14 times the Earth. So is that another problem with the article? Honestly, was this written by _Weekly World News_? ---
**Author:** ![PussyCow](https://avatars.discourse-cdn.com/v4/letter/p/22d042/32.png) [@PussyCow](https://boards.straightdope.com/u/PussyCow)\ **Post date:** [August 25, 2004, 7:31pm UTC](https://boards.straightdope.com/t/extrasolar-terrestrial-planet-discovered-orbiting-mu-arae/261487/8 "2004-08-25T19:31:20Z")
Ok, found this through a google search. It appears Uranus is [4 times the size of Earth](http://www.windows.ucar.edu/tour/link=/our_solar_system/relative_size.html&edu=elem) and [14 times the mass of Earth](http://www.nps.gov/brca/Geodetect/Earth%20Systems/solar%20system%20size%20up.htm#uranus) ---
**Author:** ![Ephemera](https://avatars.discourse-cdn.com/v4/letter/e/8baadc/32.png) [@Ephemera](https://boards.straightdope.com/u/Ephemera)\ **Post date:** [August 25, 2004, 7:37pm UTC](https://boards.straightdope.com/t/extrasolar-terrestrial-planet-discovered-orbiting-mu-arae/261487/9 "2004-08-25T19:37:37Z")
While I have been told I have a huge ass, it’s not yet large enough to have its own gravity well. And after having the errors in the article pointed out to me (about the orbital period… the Uranus thing looks to only be a mixup between size and mass), I don’t know how to take the news. I just saw it and since I’m a huge space geek, had to share it. Guess I should have been less enthusiastic. 🙂 ---
**Author:** ![PussyCow](https://avatars.discourse-cdn.com/v4/letter/p/22d042/32.png) [@PussyCow](https://boards.straightdope.com/u/PussyCow)\ **Post date:** [August 25, 2004, 7:44pm UTC](https://boards.straightdope.com/t/extrasolar-terrestrial-planet-discovered-orbiting-mu-arae/261487/10 "2004-08-25T19:44:17Z")
> [@Aesiron](#): > > Guess I should have been less enthusiastic. 🙂 Oh no, **Aesiron**! Don’t get me wrong. I think it’s really great news! Finding more extrasolar planets is a wonderful thing. And finding one only 14 times the size of Earth is phenomenal! It shows our techniques are becoming refined and soon we may actually be detecting Earth-sized planets (although I think they’d have to use another method for locating ones this size as such a small mass and increased distance from the parent star would cause such an infinitesimally small wobble in said star). I was just nit-picking. Please be excited!! ---
**Author:** ![PussyCow](https://avatars.discourse-cdn.com/v4/letter/p/22d042/32.png) [@PussyCow](https://boards.straightdope.com/u/PussyCow)\ **Post date:** [August 25, 2004, 7:45pm UTC](https://boards.straightdope.com/t/extrasolar-terrestrial-planet-discovered-orbiting-mu-arae/261487/11 "2004-08-25T19:45:49Z")
> [@Aesiron](#): > > Guess I should have been less enthusiastic. 🙂 Oh no, **Aesiron**! Don’t get me wrong. I think it’s really great news! Finding more extrasolar planets is a wonderful thing. And finding one only 14 times the size of Earth is phenomenal! It shows our techniques are becoming refined and soon we may actually be detecting Earth-sized planets (although I think they’d have to use another method for locating ones this size as such a small mass and increased distance from the parent star would cause such an infinitesimally small wobble in said star). I was just nit-picking on how the article is written. It really goes to show how badly journalists understand what they write about even if they are supposed to be specialized in that field. I wouldn’t doubt that the journalist just screwed up the facts given her/him by the scientist. Please be excited!! ---
**Author:** ![dwyr](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dwyr/32/363_2.png) [@dwyr](https://boards.straightdope.com/u/dwyr)\ **Post date:** [August 25, 2004, 11:28pm UTC](https://boards.straightdope.com/t/extrasolar-terrestrial-planet-discovered-orbiting-mu-arae/261487/12 "2004-08-25T23:28:52Z")
The article is talking about two different planets that have been discovered recently. The first orbits around mu Arae in 9.5 days; the second is in the constellation Lyra and orbits in 3.03 days.