Denise Chow, Space.com (February 2, 2011)
"The new discovery of six alien planets orbiting a sunlike star may be only a small part of the data released today (Feb. 2) from NASA's planet-hunting Kepler mission, but it is significant as the most tightly packed planetary arrangement around a single star yet discovered.
"The six planets orbiting Kepler-11 are all larger than Earth, with the largest ones comparable in size to Uranus and Neptune. As far as exoplanets go, these are relatively small worlds.
"Kepler-11 is located approximately 2,000 light-years from Earth. Astronomers used observations made by the Kepler spacecraft to detect the six planets that transit — pass in front of — the star....'
Fist of all, the Lemming - in a nit-picking mood - notes that we don't know (yet) if the Kepler-11 planets are "relatively small worlds" - "As far as exoplanets go." At this point, with fewer than a thousand expolanets - planets not orbiting Sol, our star - in the catalogs: We simply don't know what the 'typical' range of sizes is for planets in this galaxy.
Eventually, we'll have a large enough sample to be able to make educated guesses - but right now our detection methods work for large planets, and not so much for small ones like the one we live on. And that's almost another topic.
The Kepler 11 planetary system doesn't (as far as we can tell) have a planet that supports life. Or, rather, astronomers haven't spotted a planet there that's in the 'habitable zone' where water can exist on a planet's surface as a liquid.
Which may not be the only sort of place where life-as-we-know-it can exist. (January 26, 2011, March 24, 2010, May 12, 2010, March 5, 2009) Then there's life-as-we-don't-quite-know-it. (Drifting at the Edge of Time and Space ("April 12, 2010)
Back to the Kepler 11 system and its tightly-packed planets.
Five of the planets orbit Kepler 11 closer than Mercury does Sol. The sixth is closer than Venus is to our star.
Aside from the size of its planets' orbits, the Kepler 11 system is a bit like ours: all the planets orbit their star in roughly the same plane.
Studying them - and the hundreds of other expolanets - will help astronomers and cosmologists sort out the process(es) that produce planets. And, judging from what's happened in the last few thousand years of humanity's nosing about, raise new questions.
Frustrating? Not in the Lemming's opinion. "Exciting" is more like it.
- "Kepler-10b: Hot, Rocky, and the Smallest Exoplanet Yet"
(January 11, 2011)
- "Posts About the Gliese 581 Planetary System: Including Gliese 581g"
(October 14, 2010)
- "'More Than 100 Earth-Like Planets' Found? Well, No: Not Really"
(July 24, 2010)
- "Planets Found Circling Other Stars: 429 So Far"
(February 15, 2010)
- "Earth May Not Be a 'Class M' Planet"
(December 5, 2009)