How on Earth did they Find It?
30 April 2007Just briefly, in a previous post, I mentioned HARPS (High Accuracy Radial velocity Planet Searcher), the instrument used to first detect the presence of Gliese 581c. Detecting the presence of a star in a distant galaxy requires enough technology as it is, but finding a planet around a star is quite a chore! Here's a excerpt from an American.com article titled "What a New, Earth-like Planet Could Mean"…
"The particular High Accuracy Radial velocity Planet Searcher (HARPS) instrument used by the La Silla team detected velocity variations corresponding to about 9 km/hr—the speed of a person walking—from 120 trillion miles away." http://www.american.com/archive/2007/april-0407/what-a-new-earth-like-planet-could-mean
Despite the sensitivty of such an instrument, the true size of the planet will remain unknown until scientists can catch a glimse of Gliese 581c as it passes in front of Gliese 581 (the red dwarf star of Gliese 581c). The size of the shadow will enable scientists to more accurately calculate the size of the planet.
Another baffling idea: Every observation of the star is of its state over 20 years ago….that's the time it takes for light to reach Earth from Gliese 581c. As the American.com article mentions, if "inhabitants" of Gliese 581c were monitoring radio wave transmissions from Earth, they would just now be watching our TV shows from the 1980s….
No comments yet
Leave a Reply
You must be logged in to post a comment.