Planetary System Similar to Sol

sgtwilko writes "The BBC News site has an article about how astronomers have found several new planets including some that have a similar distribution to our own Solar System. They are finding planetary systems that are more and more like the one in which the Earth resides. It's only a matter of time until the Terrestrial Planet Finder program gets going and finds another Earth." There's another story on space.com. Update: 06/13 21:51 GMT by M : Space News and Wired have stories as well, with spiffy graphics and artists' renderings and so on.

Comments

Reason we can't detect planets the size of earth.

[Ami_Chan]

The article doesn't give much information about this, so I figured I'd put in my 2 cents from what I learned in astronomy this year:

Currently, they have 2 ways (that I'm familiar with) to find an extra-solar planet. First, they can look for a "wobble" in the path the star takes. This wobble is caused by the gravitational pull of a large planet orbiting the star. Earth is so small that the tiny wobble caused by a planet similar in size would be impossible to view; or at least it would disappear with the systematical error.

The other way I've heard of to find extra-solar planets is similar to an eclipse. When the planet comes between the star and Earth, we can measure the changes in luminosity of the star. Obviously, with planets with small orbits, we can determine how quickly the planet orbits the star because of the pattern in the luminosity. Again, we can't detect earth size planets since earth is just too small.

Didn't you read the article

[NoBeardPete]

The astronomers said that an Earthlike planet _could_ survive in an orbit between the two large ones. Given a choice between your guess that it would get ripped to shreds, and the opinions of professional astronomers who've studied this specific solar system, and concluded that an Earthlike planet could be there, I'm going to side with the astronomers.