Habitable Planets May Be Common

From the story:

Our own solar system and Milky Way galaxy are home to billions more planets than currently believed, greatly increasing the prospects of finding at least primitive forms of life out there.

Astronomers described new evidence here yesterday suggesting that anywhere between 20 and 60 per cent of all the sun-like stars in our local galaxy are good bets for forming so-called rocky planets, like Earth and Mars.

University of Arizona researcher Michael Meyer, who led the study, said he personally believes that more powerful telescopes will eventually reveal that every sun-like star "will have a rocky planet around it and the diversity of conditions on them will be huge."

Between 5 and 10 per cent of the 200 billion stars in the Milky Way galaxy are considered sun-like, depending on the strictness of the definition. That would still mean a minimum of 4 billion stars with rocky planets using the lowest percentages.

Its' refreshing to finally see empirical evidence catch up with what I long thought was a natural by-product of stellar formation.  When a star forms inside a stellar remnant of a previous supernova its gravity accretes the matter inside it's influence.  Over time, this orbital debris gravitates towards heavier bodies, forming larger and larger chunks with their own increasing amount of gravitational attraction.  Over time all the smaller debris falls into the remaining larger bodies, forming moons and if enough, rocky planets.

Depending on the amount of stellar debris, the amount of stars that form planets will vary in amount and size, but as this study suggests, it's between 20 to 60 percent of them.   If planets are this common, then the number and frequency of planets within a stars habitable zone increase tremendously.

The next question is how often does life form if conditions are right?  So far, the evidence seems to indicate that this is a relatively common occurrence too, as the basic building blocks of life are already existent in the stellar environment.