The phrase "planet form" means how a planet comes into existence or is created.
Sentences with «planet form»
This information can provide insight into where and how planets form around these stars, and how such stars evolve. (astronomynow.com)
This makes it a perfect laboratory to study how many planets form in such a crowded environment. (sciencedaily.com)
Third, the mechanisms by which planets form around stars are fairly well understood, and it would be surprising if they did not form. (tamino.wordpress.com)