system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Can terrestrial planets get as big as Jupiter? Or can they only get so big?
gpt
Terrestrial planets can't get much larger than 5-10 times the mass of the earth.

As a planet becomes bigger, its gravity increases, and it is able to retain a larger, thicker atmosphere.  After a point, that atmosphere becomes so thick, that planet is mostly atmosphere, and it becomes more Neptune like and less Earth like.