Jared Padalecki by Michael Muller/The CW; Tricia Helfer by Justin Stephens/Sci Fi Channel Jared Padalecki by Michael Muller/The CW; Tricia Helfer by Justin Stephens/Sci Fi Channel

What is it that makes sci-fi shows so appealing? Maybe it's because so many of the cast members are "out of this world" hot!

From Supernatural's Jared Padalecki to Battlestar Galactica's sexy cylon Tricia Helfer, there are plenty of sci-fi sexpots to choose from. So, we want to know: Who do you think are the sexiest sci-fi stars?

Share your picks in the comments below, and be sure to tell us why you think your choices are the hottest things on TV. Be sure to check back next week to see if your choice makes the list!