Question

I just watched ESB again (kickass movie), but Sidious tells Vader that "The Son of Skywalker cannot become a Jedi."

So, my question is, how did Sidious find out that Vader had kids? I thought he wasn't aware of it in RotS.

No replies? Unlucky!

After the blowing up of the Death Star, the name "Luke Skywalker" was all around the Galaxy. Sidious must have thought it was strange that someone with the last name "Skywalker" was an insanely skilled pilot who nearly did the impossible. He put two and two together and deduced that he must have been Anakin's son.

Or, Vader told him that Padme was pregnant and that she, and her son died. When Palpatine heard the news, he must have realized that the son survived.

That, or he just felt it through the force.

Originally posted by Generic Hero
After the blowing up of the Death Star, the name "Luke Skywalker" was all around the Galaxy. Sidious must have thought it was strange that someone with the last name "Skywalker" was an insanely skilled pilot who nearly did the impossible. He put two and two together and deduced that he must have been Anakin's son.

Or, Vader told him that Padme was pregnant and that she, and her son died. When Palpatine heard the news, he must have realized that the son survived.

That, or he just felt it through the force.

So, no official explanation?

Originally posted by Generic Hero
After the blowing up of the Death Star, the name "Luke Skywalker" was all around the Galaxy. Sidious must have thought it was strange that someone with the last name "Skywalker" was an insanely skilled pilot who nearly did the impossible. He put two and two together and deduced that he must have been Anakin's son.

That's pretty much it, yes. As Generic Hero said, the name Skywalker was being flung around a lot as the hero of the Alliance. The Emperor and Vader could have gotten the name from anywhere...