They were, of course, wrong. God can create any planet of any kind at any size He sees fit. We need no model of planetary formation to tell us that. It is my ardent hope that this discovery of a mystery of God's Creation -- one that illustrates that Man's science is and will forever be flawed and limited -- will convince these astronomers to abandon scientific inquiry and return to Faith in God Almighty.
There's one other thing I wanted to mention: As you can see in the Smithsonian Science article linked above, Dimitar Sasselov, one of the Harvard-Smithsonian Center for Astrophysics researchers involved in the project that detected Kepler-10c, says that "Kepler-10c has positive implications for life."
Now, I don't want to take away from Professor Sasselov's work here -- he has laid bare the fact that humanity cannot grasp the full wonder of God's Creation and so should simply abandon science, accept that God's Creation is wonderful, and focus on faithfully serving Him. But if he means that the existence of Mega-Earths like Kepler-10c suggests that there are more planets out there capable of supporting extraterrestrial life, he is flat wrong.
God created life once -- ONCE -- and He did it here on Earth. There is no other life in the Universe. All of the money you're funneling into astronomy, astrophysics, exobiology? That budget increase you just awarded NASA? It is all a waste of money. You're chasing things that don't exist when you should be focused on using that money to establish Christianity as your global religion, build churches, and exalt God.
Now that your science has served the limited purpose of disproving itself, it's time to pack it in, okay? No other beings will ever come down out of the sky to communicate with you.
Well, except for Jesus. And when that day comes, trust me: you'll be glad you accepted that scientific inquiry is heretical and returned to unquestioning faith in God.