這樣寫法有否出錯？

Without emphasis, the original sentence should look like this:
Until then, I did not know that the earth moves around the sun.
= Not until then, I knew that the earth moves around the sun.

"then" refers to some specific time in the past.

The best way to emphasize...by using it-cleft structure:
It was not until then that I (finally) knew that the earth moves around the sun.

2012-07-24 12:24:12 補充：
Practically speaking, the negative verb should be placed in the main clause.

e.g. I don't think (that) you are right.
NOT: I think (that) you are not right.

你的意思是否：在那時之前，我並不知地球繞著太陽轉。

你的句子文法未必錯，但總覺累贅，老外多會這樣寫

not until then did I know the earth moves around the sun.

用not until並用倒裝句，是老外常用，簡潔，有力，又青晰

希望幫到你！

你想要表達什麽意思?直到現在我依然不知道地球圍著太陽轉?