Hi, can someone help me? :)
In 1999 astronomers found evidence of six new planets orbiting distant stars, bringing to 28 the number of planets then known to exist OUT the solar system.

-why is out wrong?
-what is the meaning of then here? I mean, what is the function in the sentence?

Question

Hi, can someone help me? :)
 In 1999 astronomers found evidence of six new planets orbiting distant stars, bringing to 28 the number of planets then known to exist OUT the solar system.

-why is out wrong?
-what is the meaning of then here? I mean, what is the function in the sentence?

Answer

Instead of "out" it should be "outside of" (afuera del systema solar.)

then = at that point in time (entonces; en 1999)