What was the first country to fly a spacecraft ? -  The first country to fly into space was Russia.  The astronaut's name was Yuri Gagarin in 1961.
Are there any other planets in the galaxy? -  No there are not any other planets in our galaxy because Pluto is not a planet anymore.  
 Why isn't Pluto a planet ?- Pluto is not a planet anymore because it did not have the third rule to be considered a planet    .  It is now a dwarf planet.
Are there any other galaxies in space?- Yes, there are probably billions more galaxies in space that are very far away.  We live in the Milky Way galaxy.
Where did you get so much imformation? - I looked at books and did a lot of research online.