I believe the Rambam or Ramban (i could be wrong about who said it) said that in the 6 millenium (the one we are currently living in) will be a time for great discoveries about the world and if the jews deserved it then it would be through them otherwise nonjews would discover them.
This should answer lesschumras’s first question.
Just because you have knowledge of something does not mean it can be done. I know that to make an atom bomb you need to split atoms. Even if I knew how to do that it does not mean I have the necessary equipment to do it. I hope this answer your second question.