If this is a physics riddle the string possibly does not exist.
If this is a religious riddle, the answer is god.
If you wish to have more responses, ask a question that makes sense.
For a question to be a good question it must have at least one correct answer and make sense. Your question does not make sense, therefore it is a bad question.
You're right, there's no such thing as a stupid question, just stupid people.
Half it's length doubled.
Its as long as your imagination will allow.
And if your a guy....... Take an Inch off. :)