Fellow speaker,
To make sure you are pausing long enough for your audience after asking a deep, thoughtful question, pause until you are very uncomfortable. If you simply pause until you are uncomfortable and then speak, then most likely you have a short pause that the audience will hardly notice. If, instead, you pause until you are very uncomfortable, you will have a much longer, emotional pause that the audience will pay attention to and use to answer your question in their mind.
Pausing to pause,
Tim