6/29/2010.

Where did the physical matter that makes up the universe come from?

The question is meaningless. Since the universe is, by definition, all that exists, the question reduces to "where did all that exists come from." For something to "come from" something else, there must be something else. So to ask "where did everything that exists come from" is to ask "what is there other than all that exists."

If you literally mean where did the physical matter come from, likely it came from energy. But I presume that answer's not going to satisfy you. For every "where did X come from" question, and every answer "X came from Y," the next question will be "where did Y come from."

Most likely, the whole series of questions is meaningless. At 1 time, we didn't understand gravity and thought things just naturally fell down. People who ask "what holds the Earth up?" And for any answer "the Earth is resting on a turtle," you could follow up with "well, what holds the turtle up?" And, of course, the answer was that the original premise was wrong -- the Earth does fall.