Claim:
Cosmologists can't explain where space, time, energy, and the laws of physics came from.
Response:
1. Some questions are harder to answer than others. But although we don't have a full understanding of the origin of the universe, we are not completely in the dark. We know, for example, that space comes from the expansion of the universe. The total energy of the universe may be zero. Cosmologists have hypotheses for the other questions that are consistent with observations [Hawking 2001]. For example, it is possible that there is more than one dimension of time, the other dimension being unbounded, so there is no overall origin of time. Another possibility is that the universe is in an eternal cycle without beginning or end. Each big bang might end in a big crunch to start a new cycle [Steinhardt and Turok 2002] or, at long intervals, our universe collides with a mirror universe, creating the universe anew [Seife 2002].
One should keep in mind that our experiences in everyday life are poor preparation for the extreme and bizarre conditions one encounters in cosmology. The stuff cosmologists deal with is very hard to understand. To reject it because of that, though, would be to retreat into the argument from incredulity.
2. Creationists can't explain origins at all. Saying "God did it" is not an explanation, because it is not tied to any objective evidence. It doesn't rule out any possibility, or even any impossibility. It does not address questions of "how?" and "why?", and it raises questions such as "which God?" and "how did God originate?" In the explaining game, cosmologists are far out in front.
References:
Hawking, Stephen, 2001. The Universe in a Nutshell. New York: Bantam.
Seife, Charles, 2002. Eternal-universe idea comes full circle. Science 296: 639.
Steinhardt, P. J. and N. Turok, 2002. A cyclic model of the universe. Science 296: 1436-1439.