How many solar systems are there in our universe?
We now know of more than two hundred solar systems beyond our own. All of these are located within our own galaxy. It is very probable, based upon what we have discovered, that most stars are orbitted by planets–even binary stars. This would imply that our galaxy has more than 100 billion solar systems. Beyond our galaxy are another hundred billion galaxies. It is possible solar systems in globular clusters might be more rare than around stars in spiral galaxies, so this would reduce the number of solar systems in the universe. But that is not known.