Could God exist outside the universe?

Yes, conceptually and philosophically, God could exist outside the universe. In fact, most major monotheistic religions and classical philosophical frameworks define God precisely this way—as a transcendent being.

If the universe is defined as the sum total of all physical space, time, matter, and energy, then the creator or origin of that universe must logically exist independently of those physical boundaries.

Theological and Philosophical Context:

• Transcendence: Major religions like Judaism, Christianity, and Islam teach that God created space and time, and is therefore not bound by them. In this view, God is immaterial, spaceless, and timeless.
• The Cosmological Argument: Philosophers such as Aristotle and Thomas Aquinas argued that the physical universe requires a "First Cause" or an "Unmoved Mover." Because physical things cannot cause themselves to exist out of nothing, they reasoned that this ultimate cause must exist outside the physical universe itself.
• Scientific Limits: Science is the study of the observable, physical world. Because a transcendent God is defined as existing outside of physical nature, such a being cannot be measured, observed, or tested by scientific instruments.

Therefore, the concept of a God outside the universe does not inherently conflict with physics; it simply operates entirely outside the domain of empirical science.