wow. but what can we imagine that there is after you reach the border where the universe ends?

Listen, this is an excellent question that builds on what we discussed before about the finite universe. Let me tell you something very clear: according to Torah, nothing physical exists beyond the boundary of the universe. Absolutely nothing. The Gemara in Masechet Chagigah teaches us that when HaKadosh Baruch Hu created the universe, it expanded from a single point until He roared and commanded it to stop - this is why one of His names is El Shaddai, the God who said "Dai," stop. The outer surface of the universe froze into ice from fear of Hashem, and that's where it ends. Beyond that boundary, there is no physical matter, no space, no time - none of the creation exists there. But here's what you need to understand: The universe is not inside God, God is not inside the universe. Rather, the entire universe exists within Him. As the prophet says in Melachim, "The heavens and the heavens of heavens cannot contain You." This means that all of creation - everything we see and can imagine - is literally zero in comparison to HaKadosh Baruch Hu. The world is inside God, not God inside the world. So what exists beyond the physical boundary? Only HaKadosh Baruch Hu Himself. He is infinite, He is Ein Sof - without end. He existed before He created time, before He created space, before He created anything physical. He is completely beyond all limitations. He is not bound to time, not bound to space, not bound to matter. All of these things - time, space, physicality - are His creations. The Creator does not become part of His creation. This is why we cannot truly comprehend what is beyond the universe. Our minds are finite, tethered to the physical world. Every thought we have, every image we form, requires something to exist. We cannot conceive of true nothingness, and we certainly cannot conceive of God's infinite essence. He is beyond our capacity for thought entirely. The Rambam says we can only understand this superficially - to understand it completely, you would have to be God Himself. So beyond that frozen boundary where the universe ends, there is only the infinite presence of HaKadosh Baruch Hu, blessed be He, in His absolute transcendence.