The greatest truth for the universe and all humanity is God. He is -- he exists.
The first words of the entire Bible's Old Testament book of Genesis 1:1-2 begins with revealing and declaring God’s existence, especially as the Creator: "In the beginning God created the heavens and the earth. Now the earth was formless and empty, darkness was over the surface of the deep, and the Spirit of God was hovering over the waters."
One popular historical story in the Bible's Old Testament book of Exodus 3:14 similarly affirms his existence when God tells Moses what's the main reason the Egyptian Pharaoh is to release the enslaved Israelites, "God said to Moses, 'I AM WHO I AM.' And he said, 'Say this to the people of Israel: ‘I AM has sent me to you'." Later in history the Bible's New Testament records Jesus stating that he himself is the 'I Am:' "Jesus said to them, “Truly, truly, I say to you, before Abraham was, I am.”"
Jesus was then declaring himself as both being fully human and fully divine, and those that trust (faith in) him will be in relationship to God the Father, Son, and Spirit like the Bible's New Testament author of Hebrews 1:1-4 states: "In the past God spoke to our ancestors through the prophets at many times and in various ways, but in these last days he has spoken to us by his Son, whom he appointed heir of all things, and through whom also he made the universe. The Son is the radiance of God’s glory and the exact representation of his being, sustaining all things by his powerful word. After he had provided purification for sins, he sat down at the right hand of the Majesty in heaven. So he became as much superior to the angels as the name he has inherited is superior to theirs."
God purposely revealed himself to be known through creation and Christ, so that as we look up both, we wonder at him and his beauty regardless of the world's brokenness and beliefs. We then trust him:
Therefore, since we are surrounded by so great a cloud of witnesses, let us also lay aside every weight, and sin which clings so closely, and let us run with endurance the race that is set before us, looking to Jesus, the founder and perfecter of our faith, who for the joy that was set before him endured the cross, despising the shame, and is seated at the right hand of the throne of God. - Hebrews 12:1-2
“In whom [Jesus] we have redemption, the forgiveness of sins. He is the image of the invisible God, the firstborn of all creation.For by him all things were created, in heaven and on earth, visible and invisible, whether thrones or dominions or rulers or authorities—all things were created through him and for him.And he is before all things, and in him all things hold together.And he is the head of the body, the church. He is the beginning, the firstborn from the dead, that in everything he might be preeminent. For in him all the fullness of God was pleased to dwell, and through him to reconcile to himself all things, whether on earth or in heaven, making peace by the blood of his cross.” - Colossians 1:14–20
Nature even reveals that it is creation by a creator, confirming all that is said and done by God -- especially via Jesus' teachings read in the Bible's New Testament and using nature in parables and analogies. Many in our current times try like those in history to use nature or natural processes like logic, reason, or educational subject matters like science or math to disprove the existence of God. People might twist, replace, or mis-align truths, but it is actually by these truths that God uses to bring people to trust in him and the creator of the world and living word promised throughout history who came into real time for the world to believe in him -- Jesus the Christ:
For his invisible attributes, namely, his eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made. So they are without excuse. - Romans 1:20
Therefore, when we look through the history of God's world, we recognize Jesus as the epicenter and fully trustworthy.