There are some who think that there are multiple universes. There are some who think that they have visited other universes. The latter have been the dupes of lying spirits who have given them powerful hallucinations of having travelled to other universes.
Are there other universes? There could be. God is immense and powerful beyond our ability to imagine, so it would not surprise me if there are other universes, but I don't think that we need to be concerned about them. He made us for this universe, and we haven't gotten very far in doing what we are supposed to be doing here, so there is no way that we are going to be doing any inter–universe travelling in our lifetimes. Maybe we will never travel to other universes, not even after we have been in Heaven for a zillion zillion years. I am fine with that.
Regardless if there are other universes, there is one thing we can know for a fact; there is only one God. Isaiah 43:10 says, "You are my witnesses, says the LORD, and my servant whom I have chosen: that you may know and believe me, and understand that I am he: before me there was no God formed, neither shall there be after me."
If there are other universes, it is good to know that God rules them, for He is pure Love, He is completely good, He is utterly holy, He knows all, He is all–wise, He is all–powerful, He is everywhere all at once, He owns everything, and He NEVER makes mistakes. It sure feels safe to know that He is in control.
It's vanity to imagine that one can travel to other universes, and folly to let satan and his angels mess around with one's mind. It's nothing more than pride that motivates people to seek those kind of experiences. Why would anyone think that God would let someone who is pathetically weak compared to the tiniest angel in Heaven travel to other universes? Or why would He let them travel to another universe when they are contaminated by sin, and would contaminate another universe, if they could go there? Only satan and his bunch would say otherwise. They must laugh like crazy in Hell when one of their astral travellers takes their last trip and ends up there.
We have plenty of things in this universe to keep us busy, like learning to love God with all our heart, mind, and strength, and to love our neighbours as ourselves. Some have trouble keeping up with washing their dishes, never mind taking the time to jaunt off around the galaxy and other dimensions. Until we have conquered everything in this life, including walking in absolutely perfect health, behaving totally loving towards others, and knowing everything there is to know about this universe, we aren't psychologically or spiritually equipped to travel to another universe.
Exploring other worlds can wait. My advice to those who want to do it, is stop messing around with satan, and run to Jesus. We need Him to help us get through this life and take us safely into the next. If we have been redeemed by the Blood of the Lamb, and have been faithful to Him to the end of our life, then we will get to do all sorts of fun stuff in Eternity. I am really looking forward to learning a lot about quantum physics and complex mathematics, and all sorts of things that are currently beyond my brain's capacity.
If you have been messing around with astral travel, call on the Lord to deliver you from the deceiving spirits who have been playing games with you. Isaiah 43:11 – 13 says, "I, even I, am the LORD; and beside me there is no saviour. I have declared, and have saved, and I have shown, when there was no strange god among you: therefore you are my witnesses, says the LORD, that I am God. Yes, before the day was I am he; and there is none that can deliver out of my hand: I will work, and who shall prevent it?" It's not a good idea to set oneself up against God, but it sure is a good idea to go over to His side and stay there.
Romans 10:12 – 13 says, "For there is no difference between the Jew and the Greek: for the same Lord over all is rich unto all that call upon him. For whosoever shall call upon the name of the Lord shall be saved." Did you see what it says just before the last verse? It says He is RICH towards all who call upon Him. He wants to deliver us from bondage and give us abundant life, not have us limp through life as spiritual cripples.
Psalm 107:17 – 20 says, "Fools because of their transgression, and because of their iniquities, are afflicted. Their soul abhors all manner of meat; and they draw near unto the gates of death. Then they cry unto the LORD in their trouble, and he saves them out of their distresses; He sent his word, and healed them, and delivered them from their destructions."
Call upon the Lord. His Name is Jesus, or Yehoshua/Yeshua in Hebrew. It doesn't matter if we call upon Jesus in Nazareth in English, Spanish, French, whatever – He knows His Name and He responds to sincere cries from souls who want to be cleansed from sin and freed from its damaging effects upon their psyche.
The Universe resists the perverse,
But it opens its arms to the meek.
If its broad realms you wish to traverse;
First its Maker you must seek.
Otherwise, you silly guys,
You will walk into a snare.
For the spirit guides, whose wisdom you prize,
Are treacherously leading you to their lair.
Yeah, they are dropping their crumbs, making all sorts of promises about goodies in the afterlife, but they don't have any intention of keeping those promises, nor do they have any ability to make good on them, even if they would. The Lake of Fire awaits them and they want to take as many souls with them as they can because they hate God, who loves us, and they are jealous of humans, who have the potential to reign with Jesus over all the other angels, if we will accept His redemption and walk in His ways.
Your word have I hid in my heart, that I might not sin against you.