time travel paradox
solution: multiverse
answer: in a multiverse basically everything would be possible, the different timeline you went back too could/would develop completely differently then your original timeline. so might be possible you went back in time and btc will be worthless after you bought alot
This
If you travel back in time, you will change the randomness of the network and cause the blockchain to be totally different than the blockchain that we know today
The world will just fork into another reality that is unrelated to the reality you know today
Actually I don't believe the multiverse theory since it creates energy out of nothing when the world splits into two reality, and we all know that energy will just go down and entropy is getting higher and higher over time. So time travel is impossible at least in our universe