Bitcoin In Space
Bitcoin and space. When both are decentralized, they are natural allies.

I have been searching whether Bitcoins will work in space or not and come to know that there are people and organisations trying to do this but still, there are some problems for using Bitcoin as space currency. What possibly would be the currency in space? Dollars as we have here or Bitcoins are going to be used as currency in space? 

I don't think it's going to matter if you call the medium of exchange Bitcoin or dollars or little green apples. The difference is going to be the state of widely used fintech options are going to be by the time it even becomes an issue. Actually, you could just look at how long it sometimes takes to move money across national borders as things stand now to realize that it's going to be six of one and half a dozen of the other. It can take as long as six days for a fiat currency transaction to go from the U.S. to the Philippines, for instance, and I am not making this up. And this is a case in which the laws of physics are barely even a factor.

But isn’t decentralised currency better? Bitcoin is decentralised and any particular country or bank controls it. Or it doesn’t matter whether it’s centralised or decentralised? 

I'm pretty sure that Rocket Raccoon meant that the NAME doesn't matter. What matters is having a system that 1) Works and 2) Puts all participants on a more or less level playing field. Decentralization is preferable because then you won't get a situation where one colony (or planet) is jerking around with all the others. Everybody gets a vote without having to give up internal sovereignty. And if Bitcoin isn't quite ready to become the currency of choice right now, well, developers still have time to come up with improvements that will have it ready by the time it becomes an issue.

Now I got the idea what he meant to say. For now, we can say that the Cryptocurrency isn't that much mature to be used in space. It may become mature until we really get into space. 

Off course it's not going to take time for humans to colonise space and starting living in it.

I expect it will still take many, many more years before we can colonise space. I could be wrong, but we need faster means of space travel in order to explore more. By the time that we're ready to make space our home, the dollar will probably be no more. I'd actually be surprised if there would still be "paper money" 20 years from now, and the coins as we know them today will become collectors items.

I again have to agree with Rocketracoon here, we're really not that far advanced when it comes to currency. I have some personal experience with international money transfers, and it leaves much to be desired. (My bank agreed to accept an international transfer, when I didn't hear from them for 10 days and called, they said they couldn't handle international transfers, they had sent the money back and charged me $58 for the transfer back, true story)

Either way, I don't imagine someone carrying a wallet around in space and pulling out some twenty dollar bills. It won't happen. A digital currency like bitcoins makes a lot more sense.
Of course, we're not there yet, and who knows what will change between now and then. I do think that we're going to move more and more towards digital currency and leave the money as we know it behind us.