Is it possible for bitcoin to live on another network?

[findftp]

Can bitcoin for example live on another physical network completely disconnected from the internet we now know?
Let's say we bring bitcoin to a colony on mars and there is a latency free connection possible but it costs too much to have a connection live all the time.

Can we then just send the blockchain from mars to earth and visa versa just once in a year for example?
Or would the blockchain be broken?

My gut is saying it is possible, but it introduces a trust factor you should not want.
Blocks should be solved every 10 minutes, not every year.

Or do I miss something?

[cr1776]

There would be a huge fork, approximately 52595 blocks long (*) if only synched once per year.  Then once it was sent, one fork would "win".  Without some protocol changes reconciling the two forks would cause havoc - one would lose.  :-)

Perhaps you could run it as some type of pegged side chain where the only time the networks would have to sync would be once a year or once a day - something where high latency would not be an issue. 

* [Very roughly ((525949 minutes/year / 10 minutes/block) * 1 year).]
* Just to note, the Mars - Earth distance varies between a bit over three minutes to just over 22 minutes so latency is definitely an issue there, but if there were a use case, I'm sure there could be a solution.

[spin]

I'm part of a private community run wifi based network.  Not exactly mars, but sometimes it feels like it

We have a few bitcoin nodes on this network and we have had some peer connections via this network.  We run on private ip space so some of the limitations of the core code is problematic.  It doesn't relay private ip addresses so we need to --addnode all connections on this ip space otherwise they do not work.  Connections aren't exactly stable either so tricky to maintain.  I've experimented with compiling a node that does relay private ips.  Got it running, but not sure I'd want others to run the tweaked core.

I've maintained my sync when my internet was down via this network.   All nodes also have internet though so bitcoin connecitons via this network is more of a curiosity and slight backup more than anything else.  

In terms of your example:

I guess the point is as long as one node is synced via normal means a private network could be up to date.  Networking code may need to be changed to allow nodes in this alternative network to relay info freely which each other.

I guess if you disconnect it should be ok for short periods of time.  However if you have miners on an alternate (smaller) network you could find blocks that will be invalidated when you reconnect to the larger network.  If you don't have miners I guess you'd be ok, but you'd be risking it as you might get miners that still mine and attempt double spends at the same time.  E.g. Look there's 3 confirmations give me my expensive item.  And then when the network reconnects you find that the coins were spent elsewhere.

edit: I also suspect the pegged sidechain might be a better solution for such a scenario, but don't know enough to comment.

[findftp]

I guess the point is as long as one node is synced via normal means a private network could be up to date.  

Yes, but only if everybody on the private network is absolutely sure that only that node is able to communicate with the largest network.
If one of the other nodes could communicate with the largest network he could seriously f*ck up your private network I could imagine.

[lolled]

Can bitcoin for example live on another physical network completely disconnected from the internet we now know?
Let's say we bring bitcoin to a colony on mars and there is a latency free connection possible but it costs too much to have a connection live all the time.

Can we then just send the blockchain from mars to earth and visa versa just once in a year for example?
Or would the blockchain be broken?

My gut is saying it is possible, but it introduces a trust factor you should not want.
Blocks should be solved every 10 minutes, not every year.

Or do I miss something?

I think it would cause forking and would simply be not possible.

[spin]

I guess the point is as long as one node is synced via normal means a private network could be up to date.  

Yes, but only if everybody on the private network is absolutely sure that only that node is able to communicate with the largest network.
If one of the other nodes could communicate with the largest network he could seriously f*ck up your private network I could imagine.

Yeah you'd need to trust the person running the connection.  I'd guess in the case of Mars you'd need to trust them in any case as it's likely the same person/organisation supplying oxygen, food etc.

[findftp]

I guess the point is as long as one node is synced via normal means a private network could be up to date.  

Yes, but only if everybody on the private network is absolutely sure that only that node is able to communicate with the largest network.
If one of the other nodes could communicate with the largest network he could seriously f*ck up your private network I could imagine.

Yeah you'd need to trust the person running the connection.  I'd guess in the case of Mars you'd need to trust them in any case as it's likely the same person/organisation supplying oxygen, food etc.

Indeed, that was one of the reasons why I chose that example and was talking about the trust factor.

[DannyHamilton]

I suspect the way to handle this would be for Mars to have it's own planetary crypto-currency (Marscoin?)  It would be identical to Bitcoin, except that it would have it's own Genesis block.  As such, local (Mars) transactions would all occur on Marscoin, and local (Earth) transactions would all occur on Bitcoin.

The only issue would be when someone on earth wants to send value to someone on Mars (or vice versa), since the two blockchains would be incompatible.

As such, there would be a cryptocurrency exchange that would allow users to convert bitcoins to marscoins and to convert marscoins to bitcoins.  You could then send your transaction via the high latency radio wave, and receive the first confirmation within an hour or so.  Is there really anything that you might pay for between planets that would need to be confirmed faster than that?  (interestingly, at maximum distance apart earth and mars radio waves would take 1337 seconds to travel between them (assuming that you could get the radio waves through the sun).

[findftp]

assuming that you could get the radio waves through the sun

I think the moments of an earth sun mars alignment are very very very rare and that they could be easily overcome by a using a proxy satellite in a delayed earth orbit around the sun. Just following earth orbit a few days/weeks/months behind. Or using another planet as a reflector to get the signal on mars (extra latency of course)
Offtopic, http://www.solarsystemscope.com/ is a nice website where you can easily see all planet orbits and drag them around.

[DannyHamilton]

I think the moments of an earth sun mars alignment are very very very rare

Perhaps.  I haven't looked into it.  However, when it happens direct communication between the planets will be cut off and longer/slower indirect paths will become necessary.

and that they could be easily overcome by a using a proxy satellite in a delayed earth orbit around the sun. Just following earth orbit a few days/weeks/months behind. Or using another planet as a reflector to get the signal on mars (extra latency of course)

Sure, but then the maximum delay will be longer than 1337 seconds.  That ruins all the fun.