It's a rather controversial topic to discuss about. The thing about block interval is that the security of the network is taken into consideration. With a faster block, there is a risk that the propagation of the block within the network is too slow and that miners ends up mining a lot of orphans and causing more forks. Since Satoshi never publicly stated his rationale for the 10 minute block interval, it is widely assumed to be arbitary. Arguably, with better internet connection right now, the block interval can be lowered but there are still quite a few concerns.

The block interval of 10 minutes was probably simply a very conservative guesstimate.

Keep in mind Bitcoin was pioneering the field, it then took the first generation of alts to tinker with the basic parameters to see what works and what doesn't. Turns out Litecoin's block interval of 2.5 minutes works just as fine. Some alts reduced their block interval into the tens of seconds or even less with... not so good results. Orphan rate becomes a real problem at that time scale and needs to be dealt with (e.g. Ethereum paying subsidy for uncle blocks), otherwise your coin will be quickly forgotten.

Also you gotta think ahead a bit -- between Earth and Mars you have a data roundtrip time of 6 to 9 minutes!



That's just a sneaky way to increase blocksize