In History there are events that happen by chance, but others not.
The colonization of the Americas is an event that happened when it was possible, not earlier or later (significatively).
Apart of the Norse, it's possible that other civilizations would manage to arrive to America before Columbus or even before the Norse (the fact that this is not documented doesn't imply that it didn't happen) but would have they been able to colonize or settle?
The Norse would never mixed with the Indian population like later European did, because it was simply difficult to accept for their culture. Of course, isolated cases could happen, but not at a significant scale.
Norse were not invaders in the sense of ruling foreign civilizations. They used to ransack them or occupying for a while, but did not create stable empires. They mostly settled inhabited (or almost) areas rather than populated ones.
The colonization of the Americas is an event that happened when it was possible, not earlier or later (significatively).
Apart of the Norse, it's possible that other civilizations would manage to arrive to America before Columbus or even before the Norse (the fact that this is not documented doesn't imply that it didn't happen) but would have they been able to colonize or settle?
The Norse would never mixed with the Indian population like later European did, because it was simply difficult to accept for their culture. Of course, isolated cases could happen, but not at a significant scale.
Norse were not invaders in the sense of ruling foreign civilizations. They used to ransack them or occupying for a while, but did not create stable empires. They mostly settled inhabited (or almost) areas rather than populated ones.