Hi, John. No, humans (and other humanoids) live throughout the galaxy. The Nordics are a major part of them. Earth is a "Goldilocks planet," not too hot, not too cold, but just right, which has attracted war/catastrophe refugees and colonists for tens of thousands of years. This is why we have different human races here, and also conflict. Most areas (planets) are settled by one race only. Diversity is seen as an unsolvable problem everywhere.
The various humans and other humanoids live IN planets, not on them, just as we do not live on the roof of our houses, but down inside them. Thus they avoid the effects of earthquakes, hurricanes, tornadoes, blistering heat, snowstorms, slippery ice (I fell four times on treacherous sidewalk ice last winter despite taking every precaution), not to mention comets and asteroids which can wipe out 90% of all life on a planet, an ELE, an Extinction Level Event!
The exception is the Middle East, where during the summertime people commonly sleep on the flat roof for coolness. When Jesus spoke of people shouting from the rooftops, that is what he referred to.
Advanced civIlizations grow crops under excellent artificial light inside planets and grown meat in petri dishes. Most planets in our solar system are inhabited. This is why when benighted and savage earthlings edge closer to a full-scale nuclear war, our neighbors take strong exception to it. It causes damage to them inside their planets.
So, yes, there are Martians, Venusians, Saturnians, etc. When NASA spouts that no one can live on the surface of those planets, with their heat, cold and toxic gases, they are right, and telling the truth, but a half-truth.