Here is my observation of racism . Racism is a form of prejudice and our prejudices comes from our minds want to quickly classify and understand new things . If there was a town on the other river bank and there were a few people you met from that town who were assholes . your mind will likely think People from River Bank village are all assholes . In a similar yet different way . your mind does the same thing when it encounters people of similar physical characteristics . On Earth , the amount of melanin in your skin is the factor . However , in your world it could be ear shape . It could be pitch of voice . But I think that the distinction for racism is that its general based on physical features . I think there could be prejudices for nonearth borns . Spacers might be thought less of . I think to understand your world you have to rank your prejudices . Which is worse Being from a certain geographic location , have certain physical features , or being a nonEarther ?