The Nourasians are perhaps the most humanlike species in the galaxy. The most obvious difference is the shape and length of their ears, which are pointed and slant downward. The King of Nourasia has particularly long ears, possibly due to old age. They also have reddish brown skin and blue eyes. Young Nourasians like Prince Aikka have orange hair, but like humans it turns gray with old age, as seen with Canaan.
Another major difference is their aging process, which is first hinted at when Molly meets Prince Aikka in Hostilities Break Out. When Aikka comments that Molly is too young to be "running around without parental guidance," Molly, who is 15 years old, becomes defensive and says "Where are your parents? You're no older than I am." Aikka's reply, "Well, in Earth years, perhaps," implies that although he may look like a human teenager, his true age is something else.
In The Art of Ōban Star-Racers, more specific detail is given about the aging process of Nourasians. One year on Nourasia is roughly 2.5 Earth years, so if a young Nourasian like Aikka is 15 years old at home, he would be about 37.5 Earth years old. Conversely, if he were 15 years old on Earth, he would be 6 Nourasian years old. In short, Nourasians age more slowly and can live much longer than humans.
The Nourasian people do not seem to possess any form of advanced technology as the two most frequently seen Nourasians have never been witnessed using it. However, it is made apparent that the Nourasians possess magical abilities as Prince Aikka demonstrates repeatedly throughout the series. The incantations also hint at a language other than whatever the Humans may speak as Aikka has been heard saying, "Uhm sakai G'dar' challenar." The name of his beetle remains unchanged in this example which only further proves that point.
It is made apparent that the Nourasians, despite not having advanced technology, have been in contact with humans as Jordan C. Wilde recognized Aikka as a Nourasian during episode 2. However, the lack of Nourasian technology and their alliance with hostile Crogs would make the human-Nourasian contact very limited.