3rd Rock From the Sun

A group of aliens is sent to Ohio to observe and research life on Earth. They take the form of a "typical" American family, and strive to assimilate into the culture around them. As high commander of the operation, Dick Solomon becomes the patriarch of their "human" family and teaches as a physics professor at the local university. There he becomes enamored of Dr. Mary Albright, with whom he shares an office and a secretary, Nina. Also posing as the Solomon family are Sally, a warrior alien in a sexy female body, Tommy, a wise elder alien in the form of a typical teenager and oddball Harry.