The belt is thought to be from 30 to 50 million years old, and of unknown origin.

The universe is either open or filled with an energy of unknown origin.

It was joined by another G 10 of unknown origin, no. 57 4245.

Who would listen to what he had to say, a former slave of unknown origins?

However others simply say that the breed is "of unknown origin".

In 1903, a fire of unknown origin destroyed 17 businesses.

A spiritual of unknown origin which dates back to at least the 1870s.

He was married to Alberta, a woman, probably foreign, of unknown origin.

Five ships of unknown origin are there now, along with what seems to be a small black hole.

"There seem to have been electrical effects of an unknown origin," he said.