The astronomers have detected a planet 100 light-years away which resembles an infant version of Jupiter.
The new world, known as 51 Eridani b, is only 20 million years old-a toddler by astronomical standards.
The alien world could yield clues to the formation of our Solar System, which has an unusual lay-out.
The astronomers also detected water on the planet.
These findings indicate that it might be similar to planets in our Solar System.