Illustration illustrating communication between planets outside the solar system from Earth's perspective. New research done using the Allen Telescope Array has looked for this kind of communication in the TRAPPIST-1 star system, similar to the communication between Earth and our rovers on Mars. Credit: Zaina Sheikh.

Illustration illustrating communication between planets outside the solar system from Earth's perspective. New research done using the Allen Telescope Array has looked for this kind of communication in the TRAPPIST-1 star system, similar to the communication between Earth and our rovers on Mars. Credit: Zaina Sheikh.