Yea, but they would have to blink a significant portion of their galaxy for us to notice.
The top of our capabilities is indirect planet discovery. So alien civilization would need to affect ceartain stars on a scale that a planet does and make it look not natural, like prime number periods or something.
The top of our capabilities is indirect planet discovery. So alien civilization would need to affect ceartain stars on a scale that a planet does and make it look not natural, like prime number periods or something.