Are Earth's Search Technologies Too Primitive to Detect Advanced ET Life?

Are Earth's Search Technologies Too Primitive to Detect Advanced ET Life?: "Some of the world's leading astronomers -including Great Britain's astronomer royal, Sir Martin Rees- believe aliens, rather than using different radio waves or visible light to signal, may be using an entirely different communication medium such as ghostly neutrinos or with gravitational waves (ripples in the fabric of space-time) or using communication mechanisms we cannot begin to fathom."