Deep Space Radar?

An old Internet story is making the rounds again, that the Aricebo antenna picked up 47 year old TV broadcasts bouncing back from some mystery object “or more likely, field of objects” some 25 light years away.


Some versions of the story are well written, others make absurd claims such as that the BBC has recovered lost Dr. Who episodes (not a chance in hell, for a number of reasons).

But the idea is intriguing. Could we not, in fact, create a deep space radar system to map the Oort cloud and once and for all detect every object within the solar system that might one day come to call?

Now this would be a very odd radar. It might, for example, be fixed to point always out away from the sun (or at least rotate very, very slowly), because it is looking for objects hundreds and thousands of light minutes away.

Further, might there be some value in some sort of deep space radar as an exploration tool? Well, it would require patience on a scale of which, frankly, I lack the patience to contemplate. And it might require an inconveniently star-sized power plant to power the thing. So maybe not. But then. . .