Aliens Watching Us

Rather than detecting our radio waves first wouldn't an alien civilization, if at all curious about the possibility of life elsewhere, detect our planet first? Think about it. Unless we run into some unexpected problem we are likely to have built instruments capable of directly imaging planets nearby to our own before the end of the 21st century. Perhaps even before 2040.

So as I see it there are four possibilities.

One, there is a civilization of technologically advanced aliens that has been observing us using very powerful telescopes. If within 100 or 200 light years of earth they probably suspect the fact that we have a technological civilization based upon measuring the changes in our atmosphere brought on by industrialization. They might be deciding or have already sent a message on this basis and SETI could detect it at any time.

Two, there is a species of intelligent aliens within 100 light years of us, but they have yet to advance to technological civilization. We will detect their planet using our telescopes sometime in the next century and then keep the planet under observation. If they advance to technological civilization anytime after this and we're still watching we'll detect it, suspect what is going on, and then send a message of our own hoping they'll detect it.

Three, there are intelligent aliens, but they aren't interested in discovering life elsewhere. They've either turned inward after achieving technological civilization, or are not that interested or capable of technology. We'll discover their planet if close to ours in the next century, but we won't be able to guess they are there or even if we do we won't be able to contact them.

Four, the most likely possibility, is that there are no intelligent aliens anywhere close enough to earth to ever be detected.