The sun, our star, emits something on the order of 400 terawatts (trillion, trillion watts; 15 zeros) of radiation. Per second. It is the biggest thing we have going for us. It lets us see, keeps us warm, powers our plant life.
In examining the question, “is earth alone?” we might turn to the sun. Launched in 2009, the Kepler space telescope has been finding remote planets. It has definitely found over one hundred such planets, and has thousands more unconfirmed. It does this work by focusing on the stars. It looks for telltale changes in what the star looks like over time, looks for a dimming that is caused by an orbiting planet moving between the star and the telescope.
The planets are too distant to be seen (yet?) by our instruments. But the stars, putting out terawatts of energy per second, we can see the stars.
And if we wish to signal to other intelligent life, or if it wishes to signal to us, the stars may be the most obvious and best bet. Because where else are we going to pick up a transmitter that can output terawatts?
But the trouble is how to wire this massive, powerful transmitter. As small as we are, with as limited resources as we have, it seems improbable we can make much of an impact on the solar output in any meaningful way. And even if we could, what way would that be, that would produce a detectable difference that would be definitive proof of life to aliens across the galaxy?
More importantly, what should we look for in the stars we can see?
The SETI Institute has been looking for intelligent life out there. But they tend to look for the alien equivalent of terrestrial signals: microwaves, radio waves, laser beacons. But, as far as I know, they do not look at the stars themselves, for anomalous readings that might indicate some subtle tampering by a local intelligence.
In a few hundred years, maybe, we will have advanced our space program and asteroid catalog far enough that we might endeavor to shift some asteroids about. We might do this with minimal effort, using a chain reaction in which we nudge one or a few asteroids ever so slightly. In this effort, we might produce a distinctive pattern for aliens who happen to glimpse our star. Maybe one that gives some sort of prime-number-based sequence to the next generation of alien Kepler-esque telescopes.
We might look for the same sorts of patterns in the stars we examine with our next generations of planet-finders.
Or maybe there is some other property of the stars we will learn to manipulate more easily? That we might find alien stars exhibiting the same changes?
What secrets do you see looking up at the stars? What secrets do you fail to see?