Recently, there has been a lot of talk of being able to detect gravity waves. The dreamer in me definitely loves that idea. An article on Gizmodo by Jennifer Ouellette discusses that they think they can detect waves made by very large objects.
Assuming that they have figured out how to measure gravity waves, how can we use it? I think we have discovered our first long range detection system for alien craft. Similar to Radio Direction Finding techniques, we will have Gravity Direction Finding systems.
These systems will “listen” for the waves, in all directions. It should be linked to provide a direction finding solution on where the object that caused the wave is located. The detection system will need to be able to determine which part of the sensor first registered the wave. That site will then send their direction solution to a central system. All sites in the cluster will report their solutions and the central system will calculate where the object is.
In time, we will be able to increase the sensitivity of the detection system. The more sensitive the system the better chance we can “listen” for transient gravity waves. Most objects in space are fairly stationary, in a relative sense, to us. We can soon identify all the larger waves that will come from one particular direction (like distant stars or black holes).
A space craft, asteroid or comet would be moving across the spectrum. Also this is probably more than a single wave, so successive waves will hit different parts of the sensor over time. Most stars would probably hit the same sensor. A comet or asteroid would, over time transit across the sensor giving a track to follow.
Assuming that space craft would need to be at higher speeds than a comet or asteroid, to make space travel feasible, they would quickly pass along the sensor head. While we could not really catch them in real time, we could tell of their passage.
This system probably could not detect craft too far away from our system, due to background noise. If a craft passed half way through the Oort Cloud, it would take almost 140 days for the gravity wave to get near earth. Our Oort Cloud goes out 1-2 light years which might or might not be a navigation hazard for interstellar travel.
The good news is that we probably can track an object coming into our solar system. With gravity waves traveling at light speed and assuming a craft would have to slow down their approach into the solar system, we should get a “hit” on our Gravity Direction Finding system before they show up.
I guess the worse thing would be to see a lot of UFOs come into the Kuiper Belt, stop for a short time, then move on. Boy that would be a massive hit on our self-confidence. Aliens find us boring.
So while we wait to see if E.T. has an interstellar highway near us, we can always use this to track asteroids and comets. A noble cause and something near and dear to most of us.