In theory, could you possibly use Gravitational Waves as a way to detect and observe subatomic particles without disrupting them if the gravitational wave was small enough? And then translate that information to something we could see? My thinking is that the main way we have of observing things without touching them is by interpreting waves bouncing off of things. Sound waves are too big, and a lot of times light is even too big or at least, the light changes something about the particle you’re trying to look at, the only wave that could even exist on a smaller scale would have to be gravitational waves, right? Because they propagate through spacetime itself. Now, I don’t know a lot about gravitational waves themselves specifically, but I know they’re difficult to detect. Could being outside a major gravitational influence help in the detection of them?


1 Answer 1


Somewhat YES.

Yes in the sense, that theoretically gravitational waves have no upper limit of frequency, given that you can find gravitational source strong enough, you could get these waves scattered and detected from subatomic particles.

Issues, (mostly, practical ones):

  1. It's very hard to find/generate very energetic gravitational waves. High-Frequency relic gravitational waves (HFGW) is estimated to have upper limit of frequency about $30~GHz$, which is relic from the universe right after the Big Bang event. These gravitational waves will have energy-mass $\approx 10^{-4} eV$. On the other hand, neutrino mass-energy bound is set to be about $1~eV$. Neutrino are known to be very weakly interacting particles, so that neutrino detectors must be huge and put deeply under-ground to isolate all possible detector event causes and still they get rare neutrino evens. For comparison, rate is like about 1 event per 2 days from the early Sun neutrino experiment. So, HFGW detectors which could detect gravitational waves scattering from particles must be at least $10~000\times$ more sensitive than neutrino detectors to be useful (and this is only in optimistic scenario.)

  2. without disrupting them

    This is what really is impossible. In a quantum world any observation of particles, disrupts them, because for that test field must interact with particles. And interaction without affecting particle energy/position and other parameters is impossible at all. Either observation or "non-disrupted life" of particle, but not both. So gravitational waves is also not an exception here. If it scatters from particles or interacts otherwise - it disrupts it. Less disruption,- less info you get from such observation. It is as it is.


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