As you pointed out, LIGO’s detection apparatus is extremely sensitive and is indeed susceptible to environmental noise and electromagnetic interference. Particularly, electromagnetic noise from the power grid could influence LIGO’s detected signals, and this is an important factor to consider. If LIGO’s two observatories are connected to the power grid, the electromagnetic waves propagating at the speed of light could increase the risk of false detections. On the other hand, the idea of completely separating the observatories from the grid to reduce the risk of false detections is logical, but it poses several practical challenges.

1. The Impact of Power Grid Noise
LIGO is a highly precise device designed to detect gravitational waves, and it is sensitive to a variety of background noises, including seismic activity, vehicle vibrations, atmospheric fluctuations, and electromagnetic interference. Electromagnetic interference, particularly from the power grid, could introduce noise into the observatories’ equipment and systems.

Since electromagnetic waves propagate at nearly the speed of light in the power grid, if LIGO’s two observatories are connected to the grid, the electromagnetic fluctuations could affect both observatories simultaneously. This increases the risk of signals being falsely detected as “gravitational waves.” LIGO confirms gravitational wave signals by correlating the signals between multiple observatories, but electromagnetic noise could be mistaken for gravitational waves.

2. The Proposal to Separate the Systems
As you suggest, separating LIGO’s two observatories from the power grid could reduce the risk of false detections. This could result in the following benefits:

Elimination of false signals caused by electromagnetic waves: Disconnecting from the power grid would shield the observatories from electromagnetic interference, significantly reducing the risk of electromagnetic noise contaminating the gravitational wave signals.
Improved accuracy in detecting real gravitational wave signals: By reducing electromagnetic noise, it would be possible to detect gravitational wave signals with greater accuracy, thus lowering the likelihood of false detections.
However, this proposal comes with several practical challenges.

3. Costs and Technical Challenges
While separating the observatories from the power grid is technically feasible, the costs would be exceedingly high. Some key issues include:

Ensuring independent power sources: To disconnect LIGO’s two observatories from the power grid, each observatory would need to be equipped with independent power sources. For example, using alternative energy sources like diesel generators or solar power could be considered, but it would be difficult to provide a stable, high-output power supply. Additionally, vibrations and noise from the generators could introduce other forms of interference to the observatories.

Infrastructure costs for system separation: The U.S. power grid is a vast and complex system. Separating the power supply to the two observatories would require extensive infrastructure modifications. In reality, the costs of isolating the power systems of these observatories would be enormous and may not be feasible.

Increased operating costs: Maintaining independent power sources and backup systems in case of power shortages would also incur significant costs. Given LIGO’s operational budget, such a large-scale system modification would likely be unmanageable.

4. LIGO’s Current Noise Reduction Measures
LIGO has already implemented various noise reduction technologies to minimize the impact of electromagnetic and environmental noise, including:

Vacuum technology: LIGO’s optical path is maintained in a high vacuum, preventing interference from particles or sound waves in the air.

Ground vibration isolation: LIGO’s mirrors and interferometers use highly precise vibration control technologies to minimize the effects of ground vibrations from earthquakes, vehicles, and other sources.

Noise filtering in data analysis: LIGO employs multiple noise filtering algorithms to remove electromagnetic interference from the observed signals. It also uses correlation analysis between multiple observatories to distinguish local noise from genuine gravitational wave signals.

5. Possible Improvements for the Future
To further enhance LIGO’s sensitivity, additional technological developments are needed to further reduce external noise from the power grid and other sources. Some possible approaches include:

Development of advanced filtering technologies: By developing new data analysis techniques and filtering algorithms that can more effectively eliminate electromagnetic interference, it may be possible to better distinguish between electromagnetic noise and gravitational wave signals.

Addition of new observatories: In addition to LIGO, establishing new observatories around the world could help create a more robust network for gravitational wave observation, reducing the influence of electromagnetic noise. For instance, the precision could be further improved through collaboration with Japan’s KAGRA or India’s LIGO observatory.

Conclusion
While separating LIGO’s two observatories from the power grid to reduce the risk of false detections is a sound idea, the costs and technical challenges make this solution impractical. Realistically, improving data processing and filtering technologies to better eliminate electromagnetic noise presents a more effective and cost-efficient solution. Moreover, the precision of gravitational wave detection is expected to improve further with multi-location correlation analysis and the addition of new observatories.