The longest wavelength that we can measure using our current technology is in the microwave range, specifically around 1 millimeter (mm) to 1 meter (m) in wavelength. This range is commonly referred to as radio waves. Radio telescopes are capable of detecting and measuring these wavelengths, allowing us to observe and study celestial objects and phenomena.
While our technology has advanced significantly, there are practical limitations to measuring longer wavelengths. One key factor is the size of the detectors and antennas required to capture and analyze these waves. Building larger instruments becomes increasingly challenging as we move towards longer wavelengths. Additionally, the Earth's atmosphere can also introduce absorption and interference, which further limits our ability to detect extremely long-wavelength signals.
Regarding time dilation, it is important to note that time dilation does not directly affect our ability to measure longer wavelengths. Time dilation refers to the phenomenon where time runs slower for an object in motion relative to a stationary observer. However, it does not have a direct impact on the measurement of wavelengths themselves.
In summary, the current technological limitations and practical constraints restrict our ability to measure wavelengths beyond the radio wave range, which extends up to around 1 millimeter to 1 meter in length.