How can we know that nothing travels faster than the speed of light (3 x 10^8 m/s)? If there were certain physical phenomena that could travel faster than light, we wouldn't be able to perceive it, since light has a limited fixed velocity. So, what if dark matter and dark energy are just phenomena that actually travel faster than light and we can't detect them through light wavelengths. We can measure its gravitational effects, but not its emission spectra.