Title: The Planck scale: relativity meets quantum mechanics meets gravity. (from Einstein Light)
Headings: The Planck scale: relativity meets quantum mechanics meets gravity.
The Planck scale: relativity meets quantum mechanics meets gravity.
Defining the Planck scale
Combining quantum mechanics, gravity and relativity
What do space and time mean at the Planck scale?

Content: Does Planck-scale physics challenge relativity? According to Special Relativity 's time dilation and length contraction, two observers with relative motion are condemned to eternal disagreement about times and lengths. Or are they? They will disagree over the arbitrary times measured in seconds and lengths measured in metres or whatever units. They would also disagree over clock ticks, atomic vibrations and light wavelengths. But what if there were some absolute time and length, determined by the very nature of the universe? And what if these quantities could be measured in different frames of reference? Wouldn't the observers have to agree on those having the same value, if they agree on the same laws of physics? Well, there is an abolute length and an absolute time. It's possible that we'll never be able to measure them, so any threat posed to relativity is distant and perhaps even hypothetical.