8. MR diagram Again
Putting it all together: plot objects in the universe on a graph of mass versus radius
The edge of the universe
The event horizon of black holes
Compton wavelength
Quantum black holes and the planck length
The planck time
Is the universe a black hole?
8. MR diagram:
Putting it all together: plot objects in the universe on a graph of mass versus radius
This time we will examine the boundaries.
The edge of the universe in space and time. Why we cannot yet see beyond the edge of the universe. How spacetime shows that the edge of the universe is actually a point from which the universe originated. Yet this boundary is moving outward at the speed of light.
The event horizon of black holes. Information cannot cross the event horizon of a black hole from inside to outside. So we cannot get answers to experiments conducted inside a black hole, thus the event horizon is a boundary to scientific understanding.
The Compton wavelength is the shortest wavelength associated with a mass. We cannot ask detailed questions of an object with lengths shorter that its Compton wavelength, thus it is a boundary to science.
The history of science has been the pushing back of these boundaries.
Interesting features occur where the lines on the MR diagram intersect.
Where the black hole event horizon intersects with the Compton wavelength we get a quantum black hole. The length scale at which this happens is the planck length. This is the size of a string in string theory and is 15 orders of magnitude smaller than we can currently “see” with our biggest particle accelerators.
The planck time is the time it takes light to cross the planck length.
Where the Black Hole line hits the edge of the universe we see that the visible universe as we understand it is not a black hole.
Where the Compton wavelength meets the radius of the universe we find the smallest mass particle that can hve one wavelength fit inside the universe.
Scientific Explorations with Paul Doherty 

18 October 2011 