Does anyone really understand general relativity well enough to have an intuitive grasp of the universe?

It is all a matter of perspective.

Physicists and astronomers who spend all of their professional lives studying gravity and distant astronomical phenomena, amass an enormous amount of intuition about the mathematics of relativity. Through constant contact with the technical details they develop the best intuition that is humanly possible.

Those who see relativity and cosmology as a recreation, and who never grapple with any of the mathematical details or experimental investigations, probably never achieve an intuitive grasp of relativity.

Like learning an instrument, there is a wide gulf between the kind of experiences many of us have had in grade school just learning how to sound the notes, and the kind of proficiency enjoyed by professional musicians who practice 4 to 8 hours EVERY DAY.

To the extent that general relativity is showing us the right way to think about the physical universe, yes, there are in fact many people who have an intuitive grasp of what the universe looks like. How they choose to 'visualize' this world-view may differ from individual to individual, but they all agree about the underlying mathematics.

Return to Dr. Odenwald's Gravity page at the Astronomy Cafe Blog.