The universe is 13.8 billion years old, nothing travels faster than light, and yet the observable universe has a radius of 46.5 billion light years and a diameter of roughly 93 billion. This deep dive, built on Planck Space Observatory data, resolves that apparent contradiction by separating the movement of objects through space from the expansion of space itself, using the FLRW metric, the cosmic microwave background, and the concept of comoving distance.

From there the conversation maps what fills our cosmic bubble: roughly 10 to the 24 stars, hundreds of billions to two trillion galaxies, about 10 to the 80 atoms, and yet only 4.9 percent of the total energy density, with dark matter at 26.8 percent and dark energy at 68.3 percent. The hosts explain the End of Greatness, where large-scale structure gives way to uniformity beyond about 20 ...