from Wiktionary, Creative Commons Attribution/Share-Alike License.
- adjective Insufficiently
from Wiktionary, Creative Commons Attribution/Share-Alike License
Thus the slightly larger expansion rate of the underdense regions makes the measured expansion rate appear to accelerate.
The idea here is that as structure forms, your overdense regions become smaller, while your underdense regions become larger.
With a cosmological constant, for instance, the potential becomes shallower as the light traverses it, so the blueshifting as it goes in outpaces the redshifting as it comes out, making for a small blueshifting of the light as it passes through overdense regions, and a small redshifting as it passes through underdense regions.