The KBC Void (or Local Hole) is an immense, comparatively empty region of space, named after astronomers Ryan Keenan, Amy Barger, and Lennox Cowie, who studied it in 2013.
As with other voids, it is not completely empty; it contains the Milky Way, the Local Group, and the larger part of the Laniakea Supercluster.
Some authors have proposed the structure as the cause of the discrepancy between measurements of the Hubble constant using galactic supernovae and Cepheid variables (72–75 km/s/Mpc) and from the cosmic microwave background and baryon acoustic oscillation data (67–68 km/s/Mpc).
[9] Important deficiencies were subsequently pointed out in this analysis, leaving open the possibility that the Hubble tension is indeed caused by outflow from the KBC void, albeit in the context of MOND gravity rather than general relativity.
[6] It was later discovered that this outflow model successfully predicted the bulk flow curve, an important measure of the velocity field in the local Universe.