The critical geometry of a thermal big bang Niayesh Afshordi, Joao Magueijo (Submitted on 9 Mar 2016 (v1), last revised 8 Nov 2016 (this version, v2)) We explore the space of scalar-tensor theories containing two non-conformalmetrics, and find a discontinuity pointing to a "critical" cosmological solution. Due to the different maximal speeds of propagation for matter and gravity,the cosmological fluctuations start off inside the horizon even without inflation, and will more naturally have a thermal origin (since there is never vacuum domination). The critical model makes an unambiguous, non-tuned prediction for the spectral index of the scalar fluctuations: nS=0.96478(64). Considering also that no gravitational waves are produced, we have unveiled the most predictive model on offer. The model has a simple geometrical interpretation as a probe 3-brane embedded in an EAdS2×E3 geometry. Subjects: General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th) Journal reference: Phys. Rev. D 94, 101301 (2016) DOI: 10.1103/PhysRevD.94.101301 Cite as: arXiv:1603.03312 [gr-qc] proposes that light can travel faster than c can be tested via cosmic microwave background spectral index value of 0.96478. so instead of inflation, light can exceed c in the earliest moments of the big bang credibility of this theory and how would it affect the rest of fundamental physics if this theory is verified? i.e instead of inflation, light was faster than c. so no need for an inflaton. how does it effect the structure of QFT and SM if light can exceed c during big bang, and this and not inflation explains universe? ramifications for BSM including string/lqg?