You're right to be skeptical, but this isn't a religious claim. It's the best prediction these scientists came up with based on current theories of relativity/cosmology and measurements from Hubble.
This is the best science can do when experimentation is impossible: apply theories to measurements.
The hypothesis is no more verifiable than a claim that our actions in this life determine our circumstances in the next one. Indeed, I have better evidence for an hypothesis regarding karma right here on HN.
This is the best science can do when experimentation is impossible: apply theories to measurements.