And cosmologists race to win a “great cosmic bake-off” to produce a new one, says astrophysicist:
Just as cosmological measurements have became so precise that the value of the Hubble constant was expected to be known once and for all, it has been found instead that things don’t make sense. Instead of one we now have two showstopping results.
On the one side we have the new very precise measurements of the Cosmic Microwave Background – the afterglow of the Big Bang – from the Planck mission, that has measured the Hubble Constant to be about 46,200 miles per hour per million light years (or using cosmologists’ units 67.4 km/s/Mpc).
On the other side we have new measurements of pulsating stars in local galaxies, also extremely precise, that has measured the Hubble Constant to be 50,400 miles per hour per million light years (or using cosmologists units 73.4 km/s/Mpc). These are closer to us in time.
Both these measurements claim their result is correct and very precise. The measurements’ uncertainties are only about 300 miles per hour per million light years, so it really seems like there is a significant difference in movement. Cosmologists refer to this disagreement as “tension” between the two measurements – they are both statistically pulling results in different directions, and something has to snap.
So what’s going to snap? At the moment the jury is out. It could be that our cosmological model is wrong.Thomas Kitching, ““The universe’s rate of expansion is in dispute – and we may need new physics to solve it”” at The Conversation
We’re going to ask our physics color commentator Rob Sheldon, and then we will get back to you. Meanwhile…
See also: Do we even need dark energy to explain cosmic expansion?
Supernova analysis questions dark energy cosmic acceleration
Take back Nobel prizes for accelerating expansion of universe? Dark energy might be an illusion say some researchers. But we thought only a denialist was allowed to doubt the accelerating expansion of the universe. Rules change?
Expanding space bubbles could doom dark energy? Is it possible that the sheer ability to make up theories without consequence is adding to the confusion?
Dark energy made by black holes? But do we know that dark energy actually exists? Finding some would help us decide whether to cheer on or deprecate the revolution.
String theorists losing bets? Resorting to “denialism”?
and
Cosmic inflation theory loses hangups about the scientific method