LE FIGARO. - How can we explain the tension between the two values found for the Hubble constant
?
YANN MAMBRINI. -
If we assume that Adam Riess's observations are correct, which is entirely plausible even if it still needs to be confirmed by independent techniques, then this means that the expansion of the Universe is a little larger today than what could be predicted by studying the cosmic microwave background
(or CMB
: these are the first photons which managed to "
escape
" 380,000
years after
the big bang
, when the Universe has become transparent, Editor's note)
. One way to reconcile the two approaches is to imagine that the value deduced from the CMB is slightly underestimated because it would miss a phenomenon. There are different theoretical avenues.
Which ones
?
The most attractive for me is that of “early dark energy”
(Early Dark Energy
; the Frenchman Vivian Poulin, from the University of Montpellier…