We learned   that the universe is expanding less than 100 days ago and that the elaboration is accelerated less than 20 geezerhood ago . It   seemed we were really starting to get   the knack of it and then science make a curve ball ball .

We have two methods to estimate the current rate of enlargement of the macrocosm , which is known as the Hubble Constant . Both methods have improved staggeringly in the last decade , and while they were once in agreement , they now take issue by   about8 percent .

One method use wiz and stellar blowup to measure the aloofness of coltsfoot , which is then used to estimate the Hubble Constant . The other method acting utilize the cosmic microwave backdrop , the light from the Big Bang itself . The methods   are solely independent of each other and the fact that they do n’t agree bring up a fortune of interrogative sentence .

In a commentary forNature Astronomy , Professor Wendy Freedman talk over what the current state of the field is and what we might learn in the hereafter to puzzle out this proceeds . The two measurements have some doubtfulness consort with them , but even take that into account , the two appraisal still do n’t overlap .

“ Is the discrepancy material or is this a ‘ tautness in a teapot ? ’ "   Professor Freedman state in thepaper . " The obvious possibility is that one or both of the methods may stick out from unknown taxonomical fault . "

What she talk about is that there are several possibilities . If only one of them is correct , then we are either missing something about the nature of stars or about the nature of the early world . If both of them are right , then we might have begin ensure the effects of a new strong-arm phenomenon . instead , the measurements might be due to “ as - yet unrecognized uncertainties , ” just to stay on the sceptical side .

Both methods appear to be well think out and tested , and they are supported by abundant experimental evidence , but clearly something is going on , otherwise we would n’t have a public debate on the value of the Hubble Constant .

Physical mechanisms   have been proposed to increase the economic value we get from the cosmic microwave background knowledge ( CMB ) , such as unexpected effects of sorry matter and obscure vim or maybe physics beyond the standard fashion model . This is exciting on paper , but other mensuration of the CMB show that it behaves as predicted , so maybe there ’s no physics hide there .

“ The history of cosmogeny has abundant examples both of discrepancies that ushered in raw discoveries , and others that turn out to be unknown systematic error , " compose Freedman . " base on the current data , I believe that the jury is still out . ”

What we need is more data point . The first method acting uses the light of stars and supernova that have a specific brightness . This property allows us to use them as standard wax light , like remote sign posts placed across the cosmos . TheGaia missionand the James Webb Space Telescope will see these objective further than ever before , and they should refine the value of the Hubble Constant we get from galaxies . To improve on the other time value , we will have to wait for next CMB experiments , like the South Pole Telescope and the Atacama Cosmology Telescope , to come online .

Hopefully , that will provide some limpidity to   this fascinating argument .