Interesting article in the Guardian about the difficulties astronomy has in pinning-down the Hubble Constant.
Astronomers have reached a fundamental impasse in their understanding of the universe: they cannot agree how fast it is flying apart. And unless a reasonable explanation can be found for their differing estimates, they may be forced to completely rethink their ideas about time and space. Only new physics can now account for the cosmic conundrum they have uncovered, many believe.
"We were getting better and better at understanding the universe and yet the closer we have been looking, the more we have found there are all these mysterious components.”
Over the decades, these surprises have included the discovery of dark matter – believed to be made up of as yet undetected particles – whose extra gravitational pull explains why galaxies do not fly apart. In addition, astronomers have also discovered the existence of dark energy, which is accelerating the rate at which the cosmos is expanding.
“Those two discoveries were remarkable enough, but now we are facing the fact there may be a third phenomenon that we had overlooked – though we haven’t really got a clue yet what it might be.”
www.theguardian.com
Astronomers have reached a fundamental impasse in their understanding of the universe: they cannot agree how fast it is flying apart. And unless a reasonable explanation can be found for their differing estimates, they may be forced to completely rethink their ideas about time and space. Only new physics can now account for the cosmic conundrum they have uncovered, many believe.
"We were getting better and better at understanding the universe and yet the closer we have been looking, the more we have found there are all these mysterious components.”
Over the decades, these surprises have included the discovery of dark matter – believed to be made up of as yet undetected particles – whose extra gravitational pull explains why galaxies do not fly apart. In addition, astronomers have also discovered the existence of dark energy, which is accelerating the rate at which the cosmos is expanding.
“Those two discoveries were remarkable enough, but now we are facing the fact there may be a third phenomenon that we had overlooked – though we haven’t really got a clue yet what it might be.”

The Hubble constant: a mystery that keeps getting bigger
Scientists have found a discrepancy in estimates for the rate of expansion of the universe. Why is this and what does it mean?