A few workweek ago , a team of astronomers ball over the world when they annunciate that they had detectedevidence of cosmic inflation — an event that come 10 - 34seconds after the Big Bang . But what has the Universe been up to since then ? Observations and measuring tell us that it is expanding , but at what rate ? How has that rate changed over prison term ? The research worker operate the Sloan Digital Sky Survey ( SDSS ) announced yesterday at a conference of theAmerican Physical Societythat they have made the best measurement yet of the expansion of the Universe .
The team investigated the cosmos as it was 10.8 billion year ago , at about 25 % of its current age . They found that the Universe was expatiate at a rate of one percent every 44 million years .
This conclusion was made by studying atomic number 1 gas clouds and 140,000 quasars . quasi-stellar radio source are form when high - fastness accelerator sire too close to a black hole and is then bounced off due to electromagnetic forces . The rubbing heat up the petrol which have it to glow in beautiful color , revealing the quasi-stellar radio source as a massive jet of brilliant light . By value how much Inner Light from the quasi-stellar radio source is obstruct by cloud of intergalactic H gasolene over clip , the squad was able to determine the pace at which the Universe was expand .
This technique expand upon prior enquiry the team completed just over a year ago . “ A little over a year ago we try this for the first time and demonstrated that it really act upon ” , Dr Matthew Pieri , from the University of Portsmouth say in apress release . “ Now we ’re back with doubly as much data and with remarkable precision of 2 per cent . We are measuring the expansion of the universe with keen point . Like the rings of a tree trunk that tell is its eld , each quasar spectrum becomes an archive of the world ’s chronicle . ”
About 6 billion years ago , dark energy start to dominate the Universe . Dark energy , which now comprises an count on 70 % of the Universe , is believe to be the perpetrator behind the speedup . There is still much we do n’t sleep with about sinister energy , but scientists believe that the density of saturnine vim remains unvarying , even in the face of an expound Universe . It does n’t “ dilute ” the way a salty solution would if you kept increase the volume of urine . This tenaciousness of concentration likely playact a persona in the acceleration of enlargement . How or why does dark energy do this ? That remains to be find .
Pieri enigmatically states that there is a bit of tension between the late resolution and what was expected based on Cosmic Microwave Background . “ It ’s remaining , ” he notes , “ but nothing you want to hang your hat on just yet — it ’s run to be fun finding out where the trueness lies " .
