Since it appeared, the Universe has expanded at a rate described by the hubble constant. However, the value has been subject to different estimates and controversies. Moreover, although in the original formulation, this parameter appeared as a fixed value number, the relativistic cosmological models on which the Big Bang is based suggested that the Hubble parameter was not really a constant but a parameter that varied slowly with the time, so modernly many authors refer to the "Hubble constant" more properly as the Hubble parameter.
In fact, researchers from the University of Queensland Tamara Davis, in a recent study published in Science, provide new evidence that the universe would expand at a rate so different from what we thought the universe would be about 2 billion years younger than sustained.
According to Hubble's law, a measure of the inertia of the expansion of the universe is given by the Hubble constant. From this observational relationship it can be inferred that galaxies move away from each other at a speed proportional to their distance.
The most recent calculations of the constant, using the data from the WMAP satellite, began in 2003, allowed to give the value of 71 ± 4 (km / s) / Mpc for this constant, which means that the universe is 13,781 years old, 306 million years. In 2006 the new data provided by this satellite gave the value of 70 (km / s) / Mpc, + 2.4 / -3.2, so the universe would be 13.978.182 million years old.Scheme of light paths in a gravitational lens. The images of distant objects take the form of arcs surrounding the intermediate mass object.
But, after careful analysis using gravitational lenses (They are formed when light from distant and bright objects such as quasars curves around a massive object (such as a galaxy) located between the emitting and the receiving object), in which researchers from the United States, Germany, Countries have been involved Low, Taiwan and Japan, the age of the Universe would be lowered about 2 billion years over 13.7 billion years of the consensus value.
The researchers applied this technique to measure the angular diameter distance to two gravitational lens systems and used them as reference points to recalibrate an existing measurement of H0, which they report as 82 +/- 8 km / s / Mpc.