For the first time in history, scientists measured the speed of the expansion of the universe using supermassive black holes formed shortly after the Great Bang. And their results have more questions than answers, writes Science Alert.
It turns out that the Universe is expanding faster than expected by the results of this measure. Scientists describe the expansion of the universe as a process determined by dark energy. And the latter is often defined by a cosmological constant, described for the first time by Albert Einstein. Now, the result of the new study shows that the cosmological constant may not be as constant as that.
It may be increasing.
The speed of the expansion of the universe is called the Hubble constant. Determining its exact size is very difficult. Nearly all research results in different results. Recently, according to the Planck satellite data that performs space microwave monitoring, this constant is 67.4 kilometers per second megaparsec, with a maximum error of 1 percent.
Other methods of measurement are often based on "standard candles" or known brightness objects (stars with cefeides or supernova type Ia), the distance that can be determined by absolute light.
Last year's estimate based on cefeides provided a result of 73.5 (km / s) / mpc. Thus, after evaluating a large difference in results, we can understand why astronomers are concerned and measure after measurement.
However, a few years ago, astronomers realized that it was possible to determine the distance and other types of objects: quasars and black holes.
The quasars are one of the most prominent objects in the universe. These are the active nuclei of the galaxies: they shine because the supermassive central galaxy hole actively nourishes the surrounding material. The visual and radio spectrum emissions are caused by the rotation material of the performance disk: this material, as if the water flows into the drain hole, rotates to form a tremendous friction and heat,
The Quasars also emit X-rays and ultraviolet rays. Guido Risaliti, a scientist at the University of Florence (Italy) and Elisabeta Lusso, a scientist at the University of Darhem (United Kingdom), found that the proportion between these two wavelengths varies according to absolute ultraviolet light.
When this light is known (it can be counted in proportion), the quasar can be used like any other "standard candle".
This means that measurements can be made for the future of the Universe.
"The use of quasars like standard candles has great potential because we can see them far beyond the supernova type Ia, so we can see a much older era in the history of space," Lucas said.
Scientists estimated 1,598 quasar, shining between 1,1 and 2,3 million. From the beginning of the universe, the UV light data and the distances to these celestial bodies calculated the speed of expansion of the early universe.
They also compared the results of the rate of expansion of the universe calculated based on type Ia supernovae, the last result in a period slightly more than about 9,000 million dollars. years after the beginning of the Universe, and the results are very similar. However, the speed of expansion of the primitive Universe does not correspond to the expected increasing speed of expansion of the universe of the standard cosmological model.
"We observed quasars just one billion years after the great explosion and found that the expansion velocity of the universe so far was greater than expected. This can mean that dark energy is getting stronger with the aging of the cosmos," said Risaliti .
In fact, we do not know what dark energy is that we can not see or measure. It is only the name that gave rise to an unknown push force that seems to increase the expansion of the universe over time.
According to the speed of the expansion of the universe, astrophysicists estimate that dark energy should be up to 70 percent. All universes, so adjusting the speed of expansion, will allow us to calculate more precisely the amount of dark energy.
If the density of dark energy increases over time, then, according to scientists, this should mean that the cosmological constant of Einstein is not constant. However, this would explain the strange number of measures and perhaps the differences between the Hubble constants previously measured.
But saying something with confidence requires an independent verification of these measurement results.
"This model is quite interesting because it can help you solve two tasks at the same time, but there is no definitive solution to the problem and, before declaring that this cosmic riddle is resolved, we will have to look much closer with many more models. scientists are considering that new physics may be necessary to explain these discrepancies, including the possibility of increasing dark energy. Our new results support these deliberations, "says Risaliti.
The results of the study were published by Nature Astronomy, and the article can be read entirely by ArXiv.