For the first time, astronomers used supermassive black holes immediately after the Big Bang to measure the universe's rate of expansion. We now have a greater mystery in our hands than the answer this effort has given.
It turns out that the universe is growing faster than expected. This could mean that the dark energy driving the acceleration of this expansion, sometimes interpreted as the cosmological constant described by Albert Einstein, is not so cosmologically constant.
Instead, it could become stronger.
The rate of expansion of the universe is called the Hubble constant, and it was incredibly difficult to determine. Every test seems to have a different result. Recently, due to data from the Planck satellite, the cosmic microwave background was set at 67.4 kilometers per second per megaparse with less than 1
Other methods commonly use "standard candles" or objects of known luminosity, such as Cepheid variables or Type Ia supernovae, from which the distance can be calculated based on their absolute size.
Last year, a Cepheid variable star calculation of the Hubble constant yielded a result of 73.5 kilometers (45.6 miles) per second per megaparsec. So you can see why astronomers repeatedly come across this weird cosmic bear.
However, a few years ago, astronomers realized that the distance to another object can also be accurately calculated. Enter the quasars with their black holes.
Quasars are among the brightest objects in the universe. Each is a galaxy orbiting a supermassive black hole that actively feeds material. Its light and radio emissions are caused by material around the black hole, called the accretion disk, which generates intense light and heat through friction that swirls like water around a drain.
They also emit X-ray and ultraviolet light; As discovered by astronomers Guido Risaliti of the Università di Firenze, Italy, and Elisabeta Lusso of Durham University, UK, the ratio of these two wavelengths produced by a quasar varies with ultraviolet luminosity.
Once this luminosity is known, as calculated from this ratio, the Quasar can be used like any other standard candle.
This means that we can continue to measure into the history of the universe.
"The use of quasars as standard candles has great potential as we can observe them at much greater distances than we of type Ia supernovae, and use them to study earlier epochs in the history of the cosmos", said Lusso.
The researchers collected UV data on 1 598 quasars of just 1.1 billion euros 2.3 billion years after the Big Bang and used these distances to calculate the rate of expansion of the early universe.
They also compared their results to the type Ia supernova results of the past 9 billion years and found similar results for overlaps. But in the early universe, where only quasars provide measurements, there was a discrepancy between what they observed and what was predicted based on the standard cosmological model.
"We watched quasars only a billion years after the Big Bang and found that the rate of expansion of the universe has been faster than we expected," said Risaliti.
"This could mean that the dark energy grows stronger the older the cosmos gets."
We do not really know what dark energy is – we can not see or recognize it. It's just the name we give to the unknown repulsive force that seems to accelerate the expansion of the universe over time.
(Based on this expansion rate, astrophysicists have calculated that the dark energy accounts for about 70 percent of the universe – that is, more accurately.) The rate of expansion will also allow us to more accurately calculate the volume of dark energy.)
dark energy increases over time, the scientists believe that this would not mean Einstein's cosmological constant. But it would explain the odd numbers – and maybe even the discrepancy between the results of the previous Hubble constant.
So far, much work needs to be done to test this result and see if it is certain.
"This model It's very interesting because it might solve two puzzles at once, but the jury is definitely not eliminated yet, and we need to look at many more models before we can solve this cosmic puzzle." said Risaliti.
. Some scientists suggested that new physics may be needed to explain this discrepancy, including the possibility that dark energy may gain strength. Our new results are in line with this proposal.
The researches of the team were published in the journal Nature Astronomy and can be read in full on the preprinted resource arXiv.