black of pores may explain a mysterious form of energy that makes up most of the universe, according to astronomers. existence of “dark energy” It has been inferred from observations of stars and galaxies, but no one has been able to explain what it is, or where it comes from.
The stuff, or matter, that makes up the familiar world around us is just 5% of everything in the universe. another 27% have dark matter, a shadowy model of ordinary matter that does not emit, reflect, or absorb light. However, most of the universe – about 68% – is dark energy.
New evidence that black holes may be the source of dark energy is described in a scientific paper Published in The Astrophysical Journal Letters. The study is the work of 17 astronomers in nine countries and was led by the University of Hawaii. The collaboration involved researchers in the UK based at STFC RAL Space, The Open University and Imperial College London.
Searching through data from nine billion years of cosmic history, astronomers have uncovered the first evidence of “cosmic coupling”Which would mean that the growth of black holes over time is linked to the expansion of the universe itself.
The idea that something can happen in a black hole is called vacuum energy (a manifestation of dark energy) is not particularly new and was actually discussed theoretically as far back as the 1960s. But this latest work assumes this energy (and hence the mass of the black hole) will increase over time as the universe expands as a result of cosmological coupling.
The team calculated how much dark energy in the universe could be responsible for this process. They found that black holes could potentially explain the total amount of dark energy measured in the universe today. The result may solve one of the most fundamental problems in modern cosmology.
rapid expansion
our universe began in the big bang About 13.7 billion years ago. The energy of this explosion of space and time caused the universe to expand rapidly, causing all the galaxies to fly away from each other. However, we expect this expansion to slow down gradually due to the effect of gravity on everything in the universe.
This is the version of the universe we thought we lived in until the late 1990s, when the Hubble Space Telescope discovered something strange. Observations of distant exploding stars have shown that, in the past, the universe was actually expanding more slowly than today,
So the expansion of the universe is not slowing due to gravity, as everyone had thought, but is speeding up. It was highly unexpected and astronomers have been struggling to explain it.
With this in mind, it was proposed that a “dark energy” was responsible for pushing things apart, compared to gravity pulling things together. The concept of dark energy was similar to a mathematical construct that was proposed by Einstein but later rejected – a “cosmic constant” Who resisted gravity and saved the universe from collapsing.
stellar explosion
But what is dark energy? The solution, it seems, may lie with another cosmic mystery: black holes. When are black holes usually born? Massive stars explode and die at the end of their lives, In these violent explosions, gravity and pressure compress large amounts of material into a small space. For example, a star with a mass similar to our Sun would be scattered over a space of a few tens of kilometers.
A black hole’s gravitational pull is so strong that not even light can escape it – everything is pulled in. There is a space in the center of a black hole called a. Persona, where matter is crushed into a point of infinite density. The problem is that the singularity is a mathematical construct that shouldn’t exist.
Black holes at the centers of galaxies are much more massive than those formed when stars die violently. These galactic “supermassive” black holes can weigh millions to billions of times the mass of our Sun.
All black holes grow in size by accreting matter, swallowing stars that come too close, or merging with other black holes. So we expect them to get bigger as the universe gets older.
In the latest paper, the team looked at supermassive black holes at the centers of galaxies and found that these black holes gain mass over billions of years.
radical rethink
The team compared the observations elliptical galaxies, which lacks star formation in the past and present. These dead galaxies have used up all their fuel, so any increase in their black hole mass during this time cannot be attributed to the normal processes by which black holes grow by accreting matter.
Instead, the team proposed that these black holes actually contain vacuum energy and are “coupled” to the expansion of the universe, so that they increase in mass as the universe expands.
This model neatly provides a possible origin of the dark energy in the universe. It also sidesteps the mathematical problems plaguing some studies of black holes, as it avoids the need for a singularity at the center.
The team also calculated how much dark energy in the universe can be attributed to this process of coupling. They concluded that it would be possible for black holes to provide the necessary amount of vacuum energy to account for all the dark energy measured in the universe today.
This would not only explain the origin of dark energy in the universe but also force us to fundamentally rethink our understanding of black holes and their role in the universe.
Much work needs to be done to test and confirm this idea, both from observations of the sky and from theory. But we may finally be in sight of a new way to solve the dark energy problem.
Astronomy Group Lead, Space Operations Division at RAL Space, and Visiting Fellow, The Open University
Reader in Astrophysics, Imperial College London
this article was originally published In Conversation.