Dark energy is a mysterious phenomenon that works against gravity and is responsible for accelerating the expansion of the universe.
dark energy
Dark energy makes up up to three-quarters of the energy mass of the universe, but its fundamental nature has eluded physicists for decades. Dark energy has no real connections to dark matter, other than sharing the word dark, which just means that scientists don’t really know what this stuff is.
Interpretation of dark energy
But in 2023, scientists discovered evidence that dark energy can be explained by some kind of energy stored inside black holes. If this is true, the discovery means that our current models of the universe will not have new forces or fields beyond Einstein’s concept of gravity in order to explain dark energy. However, follow-up results may need to confirm the results before they can be widely accepted by physicists as an explanation for dark energy.
Discover dark energy
American astronomer Edwin Hubble noticed in 1929 that the farther a galaxy is from Earth, the faster it is moving away from us, according to the Hubble Space Telescope website. This does not mean that our planet is the center of the universe, but rather that everything in space is moving away from everything else at a constant rate.
Almost 60 years after the discovery of Hubble, scientists made another amazing discovery. Researchers have long tried to accurately measure cosmic distances by looking at the light of distant stars. In the late 1990s, after examining distant supernovae, two independent teams found that the light from stellar explosions was weaker than expected.
This indicates that the universe is not only expanding, but also accelerating.
This discovery has given physicists a reason to puzzle their heads ever since, and its discoverers also won the Nobel Prize in Physics in 2011.
What does dark energy do?
Researchers have used their knowledge of the phenomenon to build models of the universe that explain everything from the Big Bang to the large-scale structure of galaxies in modern times. Some of these models predict that dark energy will tear apart everything in existence billions of years from now.
The main explanations for dark energy are that it is a type of pent-up energy embedded in the fabric of space-time.
vacuum energy
Baojiu Lee, a mathematical physicist at Durham University in the United Kingdom, previously told Live Science: “This simple model works well in practice, and is a direct addition to the cosmological model without the need to modify the law of gravity.”
But the idea comes with one major problem: Physicists predict that the vacuum’s energy value should be 120 orders of magnitude higher than what cosmologists observe in measurements, Lee said.
The universe is expanding
Scientists have used measurements from ancient, dormant black holes to prove that these giant cosmic planets are growing faster than expected. The results indicate that black holes contain a kind of vacuum energy inherent in the fabric of space-time that could explain the expansion of the universe, all within the framework of Einstein’s theory of relativity. If the result holds, it means that no new physics will be needed to explain dark energy.
They published their findings in two papers in The Astrophysical Journal and The Astrophysical Journal Letters.
forces in the universe
An alternative idea posits that dark energy is an additional fundamental force, joining the four already known (gravity, electromagnetism, and the strong and weak nuclear forces). But this conjecture does not explain why humans do not notice this extra force in our daily lives. Therefore, theorists have also built creative models that suggest that this mysterious force is hidden in some way. The measured value of dark energy is currently the subject of intense debate among competing factions in physics. Some researchers measured the strength of dark energy using the cosmic microwave background, a faint echo of the Big Bang, and produced one estimate.
Dark energy force
But other astronomers who measure the strength of dark energy using the light of distant cosmic objects have produced a different value, and no one has yet been able to explain the discrepancy. Some experts have suggested that the strength of dark energy varies over time, although proponents of this idea have yet to convince most of their peers of this explanation.
