Dark Energy in Astronomy and Astrophysics 101


The unidentified energy source that is speeding up the expansion of our universe is known as dark energy.

The universe is getting bigger. The apparent acceleration of the expansion rate is one of the major puzzles of contemporary astronomy. Astrophysicists regard to dark energy as the as-yet unidentified energy source driving this expansion.

The well-known equation E = mc2 illustrates the close relationship between energy and mass. As a result, rather of using merely mass, astronomers frequently characterize the makeup of the Universe in terms of a number known as the mass-energy density. Amazingly, over 70% of the mass-energy density of the entire universe is thought to be made up of dark energy.

Astronomers seek to learn more about dark energy via research, both in terms of what it is and how it can impact the future of the Universe, including whether it will attain a stable state, reverse direction, or experience a "Big Crunch."

Astronomers were able to gauge the speed of the universe's expansion thanks to Hubble's early observations. To their amazement, the data revealed that the expansion of the Universe has been speeding rather than maintaining a steady rate. The presence of dark energy, according to many physicists, can account for this finding.

Hubble enabled scientists to more precisely estimate the separations between stars in 19 galaxies in 2016 than was previously possible. They discovered that the rate of expansion of the universe now is greater than that estimated from observations made just after the Big Bang. This seeming contradiction may hold a key to comprehending three of the Universe's most enigmatic elements: dark matter, dark energy, and neutrinos. Research is currently underway. 

The group accomplished this finding by measuring the Hubble constant, or the rate at which the universe is expanding, with remarkable accuracy and lowering the uncertainty to just 2.4%. This is crucial since estimates of the Hubble constant differed by a factor of two before Hubble's debut in 1990.One of the main objectives of the telescope was attained in the late 1990s when researchers improved the Hubble constant's value to within 10%. The Hubble constant's value is now only unclear by an astonishing 1.9 percent thanks to the most recent study.

An international team of researchers used the COSMOS survey, the largest survey ever conducted with Hubble, to analyze the data and put together one of the most significant discoveries in cosmology: a three-dimensional map that provides a first glimpse at the web-like large-scale distribution of dark matter in the Universe. This method of tracking the development of clustering in dark matter may ultimately provide insight into dark energy.

It was revealed in 2010 that an international team of astronomers had made a significant advancement in their attempt to unravel the mystery of dark energy by using gravitational lensing measurements from Hubble. Astronomers can retrace the route that light from far-off galaxies takes on its protracted journey to Earth by examining the distorted pictures. Additionally, it enables them to research how dark energy affects the geometry of space along the light path from far-off objects to the lensing cluster and from the cluster to our galaxy. 

The precise route that the light beams take as they travel through space and are bent by the lens is gradually changed as dark energy forces the Universe to expand even more quickly.This implies that the distorted pictures produced by the lens include data about both the lens and the underlying universe.