With a massive and expensive astronomical kit, an astronomer will look forward to every hour waiting to see 'first light' . For years preparing equipment and algorithms to calculate the path of light, they waited patiently for the first particles of light from a distant object to reach the telescope.
The first light is not that simple: it sometimes carries new data, allowing new aspects of science to exist.
On October 22, the Dark Energy Spectrometer (DESI) at the Mayall Observatory in Arizona, USA achieved the 'first light' achievement. This is a new turning point in astronomy: the ability to measure the distances between galaxies has improved, opening a new era in 'mapping' the structure of the universe.
This head light has yet another meaning: it could be the key to explaining 'dark energy' , the force thought to cause the expansion of the Universe. Based on the model of modern cosmology, dark energy will account for 68% of the total energy in the universe.
The universe is a chaotic set. Galaxies 'live' together in groups from a few to a few dozen galaxies. Besides, there are clusters of galaxies containing hundreds to thousands of galaxies, and then even super clusters including many 'small' clusters . From the first Universe maps, drawn by the Redshift Survey of the Center for Astrophysics, we see how complicated and confusing the Universe is.
Those are the first images that show the scale of giant structures in the Universe, with galaxies hundreds of millions of light years wide.
The first maps of the universe.
The Center for Astrophysics (CfA) survey can only model one galaxy at a time. The work is too much for them to 'hug' many galaxies at a time; they will have to measure the spectrum of the light emitted from the galaxy, identifying traces of chemical elements (primarily hydrogen, nitro and oxygen).
These chemical traces will produce wavelengths bearing red, created by the impact of expansion of the Universe.
Astronomer Vesto Slipher was the first to discover the 'red shift' steps , so that later people could figure out Hubble's law - the first principle to observe and explain the expansion of the The universe, often used to support the Big Bang model, Hubble's law shows that distant galaxies are creating distance from the Milky Way at an increasingly high speed.
This suggests that nearby galaxies travel farther away from the Milky Way than distant galaxies, because they appear to have less 'redshifts' . From this, we infer a way to measure the distances between galaxies, which is to measure redshifts.
Map of SDSS, with every dot as a galaxy.
More importantly, the relationship between the red transition and the distance of galaxies is based on the expanding history of the Universe, which can be calculated through the existing theories of gravity, about interrelated assumptions. concerning the density of matter and the energy in the Universe.
All of these assumptions have been brought to the table by a new Cosmic Observatory test, accompanied by another 3D map obtained after a major red-shift survey. More specifically, the Sloan Digital Sky Survey (SDSS) is the first to use specialized telescopes to measure the redshifts of millions of galaxies, drawing a large scale map of the Universe. never happend.
The SDSS map includes hundreds of megalithic clusters, galaxy filaments - the largest structure that exists in space at the size of 200-500 million light years, and it has helped science to have Unexpectedly discovered: it is dark energy.
The map shows that the density of matter in the Universe is lower than estimated after observing the Cosmic Microwave Background - the light left over from the Big Bang.
From this, the scientists deduced that there was a missing unknown in the equation of the Universe, they called it the dark energy, which is causing the Universe to expand in all directions and causing more space to contain matter. appear.
The puzzle is complicated by the day, probably proportional to the expansion of the universe
Combining all these observations, the scientists opened up a new chapter of books, understanding that the Universe contains 30% matter and 70% dark matter. But even though most physicists recognize the existence of dark matter, we still don't know where it came from.
Again, science has to make conjectures, guessing the wrong way, then guessing until it can be proved. Many researchers believe that the energy that exists in this vacuum has a certain value, they call it the 'cosmological constant'. Many others believe that Einstein's theory of relativity is not yet complete enough to apply to the enormous scale of the Universe.
New devices like DESI will be able to add missing pieces. It will measure the redshifts of tens of millions of different galaxies, galaxies within a radius of 10 billion light-years around the Earth.
Such an amazingly detailed map will answer some of the questions about dark energy that still scare science, besides solving a mystery about the structure of the Universe. For example, we will know if dark energy is a cosmological constant.
The team of scientists stands in front of DESI's lens.
To do that, they will measure the percentage of pressure that dark energy presses on the Universe with the amount of energy measured in each cubic unit. If the dark energy is a constant, this ratio will also be constant at all times and places. If we have a constant - a solid anchor to hold on to, a series of new theories will form.
DESI will even change or even refute even theories that we have regarding gravity. This will be the evolution of theoretical physics. And yet, DESI is just one of many missions, dark energy research experiments will appear in the next decade, a series of studies that will keep us excited and a future that is not covered by 'dark' energy. .
Based on an article by cosmological professor Bob Nichol, published in The Conversation.