A groundbreaking new observatory that will build the most accurate map of the universe ever could solve two of science’s most pressing mysteries: the nature of dark energy and dark matter. Together, these components form what is known as the dark universe.
the Vera C. Rubin Observatory Currently under development atop El Peñón on Chile’s Cerro Pachón mountain, it is scheduled to begin operations in 2025. When that happens, Rubin will conduct a Legacy Survey of Space and Time (LSST), observing the entire southern visible sky every few days. s more than 10 years. It will capture up to 1,000 images of the sky on each of those nights, giving scientists an exciting new view of the sky. Universe And insights into how it will develop.
As he does so, Robin’s wide field of vision will reveal how a network of… Dark matter It distorts images of distant galaxies, which will allow scientists to better map the mysterious matter. Because this vast cosmic web seems to pull galaxies together Dark energy Driving them apart, this could reveal details of the cosmic “tug of war” and, in turn, how dark energy and dark matter intertwine to form the universe.
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“With Rubin, we will have it all,” Andrés Alejandro Plazas Malagon, Rubin’s operations scientist, said. He said in a statement. “We will measure the properties of a much larger number of galaxies than we have now, which will give us the statistical power to use weak lensing to map the distribution of dark matter and study how dark energy evolves over time.”
How can Robin shine light into the dark universe
Dark matter and dark energy present a challenge for researchers to study, because although they account for 95% of the total energy and matter content of the universe (dark matter accounts for 27% and dark energy accounts for 68%), they are essentially invisible to us. It means things that make up starsThe planets and everything around us on a daily basis (including our bodies) represents only 5% of the content of the universe.
The reason dark matter cannot be seen is that it does not interact with light. It can therefore only be inferred from the effects of gravity on light and “ordinary” matter that we can actually see. In fact, these gravitational effects literally help hold the contents of galaxies together as they rotate, a discovery made by an American astronomer. Vera C. Rubin, which gave its name to this new revolutionary observatory. While dark matter binds galaxies together internally, those same galaxies are also clustering together meaning matter is spread over a much larger scale, keeping the structure of the universe strong.
Dark energy also acts on a larger scale, accelerating the expansion of the universe, pushing galaxies away from each other faster (and faster) as they interact with the very fabric of the universe. place and time.
“You can think of dark matter as trying to build up cosmic structures, while dark energy is actually trying to loosen them up and push them away,” Plaza-Malagon said.
The action of dark energy is described by a cosmological constant, but this has been described as “the worst theoretical prediction in the history of physics” by some scientists, which is not really an exaggeration either. The constant, as predicted by quantum field theory and accounting for all the particles in the universe, is larger than the value measured by astronomers making observations of the universe — by 120 orders of magnitude.
This is equivalent to measuring a bag of sugar and finding that it weighs 1 pound, while expecting the number of individual sugar grains you created to weigh 10^120 pounds (1 followed by 120 zeros).
Rubin could help determine an accurate value for the cosmological constant by better mapping the universe’s extended invisible cosmic web of dark matter using a phenomenon called gravitational lensing, which was first predicted by Albert Einstein In his 1915 theory of General relativity,
General relativity suggests that objects with mass have a “distorting” effect on the fabric of the universe. The greater the mass, the more extreme the counterfeit. This distortion of space-time is understandable gravity Arises.
When light passes through one of these warps or “scratches” in spacetime, its path becomes curved. This means that when an object with a large mass falls between them Land As a distant light source, light from this background source can take paths around the interfering object that are curved to different ends depending on how close they are to the interfering object itself. Sometimes, these paths cause the light source to appear magnified from our vantage point on Earth. The phenomenon is known as “Gravitational lens“.
Dark matter also has mass; Thus, it participates in this bending of light even though the mysterious form of matter does not interact with light. This effect has been used to determine that most galaxies are surrounded by a halo of dark matter.
In extreme cases called “strong lensing,” the effect of curved space-time can cause objects to appear multiple times in the same image or cause a background object to appear smeared or distorted. This can amplify this light, allowing distant and faint objects to be seen. However, there are more subtle cases of Gravitational lens It’s called the “weak lens” and is useful in itself.
“If a strong lens is like looking through the bottom of a wine glass, a weak lens is like looking through a large, very subtly distorted window,” Theo Schott, Ph.D., at Stanford University. The candidate said in the statement.
Weak lensing can occur not only at the edges of strong lensing effects generated by a massive object (such as a galaxy or star cluster) but also as a result of the large-scale cosmic web of dark matter that is thought to permeate the universe. This results in subtle distortions in distant galaxies that are usually too slight to be seen on their own, but are calculable when the cumulative warping effect on many galaxies at once is taken into account.
This ultimately means weak lensing due to the dark matter web in the universe, which requires a large data set of galaxies and a view of the collective distortion across the sky.
And this is where Robin will come in.
Through a huge field of view provided by the 8.4-meter telescope equipped with the largest digital camera in the world, the observatory will be able to visualize huge patches of sky and collect data about billions of galaxies and their shapes. In fact, Rubin could be so powerful that he has the potential to suggest evidence that dark matter and dark energy are not the proper components of the universe at all — and that a modified theory of gravity may be needed to explain the universe we live in. We see around us.
“Dark energy is a concept that fits into the theory of gravity accepted within Einstein’s general theory of relativity, but Rubin and LSST will also allow us to explore alternatives to that, which is incredibly exciting as well,” concluded Plaza-Malagon.
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