Astronomers reveal new details about dark matter’s influence on Universe

(Press-News.org) Scientists have created the highest resolution map of the dark matter that threads through the Universe – showing its influence on the formation of stars, galaxies and planets.

The research, including astronomers from Durham University, UK, tells us more about how this invisible substance helped pull ordinary matter into galaxies like our Milky Way and planets like Earth.

The findings, using new data from NASA’s James Webb Space Telescope (Webb), are published in the journal Nature Astronomy.

The study was jointly led by Durham University, NASA’s Jet Propulsion Laboratory (JPL), and the École Polytechnique Fédéral de Lausanne (EPFL), Switzerland.

The new map confirms previous research and provides new details about the relationship between dark matter and the normal matter from which we – and everything we can touch or see – are made.

When the Universe began, dark matter and normal matter were probably sparsely distributed.

Scientists think dark matter clumped together first and then pulled in normal matter, creating regions where stars and galaxies began to form.

In this way, dark matter determined the large-scale distribution of galaxies we see in the Universe today.

By prompting galaxy and star formation to begin earlier than they would have otherwise, dark matter also played a role in creating the conditions for planets to eventually form. Without it we might not have the elements in our galaxy that allowed life to appear.

Research co-lead author Dr Gavin Leroy, in the Institute for Computational Cosmology, Department of Physics, Durham University, said: “By revealing dark matter with unprecedented precision, our map shows how an invisible component of the Universe has structured visible matter to the point of enabling the emergence of galaxies, stars, and ultimately life itself.

"This map reveals the invisible but essential role of dark matter, the true architect of the Universe, which gradually organises the structures we observe through our telescopes.”

Dark matter does not emit, reflect, absorb, or block light, and it passes through regular matter like a ghost.

However, it does interact with the rest of the Universe through gravity, something the new map shows with a new level of clarity.

Evidence for this interaction lies in the degree of overlap between maps of dark matter and normal matter.

According to the research, Webb’s observations confirm that this close alignment cannot be a coincidence. Instead, the astronomers say it is due to dark matter’s gravity pulling normal matter toward it throughout cosmic history.

Research co-author Professor Richard Massey, in the Institute for Computational Cosmology, Department of Physics, Durham University, said: “Wherever you find normal matter in the Universe today, you also find dark matter.

“Billions of dark matter particles pass through your body every second. There’s no harm, they don’t notice us and just keep going.

“But the whole swirling cloud of dark matter around the Milky Way has enough gravity to hold our entire galaxy together. Without dark matter, the Milky Way would spin itself apart.”

The area covered by the new map is a section of sky about 2.5 times larger than the full Moon, in the constellation Sextans.

Webb peered at this region for a total of about 255 hours and identified nearly 800,000 galaxies, with many detected for the first time.

The scientific team then looked for dark matter by observing how its mass curves space itself, which in turn bends the light traveling to Earth from distant galaxies – as if the light of those galaxies has passed through a warped windowpane.

The map contains about 10 times more galaxies than maps of the area made by ground-based observatories and twice as many as the Hubble Space Telescope.

It reveals new clumps of dark matter and captures a higher-resolution view of the areas previously seen by Hubble.

Research co-lead author Dr Diana Scognamiglio, of NASA’s Jet Propulsion Laboratory, said: “This is the largest dark matter map we’ve made with Webb, and it’s twice as sharp as any dark matter map made by other observatories.

“Previously, we were looking at a blurry picture of dark matter. Now we’re seeing the invisible scaffolding of the Universe in stunning detail, thanks to Webb’s incredible resolution.”

To refine measurements of the distance to many galaxies for the map, the team used Webb’s Mid-Infrared Instrument (MIRI).

Durham University’s Centre for Extragalactic Astronomy was involved in the development of MIRI, which was designed and managed through launch by JPL.

The wavelengths detected by MIRI make it adept at detecting galaxies obscured by cosmic dust clouds.

The team next plans to map dark matter throughout the entire Universe, using the European Space Agency’s (ESA) Euclid telescope and NASA’s upcoming Nancy Grace Roman Space Telescope.

They will learn more about dark matter’s fundamental properties and how dark matter might have changed over cosmic history.

However, that patch of sky studied in this latest research will be the reference on which all future mapping will be fine-tuned and compared. 

The latest research was funded by NASA, the RCUK/Science and Technology Facilities Council (STFC), the Swiss State Secretariat for Education, Research and Innovation (SERI), RCUK/STFC Central Laser Facility at the STFC Rutherford Appleton Laboratory and the Centre National d'Etudes Spatiales.

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