Webb Data Reveals Dark Matter

Unveiling the Invisible: How Webb Data Reveals Dark Matter

The universe is full of mysteries waiting to be unraveled, and one of the most enduring enigmas is dark matter. This invisible substance makes up approximately 27% of the universe's mass-energy density, yet it remains invisible to our telescopes. However, thanks to the James Webb Space Telescope (JWST), scientists have made a groundbreaking discovery that sheds new light on dark matter's distribution in the universe.

A Map of Dark Matter

The image from NASA's JWST, PIA26702, is a stunning representation of nearly 800,000 galaxies overlaid with a map of dark matter. The map is represented in blue, with brighter areas indicating a higher density of dark matter. This area of sky, located in the constellation Sextans, is 0.54 square degrees (about 2½ times the size of the full Moon) and was observed by JWST's Near-Infrared Camera (NIRCam) for a total of about 255 hours.

The Invisible Substance

Dark matter doesn't emit, reflect, absorb, or even block light, making it invisible to the human eye or traditional telescopes. However, it does interact with the universe through gravity, and large clumps or clusters of dark matter have enough mass to curve space itself. Light traveling to Earth from distant galaxies becomes slightly distorted as it passes through the curved fabric of spacetime. In some cases, the warping is significant enough that it is apparent to the naked eye, almost as if the galaxy were being viewed through a warped windowpane, an effect called strong gravitational lensing.

Weak Gravitational Lensing

In the case of the dark matter map shown here, scientists inferred dark matter's distribution by relying instead on an effect called weak gravitational lensing, which leads to much more subtle distortions of the light from thousands of galaxies. This method allows researchers to map the distribution of dark matter on a much larger scale than previously possible.

A Higher-Resolution View

The dark matter map revealed by JWST contains about 10 times more galaxies than do maps of the area made by ground-based observatories and twice as many as Hubble's map. It reveals new clumps of dark matter and captures a higher-resolution view compared to the Hubble map. This breakthrough is a testament to the power of JWST and its ability to observe the universe in unprecedented detail.

The Cosmic Evolution Survey (COSMOS)

The full COSMOS "field" is 2 square degrees (about 10 times the size of the full Moon) and has been imaged by at least 15 telescopes in space and on the ground. Observing the same region with many different telescopes allows scientists to combine complementary views to understand how galaxies grow and how dark matter influences their evolution. Only JWST and Hubble data have been used to map dark matter in the region.

Refining Measurements

To refine measurements of the distance to many galaxies for the map, the team used JWST's Mid-Infrared Instrument (MIRI), designed and managed through launch by the agency's Jet Propulsion Laboratory, along with other space- and ground-based telescopes. The wavelengths that MIRI detects also make it adept at detecting galaxies obscured by cosmic dust clouds.

Implications and Future Directions

The discovery of dark matter's distribution in the universe has significant implications for our understanding of the cosmos. It provides new insights into the evolution of galaxies and the role of dark matter in shaping their structure. This breakthrough also opens up new avenues for research, including the study of dark matter's properties and its potential impact on the universe's large-scale structure.

Conclusion

The James Webb Space Telescope has once again pushed the boundaries of our understanding of the universe, revealing the invisible distribution of dark matter in unprecedented detail. This discovery is a testament to the power of human ingenuity and the importance of continued investment in space exploration. As we continue to explore the universe, we may uncover even more secrets and mysteries waiting to be unraveled.

Source: https://science.nasa.gov/photojournal/webb-data-reveals-dark-matter/