Webb’s 255-hour-long observation reveals invisible dark matter in a map area containing nearly 800,000 galaxies – NotebookCheck.net News
ⓘ NASA
Using its Near-Infrared Camera (NIRCam), NASA’s James Webb Space Telescope peered into a region for a total of about 255 hours. This exceptionally long observation allowed astronomers to trace dark matter by studying how its gravity distorts and influences the light from distant galaxies.
As part of the Cosmic Evolution Survey (COSMOS) project, Webb captured an area of the sky located in the constellation Sextans. The region measures 0.54 square degrees — that is, about two and a half times the size of a Full Moon. This expanse of sky shown in the image contains nearly 800,000 galaxies. The area is also overlaid with a map of dark matter.
Dark matter is not visible to the naked eye or to traditional telescopes. This is because it neither emits, reflects, absorbs, nor blocks light. However, dark matter can be detected because it interacts with the universe through gravity. Large clusters of dark matter can cause a curvature in space-time. As light travels from nearby galaxies to Earth through this curvature, it bends. That bending of light is called gravitational lensing.
Gravitational lensing is of two types: strong and weak. In strong gravitational lensing, the bending of light is significant enough to be visually obvious in images. For weak gravitational lensing, there is a much more subtle distortion of the light. Astronomers analyze thousands of galaxies to identify patterns. This Webb dark matter map is based on weak gravitational lensing.
In this image, the dark matter is represented in blue. Brighter blue areas indicate a higher density of dark matter. While Hubble previously mapped the dark matter in this area of the sky in 2007, Webb’s map reveals new clumps of dark matter, as it contains about twice as many galaxies as Hubble’s map. Webb’s map also offers a higher resolution view.
Several other telescopes have been part of the COSMOS project. Scientists are using the different views to understand how galaxies grow and how dark matter influences their evolution.
Chibuike Okpara – Tech Writer – 369 articles published on Notebookcheck since 2024
I have always been fascinated by technology and digital devices my entire life and even got addicted to it. I have always marveled at the intricacy of even the simplest digital devices and systems around us. I have been writing and publishing articles online for about 6 years now, just about a year ago, I found myself lost in the marvel of smartphones and laptops we have in our hands every day. I developed a passion for learning about new devices and technologies that come with them and at some point, I asked myself, “Why not get into writing tech articles?” It is useless to say I followed up the idea — it is evident. I am an open-minded individual who derives an infinite amount of joy from researching and discovering new information, I believe there is so much to learn and such a short life to live, so I put my time to good use — learning new things. I am a ‘bookworm’ of the internet and digital devices. When I am not writing, you will find me on my devices still, I do explore and admire the beauty of nature and creatures. I am a fast learner and quickly adapt to changes, always looking forward to new adventures.
Chibuike Okpara, 2026-02- 1 (Update: 2026-02- 1)
