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| James Webb Telescope Proves Dark Matter Is Real, Thanks to the Bullet Cluster. |
James Webb Telescope Confirms the Existence of Dark Matter Through Bullet Cluster Galaxy Observations
For decades, scientists have believed that something invisible—something we can’t see, touch, or detect directly—is holding the universe together. That “something” is called dark matter, and now, thanks to data from the James Webb Space Telescope, we have stronger proof than ever that it truly exists.
What Is Dark Matter, and Why Does It Matter?
Let’s break it down: everything we can see in the universe—stars, planets, galaxies, and even humans—only makes up about 5% of the total mass and energy of the universe. The rest is a mix of dark energy and dark matter, which can’t be seen directly but clearly affect how the universe works.
Dark matter doesn’t emit light, absorb it, or reflect it. But it has gravity, and that’s how scientists detect it—by watching how it pulls on things we can see.
The Bullet Cluster: A Cosmic Crash That Reveals the Invisible
A famous example of dark matter in action is the Bullet Cluster, which is actually a collision between two massive galaxy clusters located about 3.8 billion light-years away from Earth.
When scientists observed the collision through X-ray images, they noticed something strange. The hot gas—visible matter—was slowed down during the collision. But the total mass of the system, measured using a technique called gravitational lensing, didn’t stay behind with the gas. Instead, it moved ahead—almost as if something invisible, like a “ghost,” passed right through.
That “ghost” is dark matter. It barely interacts with ordinary matter, so it kept moving while the visible gas got stuck.
How James Webb Helped Confirm the Discovery
To understand this better, researchers from Yonsei University in South Korea and the California Institute of Technology teamed up. They used James Webb’s powerful infrared camera to study the Bullet Cluster in more detail. They also combined this data with information from NASA’s Chandra X-ray Observatory.
What they found was incredible: by studying thousands of galaxies and stars—even those flung out of their systems during the collision—they could map the cluster’s mass more precisely than ever before. And here’s the kicker: the light from these stars followed the same path as the dark matter. That means the stars are helping scientists "see" the invisible.
“We confirmed that intracluster light can be a reliable indicator of dark matter, even in such a dynamic environment,” said Sanjun Cha, a PhD student at Yonsei University.
A More Complex History Than We Thought
The Bullet Cluster didn’t just experience a one-time crash. New findings suggest that the cluster went through multiple smaller collisions both before and after the main event. So, its history is more complicated than scientists originally believed.
Why This Matters to Everyone
Dark matter isn’t just an abstract scientific idea. It makes up about 27% of the universe, and understanding it helps us unlock the deepest secrets of how the universe works—from how galaxies form to what the future of space might look like.
Thanks to advanced tools like the James Webb Telescope, we’re now closer than ever to understanding this invisible but powerful force.