Bullet Cluster

colliding galaxy clusters · dark matter made visible

3.9 billion light-years away

Two clusters collided at 4,500 km/s. Their galaxies and invisible dark matter (blue, mapped by gravitational lensing) sailed through; their hot gas (pink, seen in X-rays) crashed and lagged behind.

• the strongest direct evidence that dark matter is real
• its gas is 100 million °C

kind

place in the universe at large · explosion or collision