Galaxies on Course for a Second Massive Collision

Imagine two giant groups of galaxies, like massive cities, that crashed into each other a long time ago.

Now, they're slowly moving back together for another crash!

Scientists are using telescopes like the Chandra X-ray Observatory to watch this happen.

These groups, called galaxy clusters, are made of thousands of galaxies, super hot gas, and invisible stuff called dark matter, all held together by gravity.

When they first crashed, it made shockwaves, like huge sonic booms.

Now, these shockwaves are super far apart, and the groups are getting closer again.

This special event is giving scientists a unique chance to learn about how these giant structures in space crash and grow.