What are cosmological surveys?

Cosmological surveys are like taking big pictures of the universe to learn how it works.

Imagine you're playing with a toy train set. You can see all the tracks and trains right in front of you, but if you want to know where they came from or how they're connected, you need to look at more than just your table, you need to look at the whole room, maybe even the whole house. Cosmological surveys are like that, scientists use special tools to take pictures or maps of big parts of space, so they can understand things like where stars and galaxies came from, how fast the universe is growing, and what's out there that we can't see.

Think of it like being a detective. You find clues, maybe footprints in the mud or a broken window, and from those clues, you figure out who did it. Cosmological surveys give scientists clues about the universe, such as how bright stars are or how far away they are. By studying these clues across huge areas of space, scientists can solve mysteries like what’s causing the universe to expand or what made the first stars shine.