Scalar field dark matter is a type of invisible matter that is believed to exist in our universe.
Imagine that our universe is like a giant ocean, where everything that we can see - stars, planets, and galaxies - are like boats sailing on the surface. Scalar field dark matter is like a current that flows beneath the surface, pushing and pulling the boats of visible matter.
But scalar field dark matter is not made up of particles like regular matter. Instead, it is made up of a type of field that permeates all of space. Think of it like a giant invisible blanket that covers our entire universe.
This field can have a certain amount of energy stored in it. This energy can manifest itself as particles that behave like they have mass - which is why scalar field dark matter is often referred to as "massive" or "cold" dark matter.
Scientists have not directly observed scalar field dark matter yet. Instead, they infer its existence from the way that it affects visible matter through gravity. It has been proposed as a potential solution to explain the distribution of dark matter in galaxies and the large scale structure of the universe.
So, in summary, scalar field dark matter is a type of invisible matter that exists throughout the universe and affects visible matter through gravity. It is made up of a type of field that can have stored energy, which manifests as particles that behave like they have mass.