The spacetime continuum is a fabric, which contains space and time. It is a mathematical model that combines our 3-dimensional space, with time, to form a single interwoven fabric. The space between two yarns in the fabric is the smallest physics can go. Going smaller that that defies physics. The smallest hypothetical particle, the Planck’s Particle, which is 10-20 the size of a proton, will nearly fit on one square of the fabric, between four yarns.
Anything with mass bends this fabric. Our sun will have a bigger impact on the fabric, compared to the earth, which means the fabric bends relative to the mass of the object.
In the image, the yellow particle has more mass, so it has more impact on the shape of the fabric, but the red particle has a lower mass, so it has a lower impact on the fabric.
This concept has helped physicists simplify complex theories, from the subatomic to the supergalactic.