Hubble’s Inside the Image: Lensed Supernova Refsdal - YouTube - NASA Goddard - astrophysics

Albert Einstein predicted gravitational lensing,the warping of spacetime by the gravitational pull of massive objects such as galaxies.Gravity is actually a curvature in spacetime and can have the effect of enabling observation of very distant objects.This can also be used to ascertain how fast the universe is expanding.

Hubble’s Inside The Image: Abell 2744 - NASA Goddard - astrophysics

Because of the intense gravity exerted by galaxy cluster Abell 2744,gravitational lensing,which is a curvature of space,occurs as predicted by Albert Einstein and we are able to look back in time at galaxies in the early universe about 12 billion light years away.The universe is about 13.8 billion years old.Galaxy cluster Abell 2744 also contains dark matter.