QUICK PHYSICS INFO: Gravitational Lens

According to Einstein's theory of relativity, the universe is not flat. The vacuum, which we call it space, has an oblique structure due to the gravitational effect of the material. Every object bends space-time in proportion to its mass. This means that a sufficiently long line in the space will be a curved line that will never be actually linear; just like the light. The light travels at 300,000 km/sec, this is the speed limit of our universe.

Each object in motion has kinetic energy. Photons also have a very small mass that can be measured (energy --> matter --> mass), which is caused by the kinetic energies of the photons. When the light travels in space, the light acts as a non-mass object and each body bends space-time proportional to its mass.

The gravitational lens effect is the result of refracting light from the backgrounds of very large masses and focusing it like a real lens.In other words, clusters of galaxies bend the light and focus like a lens.So, each Galaxy cluster is actually a lens of hundreds of millions of light years.It acts as a telescope much larger than our technology can do.That's how we can study distant galaxies.