What is Gravitational Lensing and its Cosmological Applications

Einstein Ring due to gravitational lensing
Ring shaped image due to gravitational lensing. Source: NASA

The size of the observable universe is unimaginably large. The galaxies are separated from each other by such a large distance that even light takes millions and billions of year to travel from one galaxy to other. The galaxies present at these distant positions appear as point size and their brightness is so dim that they are invisible to naked eyes. We need various astronomical instruments to observe these distant galaxies. Continue reading “What is Gravitational Lensing and its Cosmological Applications”