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”

What is Dark Matter? In Simple Terms Here

what is Dark matter in galaxy
Dark matter around a galaxy ( Illustration: NASA/CXC/M.Weiss)

Human are always curious to understand the nature and its phenomenon. When we look towards the space, we find that the space contains large number of massive objects like asteroids, planets, stars, clusters, galaxies. The size of any galaxy is enormously large that we can’t imagine. Even our sun is very large although it is an average star. But you will be surprised to know that all these objects like stars and galaxies taken together make just 5 % of total content of the universe. Are you curious to know where the remaining part of the Continue reading “What is Dark Matter? In Simple Terms Here”

What will happen during Collision of Milky Way with Andromeda Galaxy?

Andromeda Galaxy
Andromeda Galaxy is 50% bigger than our Milky Way. (Credit: NASA)

You must have heard about the collision of an asteroid with the planet and aware of the destruction that can be caused by such an event. But there is one bigger cosmic event that is the collision of our Milky Way Galaxy with the Andromeda Galaxy. These two galaxies will merge to form a new galaxy in future. This was the common process of formation of new galaxies after the big bang. Continue reading “What will happen during Collision of Milky Way with Andromeda Galaxy?”

How do astronomers measure the speed of the Galaxy?

The Andromeda Galaxy
The Andromeda Galaxy is moving towards us with relative speed 225 Km/s (Credit: NASA/JPL-Caltech)

The galaxies are present at such a large distance from the Earth that the motion of galaxies cannot be observed through a telescope. No observable change in the position will be detected even if we observe any galaxy throughout life. Then, you must be wondering how the speed of the galaxy is measured by astronomers? Continue reading “How do astronomers measure the speed of the Galaxy?”